# New Piston and rings for two stroke.



## Pathfinder13 (Feb 28, 2014)

Has anyone "re-ringed" a two stroke Briggs R-Tek engine here ? It's from a Toro CCR3650. I can't seem to dig up any info on this except that the cylinder walls should be honed with a ball-hone of the proper size only to refresh the surface for the new rings to wear into (obviously remove slight scoring that happened with a cross hatch) and this should be done very carefully with motor oil as the lube. 

Should I use two stroke oil as the lube for the ball-hone, or regular stuff ? 

I'm thinking 2-stroke but not sure on this one. All I know about it is that it has lower ash content that's about it. I know the ports need to be carefully passed of as to creat as little damage as possible. 

My piston had some scoring, the cylinder walls were cast iron thet looked better but not perfect. I bought a fresh original Briggs piston, it came with new rings, and wrist-pin, and clips for the wrist-pin. I am aware of the orientation of the rings as there were instructions in the box. Also read online about coating everything as it's installed, rings, pins, piston, ect. with two-stroke oil during assembly.

I have not begun yet, it's cold in the garage, but Saturday I'm going to blow some heat in there and get started.

I would like and appreciate ANY and all insight that anyone in-the-know can offer , tips, ect as I have never done this before  and I am not pretending to know how, I only mentioned what I have read and seen on YouTube on the two stroke vids (some were yamaha 2-stroke MC rebuild vids) and one web site that offered a little, but it was vague.


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## fixer5000 (Nov 3, 2013)

ive done a few two stroke snowmobile engines with the ball hone. lotsa oil of any kind pretty much and dont go too crazy with it. wash it out really good after your done and reassemble it all with oil coated parts


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## Pathfinder13 (Feb 28, 2014)

fixer5000 said:


> ive done a few two stroke snowmobile engines with the ball hone. lotsa oil of any kind pretty much and dont go too crazy with it. wash it out really good after your done and reassemble it all with oil coated parts


Thanks I will do that. I have not got the ball-hone yet, have to order it tonight. The piston itself between the top and the rings slots measures 2.485" so I need to research which exact ball hone to purchase. Any insight would be helpful


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## Shryp (Jan 1, 2011)

I don't know if they have hones, but check the local auto parts stores for the tool loaner programs. Pay a deposit to get the tool and then take it back within 90 days for a refund.


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## Prof100 (Feb 9, 2015)

Pathfinder13 said:


> Thanks I will do that. I have not got the ball-hone yet, have to order it tonight. The piston itself between the top and the rings slots measures 2.485" so I need to research which exact ball hone to purchase. Any insight would be helpful


 If the bore is not chewed up the berry hone works well.









Here is a link to Engine Repair site that discusses the honing process.
Engine Cylinder Hone


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## Pathfinder13 (Feb 28, 2014)

Shryp said:


> I don't know if they have hones, but check the local auto parts stores for the tool loaner programs. Pay a deposit to get the tool and then take it back within 90 days for a refund.


I looked into this last week, they don't as the tools wear with use. Advance Auto told me this. Ebay has them for cheap enough, just have to decide the exact size / grit to purchase.


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## Prof100 (Feb 9, 2015)

Pathfinder13 said:


> I looked into this last week, they don't as the tools wear with use. Advance Auto told me this. Ebay has them for cheap enough, just have to decide the exact size / grit to purchase.


Here you go... video and oil recommendation.
Technical information on using engine hones, flex-hones, ball hones


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## Pathfinder13 (Feb 28, 2014)

Prof100 said:


> Here you go... video and oil recommendation.
> Technical information on using engine hones, flex-hones, ball hones


Thank you, I will watch this late tonight after work, and look at the details. Much appreciated !


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## Grunt (Nov 11, 2013)

Here is a LINK to the Briggs two stroke service manual, if you don't already have it. Good luck with the rebuild.
Another LINK just in case.


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## classiccat (Mar 1, 2014)

Good luck Path!


