# Tecumseh H50 carb - studs stripped, spinning



## tlshawks (Feb 9, 2018)

Crud. Figured someone here knows a trick I'm not thinking of yet.

So, I'm trying to remove a carb on a 910965 Ariens, H50 Tec. The nuts for the carb are both spinning the studs, yet the studs are not backing out as I spin the nut with a wrench. I can't help but think the stud or manifold threads got rusty to the point where they don't thread at all any more.

This is a roughly 1971-2 engine, and the previous owner probably hadn't removed the carb in a long, long time. It sat unused for over a decade and overall the blower is in fantastic cosmetic shape, zero rust anywhere. Just ain't been used in a long time.

To me, I have to get some sort of leverage on the carb assembly to pull as I turn, but there isn't room to really apply any pulling force. The two manifold Phillips screws, I can get at one but not the other.

To me, if I can get the studs to start coming out away from the manifold, I can save these all without needing a replacement manifold or tapping new threads etc (hopefully).

So...what trick am I missing here?


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## tadawson (Jan 3, 2018)

Does that engine have the small intermediate manifold between the carb and the block, as in the H70? If so, then there are two sets of bolts - the ones attaching the carb to the small manifold (which are actually loose bolts that it in a recess in the back of the manifold) and also Phillips headed bolts, iirc, that attach the manifold to the block . . . (I think on mine, the star washers were behind the bolt heads, and not the nuts, which may explain why yours spin . . .).

- Tim


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## Jackmels (Feb 18, 2013)

Fuel inlet Interferes w/The RH Screw. A Long Thin Screwdriver is what you need to get in there. A little Heat Wouldn't hurt, as long as there's no Gas Present. GL.


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## tlshawks (Feb 9, 2018)

Yes, the H50 appears at a glance to be exactly like an H70 in how the carb is mounted.

That second manifold screw, the right side one - that's an acute angle all right. I admit, I didn't try a smaller Phillips because of the large Phillips heads those two have. I needed the largest head Phillips screwdriver I had to get the left one loose. 

I'm afraid I'll strip the right side screw - but I'm beginning to think I have no other choice but to at least try it.



Edit - I tried heating it up, still no go. With the proper tipped screwdriver, I cannot get enough torque to turn the screw and endanger stripping the head. With a smaller tipped driver, doesn't hold at all.

All I can think of is somehow cutting the nuts off between the nut and carb mounting base - appears there's star washers between the nuts and carb. It'll mean I'll need new studs and if the manifold threads are bad, maybe that too. This is what I was hoping to avoid - tearing up effectively everything that bolts to the block itself just to remove the carb.

Sigh...frustrating.


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## JLawrence08648 (Jan 15, 2017)

Of course penetrating oil, several times a day, then for a few days, maybe different brands, can try a mix of alcohol and auto trans fluid.

Also take the large Phillips and bang it with a hammer as an impact wrench. Also can try an impact wrench, the banging may work.


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## classiccat (Mar 1, 2014)

You're on the right track trying to remove the entire carb/manifold assy from the block.

If I recall for the stubborn ones (specifically the one on the right), I've used a #2 driver bit, put some inward pressure on it using a large screwdriver leveraged against the fuel inlet, then turn the bit with a 1/4" open-ended wrench. The L/S screw should be a straight shot with a long screwdriver.


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## JLawrence08648 (Jan 15, 2017)

On occasion I've had a carb where the machine screws were tough and I was going to strip the Phillips head of the screw. I took the manifold off the engine and being in the bench and the rear being more accessible, I was able to put a vise grip on the screw head and a wrench on the nut.


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## Jackmels (Feb 18, 2013)

Chisel the Aluminum Manifold Off. I'll send You a Replacement for cost of Postage.


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## Lottstodo (Feb 16, 2018)

For screws that are hard to get anything into and not moving what I have done on many occasions is take 1 of my old long drift punches that I have ground one side at a 45 degree angle and using the sharp side go to the top left side of the screw and start tapping the drift in a manner that lets it start to bite into the screw ledge and when it has a decent perch then increase hammer hit pressure(not wail or beat) and most times it will spin the bolt or screw. I prefer the the round drifts not only for the length but as well for the rounded cutting edge that you get after grinding , this gives you a high center point on the edge can be relocated in a very small area for max bite/ grip. I do like these instead of chisels just for room and having the edge closer to the center of the punch, so you have more control. I have picked up many drifts at yard sales etc and even hardware dollar sales and now have a complete set from 1/8 " up to 3/8" ground only for this purpose .


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## tlshawks (Feb 9, 2018)

classiccat said:


> You're on the right track trying to remove the entire carb/manifold assy from the block.
> 
> If I recall for the stubborn ones (specifically the one on the right), I've used a #2 driver bit, put some inward pressure on it using a large screwdriver leveraged against the fuel inlet, then turn the bit with a 1/4" open-ended wrench. The L/S screw should be a straight shot with a long screwdriver.