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## Pathfinder13 (Feb 28, 2014)

Grunt said:


> Here is a LINK to the Briggs two stroke service manual, if you don't already have it. Good luck with the rebuild.
> Another LINK just in case.


That's great Grunt , Thank you. I am going to download might even print depending on how long thank you. I do have a PC in the garage anyhow so can refer directly to it. Hopefully the cylinder wall will clean up I am unsure of if it's perfectly round that;s my main worry. Seems to be -measured with my dial caliper but I lack the special T type mic that real engine guys use. thanks again !


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## Pathfinder13 (Feb 28, 2014)

Well.. I downloaded the Briggs Service Manual (thanks again brother Grunt !) and ordered the head gasket, 515 sealant for the lower end, and a flex-hone so there's no turning back now ;-)

Anyone that has rebuilt an Rtek (or a duraforce for that matter) before and has any story or tips on the Rtek, I'll be keeping my eyes on the post. Thanks.


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## Prof100 (Feb 9, 2015)

Pathfinder13 said:


> Well.. I downloaded the Briggs Service Manual (thanks again brother Grunt !) and ordered the head gasket, 515 sealant for the lower end, and a flex-hone so there's no turning back now ;-)
> 
> Anyone that has rebuilt an Rtek (or a duraforce for that matter) before and has any story or tips on the Rtek, I'll be keeping my eyes on the post. Thanks.


Take pictures of the rebuild and post to Facebook then paste the image in your post. The attachments on this forum are clumsy.


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## Pathfinder13 (Feb 28, 2014)

Prof100 said:


> Take pictures of the rebuild and post to Facebook then paste the image in your post. The attachments on this forum are clumsy.


I'm not having any issues with the pics on the forum. As a note, I am using Chrome as a browser... if you are using IE  or Safari  that may be your issue, I also use Firefox but find Chrome working best here. Also, I'm not on FB.. tried it and really disliked all the %$^& I saw going on so I abandoned it long ago. You may want to try a different browser. 

I might do a thread.. good idea Pro.. all I had thought about was research and figure out the plan of action at this point but if I get it running I'll post some.


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## Grunt (Nov 11, 2013)

I can't help with rebuilding info on that size motor, but I have redone a few weed eater motors. Insuring a good seal between the crank case halves is essential as is having "GOOD SEALS" on both sides of the crank shaft. Two strokes develop both compression and vacuum in the crank case and being air tight is mandatory to a good running two cycle.


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## sj701 (Jan 23, 2014)

Those can be rebuilt if the damage to the cylinder isn't too extensive, if you have grooves from the needles or other debris in the bore, it's trash. I've done about 3 of the Rteks and alot of Tecumseh 2 strokes over the years. 

Believe it or not the pile of parts in the one photo is running again with a used Lawnboy rod, new Briggs piston/rings, and a fresh hone to the cylinder. It is the assembled engine on the right in the other photo next to the newer Briggs built version on the left.

It didn't have really bad scoring and the rod broke in a way so it didn't punch a hole in the casting so it could be saved.

If you have an old Lawnboy Duraforce lying around the piston and rod are the same as is used in the Rtek so you can steal some parts out of it. Also the Lawnboy F rod will work in a pinch, it has the same length and bearing size but smaller cross section. If your rod is still in one piece but was run without oil look at the bearings to see if they have turned blue from heat which is bad.

So if you still think it can be saved, go get a hone, I prefer the 3 stone type myself. Hone the cylinder until all traces of the aluminum that transferred from the piston is gone and break the glaze so the new rings will seat. Oil on hone doesn't really matter, I usually use 30wt engine oil. Then wash the engine really good with grease cutting dish soap and water and a scrub it hard with a nylon brush to remove all the grit from honing. Then oil bore with WD40 immediatly to prevent rust. Blow dry all the water and WD40 off with compressed air, and oil again. Now you are ready to inspect the bore and see if the process needs to be repeated again, you don't want any high spots on the bore or left over transferred piston material on the liner. Washing in a parts washer or using solvent will not remove the hone grit completely.

If all looks good it's time to reassemble using 2 stroke oil on all the bearings, piston rings ect. Then seal up the crankcase halves with ThreeBond 1211 or your favorite sealant, clean the oil off the mating surfaces first with solvent. Let it cure for 24hours minimum before running it.


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## Pathfinder13 (Feb 28, 2014)

sj701 said:


> Those can be rebuilt if the damage to the cylinder isn't too extensive, if you have grooves from the needles or other debris in the bore, it's trash. I've done about 3 of the Rteks and alot of Tecumseh 2 strokes over the years.
> 
> Believe it or not the pile of parts in the one photo is running again with a used Lawnboy rod, new Briggs piston/rings, and a fresh hone to the cylinder. It is the assembled engine on the right in the other photo next to the newer Briggs built version on the left.
> 
> ...


Those tips are appreciated, thank you SJ  

I'm going to get into it tomorrow at some point, I have not looked at the needle bearings yet and am hoping they are not blued. Lots of iffy stuff with this project I can see now, half of me wishes I had not taken this on, the other half of me says it's good experience even if I'm rolling the dice with about 70 bucks in parts and sealant and the flex-home I bought. 

Oh well, it's too late to turn back, now I just need to pay attention to the tips and the details and not rush it. I notice that these engines are not just everywhere you look if I should run amuck I may just need to put it aside until I find a donor. Wow, that could be a while. Hoping I get lucky with this one.


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## sj701 (Jan 23, 2014)

Pathfinder13 said:


> Those tips are appreciated, thank you SJ
> 
> I'm going to get into it tomorrow at some point, I have not looked at the needle bearings yet and am hoping they are not blued. Lots of iffy stuff with this project I can see now, half of me wishes I had not taken this on, the other half of me says it's good experience even if I'm rolling the dice with about 70 bucks in parts and sealant and the flex-home I bought.
> 
> Oh well, it's too late to turn back, now I just need to pay attention to the tips and the details and not rush it. I notice that these engines are not just everywhere you look if I should run amuck I may just need to put it aside until I find a donor. Wow, that could be a while. Hoping I get lucky with this one.


No problem, no better way to learn than to give it a try. Don't over hone it, just enough to break the glaze and remove the ugly stuff. Too much and it won't run strong. 

You are correct, due to EPA regulations once the short block that are available now on the dealer shelves are gone that's it. Used engines can be found but they are snapped up quick, best to find them in a used unit with a frame that has rusted away. And all the complete engines are gone from the distributors at this point. 

The rods in the Rteks are the weak link so most will probably die that way in time. Most aren't rebuildable after that failure. Ones that were run without oil have a better chance of being saved provided the cylinder isn't gouged too deep.


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## bosco659 (Feb 1, 2013)

Duraforce aka Rtek short blocks are on eBay now for as low as $75 plus shipping. Rebuilding a motor can be a fun project but the short block can be a viable option if you haven't bought parts and tools already. I have Duraforce engines in my lawnmowers and one snowblower and I plan to buy at least one short block as a spare before the supply dries up.

If you have aluminum deposits on the cast iron bore, sometimes you have to work the hone too hard to get rid of them and then you end up over boring the rest of the cylinder. I always attempt to remove the aluminum prior to honing. This can be done chemically or VERY carefully with the proper abrasives and tools.


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## sj701 (Jan 23, 2014)

bosco659 said:


> Duraforce aka Rtek short blocks are on eBay now for as low as $75 plus shipping. Rebuilding a motor can be a fun project but the short block can be a viable option if you haven't bought parts and tools already. I have Duraforce engines in my lawnmowers and one snowblower and I plan to buy at least one short block as a spare before the supply dries up.
> 
> If you have aluminum deposits on the cast iron bore, sometimes you have to work the hone too hard to get rid of them and then you end up over boring the rest of the cylinder. I always attempt to remove the aluminum prior to honing. This can be done chemically or VERY carefully with the proper abrasives and tools.


Yes Duraforce shortblocks can be purchased for about $75 on Ebay but the only part that will work in a Rtek is the piston and rod. The crank, and cylinder are different between the two. Rtek short blocks are currently going for about double that cost. Similar engines but not interchangeable.

And you are correct it is best to get as much of the aluminum on the cylinder bore off before honing so you remove less material overall. Acid or dremel tools can accomplish this, like you stated very carefully.


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## bosco659 (Feb 1, 2013)

sj701 said:


> Yes Duraforce shortblocks can be purchased for about $75 on Ebay but the only part that will work in a Rtek is the piston and rod. The crank, and cylinder are different between the two. Rtek short blocks are currently going for about double that cost. Similar engines but not interchangeable.
> 
> And you are correct it is best to get as much of the aluminum on the cylinder bore off before honing so you remove less material overall. Acid or dremel tools can accomplish this, like you stated very carefully.


Thanks for the clarification about the Rtek engine.


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## Pathfinder13 (Feb 28, 2014)

Just a small update. Had a little progress but still on the bench. Weekend got busy unexpectedly. Things look to be coming along well, taking it slow and reading the Briggs overhaul section as I go one step at a time. I could not get the flywheel off, I was afraid I would damage it if I hit it harder (dead blow platic hammer) so I left it intact, luckily the seal looks fine so I cleaned it well and am reusing. So far so good. Going to continue a bit more tomorrow and wed. so I can get the thing together and allow ample gasket seal set time before attempting first start. 

my one question remains .. upon reassembling the two halves ..when applying the gasket maker 515 loctite to the one half of the casing, how big of a bead ? 3/16" , 1/4" ? obviusly I need to apply it right up to the seal I am just worried about applying too much. 

SJ701 ?? Or anyone with this experince ? Your help has been appreciated.


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## Prof100 (Feb 9, 2015)

Pathfinder13 said:


> Just a small update. Had a little progress but still on the bench. Weekend got busy unexpectedly. Things look to be coming along well, taking it slow and reading the Briggs overhaul section as I go one step at a time. I could not get the flywheel off, I was afraid I would damage it if I hit it harder (dead blow platic hammer) so I left it intact, luckily the seal looks fine so I cleaned it well and am reusing. So far so good. Going to continue a bit more tomorrow and wed. so I can get the thing together and allow ample gasket seal set time before attempting first start.
> 
> my one question remains .. upon reassembling the two halves ..when applying the gasket maker 515 loctite to the one half of the casing, how big of a bead ? 3/16" , 1/4" ? obviusly I need to apply it right up to the seal I am just worried about applying too much.
> 
> SJ701 ?? Or anyone with this experince ? Your help has been appreciated.


Pathfinder,

Width of bead controlled within 1/16" is heck of a question. Never in my life have I been able to control the bead to within 1/16". Is there a specification? I would hope not because hand applied gasket maker is more an art form than a science in a home shop. In a mass production facility the application of gasket maker is tightly controlled to save on wasted sealants. Excess amounts end up being wiped off or plugging a passage.

I would suggest to do your best to follow the spec but lose no sleep over it if you use too much. Too little is more of a problem because you don't get a seal.

Bill


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## Pathfinder13 (Feb 28, 2014)

Prof100 said:


> Pathfinder,
> 
> Width of bead controlled within 1/16" is heck of a question. Never in my life have I been able to control the bead to within 1/16". Is there a specification? I would hope not because hand applied gasket maker is more an art form than a science in a home shop. In a mass production facility the application of gasket maker is tightly controlled to save on wasted sealants. Excess amounts end up being wiped off or plugging a passage.
> 
> ...


Thanks Bill. Yeah too little not good for sure. Well, I looked for a spec and found nothing so that's why I'm asking. I just want an idea, and yes I can control a bead (with a short test on scrap) by snipping the end of the tube tight and controlling speed.

I used to assemble sealed equipment for the navy so I kind of have a knack for it. I do need an idea of how much of a bead to put on a crankcase half though as I never did one of these before. 

I'm hoping someone with experince will see ithe question.


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## sj701 (Jan 23, 2014)

I wouldn't put too much sealant on the mating surfaces. Clean off all the old material you can, I usually use laquer thinner and a plastic sharp edge scraper. Then I would apply a thin bead of sealant and smear it around with my finger and then bolt it together and torque it per the manual, I've had good results this way. Once the parts are mated there shouldn't be much clearance so you don't need much to fill the gaps. Too much and you make a mess on the inside and outside with squished out sealant. Outside you can wipe off, inside engine is in there for good, but like Prof100 said it's kinda a judgement call on how much to use. 

You're probably gonna want to try to get that flywheel off so you can get the crank seals good and square when you bolt the engine back together, it may cause headaches during assembly. You may want to try a dry fitup before you have the sealant in place, I've never tried to put one together with the flywheel still on the crank, so it may be a non issue. I forget if you can use a harmonic balancer puller on that one or not, if so it can be rented at Autozone or Advance Auto.


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## Pathfinder13 (Feb 28, 2014)

sj701 said:


> I wouldn't put too much sealant on the mating surfaces. Clean off all the old material you can, I usually use laquer thinner and a plastic sharp edge scraper. Then I would apply a thin bead of sealant and smear it around with my finger and then bolt it together and torque it per the manual, I've had good results this way. Once the parts are mated there shouldn't be much clearance so you don't need much to fill the gaps. Too much and you make a mess on the inside and outside with squished out sealant. Outside you can wipe off, inside engine is in there for good, but like Prof100 said it's kinda a judgement call on how much to use.
> 
> You're probably gonna want to try to get that flywheel off so you can get the crank seals good and square when you bolt the engine back together, it may cause headaches during assembly. You may want to try a dry fitup before you have the sealant in place, I've never tried to put one together with the flywheel still on the crank, so it may be a non issue. I forget if you can use a harmonic balancer puller on that one or not, if so it can be rented at Autozone or Advance Auto.


Thanks SJ, I have done a dry fit and the seals are right where they are supposed to be and they stayed in place when I carefully pulled the top half back off, the crankshaft and flywheel weight was holding them firm. 

I just got the primer today, hard time finding the primer but finally I hit Advance Auto and they had some, pricey stuff 19 bucks for a small can. I was unaware that I needed it when I ordered all the rest, the Briggs manual says nothing about it,  I read it on the back of the sealant package after I got that. I'm using the 515 recomended in the Briggs manual.

If the engine ends up running well, I may look into how to get the bearings off the flywheel as I wanted to replace then but seems they are pressed on so I'd probably have to take it to a shop to remove the old and press on the new ones. Theys seemed OK after flushing them and oiling but if the machine runs good I'd like to figure out how to get them off the crank and get new ones pressed on. I did not want to spend the extra up front, being unsure if I would have good compression after the honing. It will be worth putting a little extra money into it to insure a long life if it runs decent. 

Thank you for the insight, it's nice to have input from one who has rebuilt these Rtek's before ! The forum here is full of great folks. I lend my insight when I have experience on something, but sometimes I need help too.


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## sj701 (Jan 23, 2014)

No problem. I've always enjoyed repairing these Rteks, especially the ones most people would consider too far gone to work on. I haven't used the 515 sealant before so hopefully my methods transfer over, I've always used the Threebond 1211 rtv, I figure if it's good enough to seal cases on my Yamaha waverunner rebuilds, it ought to work on the Rteks, and it has. 

You are correct, everyone has talents, just have to find the one for you...and rely on others for their insight when you need help.

Now if I could just find a replacement trunnion for my Powermatic 143 bandsaw or someone who could make me one or weld up my damaged one for a reasonable price. Wish I hadn't dropped out of my tool and die apprenticeship in high school sometimes. Oh well.


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## Pathfinder13 (Feb 28, 2014)

sj701 said:


> No problem. I've always enjoyed repairing these Rteks, especially the ones most people would consider too far gone to work on. I haven't used the 515 sealant before so hopefully my methods transfer over, I've always used the Threebond 1211 rtv, I figure if it's good enough to seal cases on my Yamaha waverunner rebuilds, it ought to work on the Rteks, and it has.
> 
> You are correct, everyone has talents, just have to find the one for you...and rely on others for their insight when you need help.
> 
> Now if I could just find a replacement trunnion for my Powermatic 143 bandsaw or someone who could make me one or weld up my damaged one for a reasonable price. Wish I hadn't dropped out of my tool and die apprenticeship in high school sometimes. Oh well.


SJ.. Not sure if this will help ya' but it might.

Powermatic 143 Parts List and Diagram : eReplacementParts.com

That's a nice saw, much better than mine!


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## sj701 (Jan 23, 2014)

Yup item 34 trunnion bracket NLA, but I'll keep looking for awhile.


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## Pathfinder13 (Feb 28, 2014)

sj701 said:


> Yup item 34 trunnion bracket NLA, but I'll keep looking for awhile.


Oh the bracket.. I say go to a local welding shop if you have your old bracket to weld it will be stronger at the weld point than it was before, and cost less too.

btw, I reassembled the engine, letting the sealant cure for couple days even though I used a primer. I am hoping I have enough compression, as I had not way to measure the bore. I took advice and did't go crazy honing but had to get some marks out. Just unsure about precise roundness of the bore. 

If I run amuck on this, I will get an inside mic and check it, to see if this is what caused it as I want to learn why it doesn't run if that ends up being the case. In a couple days after cure, I'll check compression and hopefully have a good engine. I am thinking compression would actually slightly improve as the rings seat in ?

Also, keep your eye on ebay for parts. Amazing what can be found there.


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## Pathfinder13 (Feb 28, 2014)

Just an update.. been letting the case anaerobic sealer cure a few days, so have not worked on this at all. brought the engine into the extra room upstairs and set it on some cardboard so it coud get a couple days of room temperature to cure. 

Today it went back out to the garage, I mounted it back on the frame, mounted the coil with the .010 feeler gage to space it, and after replacing the kit parts on the carb (needle valve, gaskets, shaft seal) I put the carb back on and the governor vane/new spring. Then off to work. 

Will mount the shroud and tank with some fresh gas-mix and see if it fires up tomorrow. I got my fingers crossed. I see no problems that stick out at me right now but this doesn't mean it's going to run .. but I'm hopeful


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## Pathfinder13 (Feb 28, 2014)

Ok .. back together and fired it up, it runs !! 

BUT, I have to hold the governor linkage to idle it down. Now, this is the METAL carb so all the things I have found online look a bit different because they are working on the plastic carb. 

The carb is all clean and the linkage moves freely, I checked the adjustment spec on the governor vane and it's right on the 1 1/4" where it should be from the casting. 

If I hold the linkage it idles down fine, as soon as I let it go it seems that the spring is actually pulling it open and that seems backwards but I have checked over everything and it all looks correct to the illustrations.

so I'm at a loss and wondering if anyone can steer me...


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## sj701 (Jan 23, 2014)

Glad to hear it is running.

It is a single speed setup on those engines. The speed depends on how far you bend the tang that pulls on the spring. Should be set to 4000rpm on the 3650 from factory. So if the governor linkage is free and the air vane isn't damaged it should be good to go. 

There is no easy way on those engines to break it in at a slower speed other than to set the spring to a lower speed then reset back to a higher speed later. I've usually run those engines to operating temp unloaded for about 15 minutes then let it cool to room temp. Next I would run it to operating temp and put it under a load blowing some snow, the higher pressures help seat the rings, then let it cool to room temp.


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## Pathfinder13 (Feb 28, 2014)

OK SJ..so if I can get it to sit there and run at about 4k that's the idle ? Wow. I did put my tach on it and adjusted the tang until it was about 3900, I have not tried any load, ran it for 5 or six minutes while playing with the linkage trying to understand the operation of it, it so simple but is nothing like the 4 stroke carb where you open the throttle with a lever when you are going to work some snow,and turn it down when at rest to idle slower,and then shut it down. 

I double checked the carb, it's weird though as the idle spring pulls from the side that pull s the throttle plate open and the vane when it floats up away from the housing is opposing this spring and closing the throttle plate ? sound right? if that's it I guess I'm good to go, other than a slight surging at no load which I seem to think may subside as the rings seat in. 

I had a bit over 95 on compression test after I ran it a little I'm hoping this improves as the engine seats in. Hoping at least.

This has been a learning experience, I appreciate all the valuable insights.


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## Pathfinder13 (Feb 28, 2014)

This guys engine (when he is backing up ) sounds the same as mine with no load.  I am thinking that since under load when he's going forward it sounds fine, that my rebuild is OK. If there were a problem ( on his machine ) I would think it would run poorly under load. I still wonder why these things were not designed to idle down like a 2 stroke dirt bike. I am thinking possibly one of the crankshaft seals may not be perfect.  If the surging is caused by that, I can replace the seals over the off season 






I never had one of these machines before, always had four-strokes. Seems like great power, but kinda noisy.

So if that guy's machine is "the norm" I think my rebuild is all set.


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## Prof100 (Feb 9, 2015)

Pathfinder13 said:


> Ok .. back together and fired it up, it runs !!
> 
> BUT, I have to hold the governor linkage to idle it down. Now, this is the METAL carb so all the things I have found online look a bit different because they are working on the plastic carb.
> 
> ...


 Congratulations. This has to feel good. I can't help you with the governor issue. That said, well done!

Bill


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## sj701 (Jan 23, 2014)

Pathfinder13 said:


> OK SJ..so if I can get it to sit there and run at about 4k that's the idle ? Wow. I did put my tach on it and adjusted the tang until it was about 3900, I have not tried any load, ran it for 5 or six minutes while playing with the linkage trying to understand the operation of it, it so simple but is nothing like the 4 stroke carb where you open the throttle with a lever when you are going to work some snow,and turn it down when at rest to idle slower,and then shut it down.
> 
> I double checked the carb, it's weird though as the idle spring pulls from the side that pull s the throttle plate open and the vane when it floats up away from the housing is opposing this spring and closing the throttle plate ? sound right? if that's it I guess I'm good to go, other than a slight surging at no load which I seem to think may subside as the rings seat in.
> 
> ...


Sounds like you have the governor setup figured out. Spring pulls throttle open, airflow pushes it shut. So when the engine slows down the air slows down, so the spring pull throttle open to go back to the setpoint, pretty simple. Just one speed however. 

I would expect the compression to come up some after the rings seat.

Toro ran the later model ones pretty lean so some will hunt when unloaded and/or when they are not warmed up, if it doesn't smooth out under load then you need to possibly clean the carb. If yours has a metal carb it is a later one.

Here is a link to one of my videos showing a machine I refurbed and sold last year, you can hear that they never run really smooth until under load.






Again Good job on the rebuild.


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## Pathfinder13 (Feb 28, 2014)

sj701 said:


> Sounds like you have the governor setup figured out. Spring pulls throttle open, airflow pushes it shut. So when the engine slows down the air slows down, so the spring pull throttle open to go back to the setpoint, pretty simple. Just one speed however.
> 
> I would expect the compression to come up some after the rings seat.
> 
> ...


SJ, thank you again as well !! for following the thread and lending your knowledge. I never worked on a two stroke before this one. I have experience on 2 stage machines only until now.

I'll have to re-adjust idle tomorrow but I'm thinking it will even out ok .. I'm optimistic that it's just the spring/tang to get dialed in. I reinstalled the belt so I can shovel a little snow in it's path and give it a light load after the run/cool cycle you suggested.

I may be keeping it for backup or a smaller storm machine if it ends up running decent.  I won't have to start up the 2 stage and it will be faster clearing my smallish driveway using this unless we get dumped on big time and I need to bring out the bigger machine.

Unless of course someone offers enough for it. Might even look for another rtek project in the future, or any one that has the 2.5 inch bore, since now I have a 2.5 hone.

By the way, are there Bobcat parts available anywhere ? I saw a couple this winter on CL but didn't bite not knowing. I used one back in the 80's it was really great to operate and nothing stopped it. I'd like to get one but can't fabricate much, no room for welder, have a wood shop.


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## sj701 (Jan 23, 2014)

Pathfinder13 said:


> SJ, thank you again as well !! for following the thread and lending your knowledge. I never worked on a two stroke before this one. I have experience on 2 stage machines only until now.
> 
> I'll have to re-adjust idle tomorrow but I'm thinking it will even out ok .. I'm optimistic that it's just the spring/tang to get dialed in. I reinstalled the belt so I can shovel a little snow in it's path and give it a light load after the run/cool cycle you suggested.
> 
> ...


Glad you got it back together and going. They are great little machines for quick cleanup and average snowfalls. I use my CCR3650 for most snowfalls. 

Bob cat unique parts are hard to come by. Luckily most of the drive parts are common Browning sprockets and pulleys. The bearings are available but you have to match the sizes up. If you don't like fabbing up parts or buying parts units then I'd pass. They are awesome units but not for everyone.


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## Pathfinder13 (Feb 28, 2014)

Took a quick start up vid after I adjusted the spring/tang for speed, and got the shrouds and chute back on the machine.

Edit: the last shroud (bottom one with curved metal duct around carb) seemed to help things even out, maybe directing additional airflow towards governor vane?

Figured I'd post it even though it's a quick one. By the time I was done, the sun had gone back in and I was real hungry and wanted food so wasted no time 







I am quite happy this is done, need to start a small woodworking project a.s.a.p. I have two weeks to complete that


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## Grunt (Nov 11, 2013)

Sounds great, you did a awesome job on the rebuild.


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## Pathfinder13 (Feb 28, 2014)

Little update . So here's the deal.. since I had found grit upon dissasembling in the open ball bearings on the camshaft,and flushed out real well with PB and oiled up with fresh 2 cycle oil, I do realize the grit had most likely already caused some damage to the bearing and although after I flushed and oiled them..they were once again smooth feeling, but were not under load.

I had not wanted to get into the spending any more than needed, *until* I knew if this engine would run again but now that I know it's running and running decent I am Ok with doing bearings and seals. 

That said, I looked at the parts and found that the bearings come ON the crankshaft as a whole assembly. I found one on ebay last night (seller had only TWO, same seller I had used for the new head gasket, just by chance) and the price was right, jumped on it and purchased brand new crankshaft with bearings for 19.95 shipped. Quite happy with that, as most NEW crankshafts on there I found were 75 bucks at least. Second, went to Jack's Small Engine site and bought the two seals, PTO and Mag for about 4 bucks a piece and some shipping if I remember correct. Don't want to chance these becoming unavailable like many of the rest of the parts. 

So, over the off-season I will split the case, pull the flywheel, and reasemble with new crankshaft and bearings , and fresh seals. The 36 bucks I spent I can assure a long engine life for my new second machine. I was just afraid that if the bearing failed in a year I would not be able to find the parts, or the price would be too high if I did. Grab em' while you can get em' at a good price, right ? You snooze you lose. Someone already scooped the last one on ebay I looked just out of curiosity. Now it's used or pay more.. I just got lucky to find it for 20 bucks new in box. I don't get lucky too often, perhaps I was due


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## classiccat (Mar 1, 2014)

Great find Path! Smart move snatching that up!


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