I've been thinking along these lines, either doing this or an angled screwdriver. Waiting for tomorrow when it's 20 degrees warmer.

Jack, I get the feeling I'm going to need your help in a replacement manifold with studs no matter what. I'll post back after I give this issue the ol' college try.


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## Vermont007 (Mar 29, 2015)

Assuming you get the studs out, let me recommend the insertion of a HeliCoil (stainless steel) so that you can use the same size studs, or maybe a bolt with the same thread.

The engineers must have used studs originally because it's tapped into aluminum and was expected that the manifold would have to be removed and reinstalled multiple times over the life of the engine . . . . and the aluminum threads would be ruined over time.


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## tlshawks (Feb 9, 2018)

Well, well, well - my schedule cleared for a couple hours, so I pulled out the ol' college try, and failed... yet succeeded.

I wound up being able to move the screw a bit, but stripped it in the process to where it would move no more. So, tired of wasting time, I got out the Dremel and cut the carb bolts off, which went surprisingly easy.

However, once I extracted the manifold screws, lookie what I found. This is looking from the backside of the manifold. No friggin' wonder the studs were turning. They ain't really studs, at least what I'd call studs.

I'm at a loss what to do now. To me, mounted this way, you have to mount the carb and manifold together, then mount the assembly, odd angle and all.


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## tlshawks (Feb 9, 2018)

And here's what I can't figure out. I have an Ariens with an exact same vintage H70. Didn't have a single issue pulling the carb off that machine. I have to assume they have the same manifold design.

How did they keep the screw studs from turning?


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## Lottstodo (Feb 16, 2018)

I have taken JB weld high temp extreme 2400 F cleaned up those screw pockets and roughed up (dremel works nice ) then start on backside fill with mixed epoxy toothpick to make sure voids are filled then put on wax paper and finish outer. this stuff can be milled , machined, and tapped for threads, so you can either use bolt from the outside going in or once tapped thread stud with loctite and use nuts there is not much torque required for assembly this has worked really well on old cumcys briggs and kolher unless you are doing restoration and want to keep it original. by the way the JB extreme high temp comes in a small bottle and all you do is mix contents in that same bottle and use. I purchased at auto store around $8.50 the contents are 1 time use so you have to mix the entire bottle at 1 time. maybe 1oz I think.


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## tlshawks (Feb 9, 2018)

OK...more investigating.

Tecumseh part 34712 appears to be the part this manifold is, at least the modern equivalent. When I google that, Ebay has a NOS with mounting screws. The stud openings are threaded. Unfortunately, those studs/nuts aren't included. Ideally, that is what I would believe would be the best working option, with the studs that fit the threads (cannot figure out what their part # is) as well as the flange gasket and carb nuts. 

To me, there's a reason why they went to this design. It appears to be my ideal fix.

I see also, 30195A and 30195 (prior part #'s). I see the carb screws have star washers on them, which must be what holds that screw stud in place when tightened. This must be what I actually have on this machine.

My flange/manifold (official Tecumseh term is carburetor flange) is in good shape, but obviously the star lock washers aren't (in addition to needing new screws too).


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## Jackmels (Feb 18, 2013)

This is one I have. PM Sent.


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## tlshawks (Feb 9, 2018)

Welp...success!

I was finally able to get to work on this ol' girl this morning, and it me tell you - it was an odyssey.

Of note, for anybody having to go to a Tecumseh carb flange #34712, you better hope the correct screws/bolts/studs etc are with it - because it certainly was interesting figuring out what it needs.

I wound up having to buy 1/4"-20 x 3/4" bolts and mount the carb from the outside instead of with either screws that were 1/4"-28 x 1 1/4 (which is what 30195/A uses) - or possibly a real honest to goodness Tecumseh part that is meant for the 34712. 

When you look up any Tecumseh engine that uses this flange (such as the H50/60/70), the parts lookup for the original flange 30195 or 30195A will state "replaced by 34712", but the mounting screws, it still states are 650572...which are the old screws/star washers - these go along with the original star nuts that pair with them and mount from the engine side of the older flange.

Anyway...


Just got everything put back together, carb fully rebuilt (black gunk on the carb and bowl, like gas sat in it a long time) - But it started first pull, woo hoo! Aside from it not wanting to shut down on the throttle very well - but it does shut off - it ran like a champ. The choke and throttle butterflies are still a tad sticky (throttle butterfly/spring doesn't seem to be strong enough to push it all the way closed), and the jets will need some slight tweaking...but otherwise, ran very nice. Ran new hoses, got the proper hose clamps, etc...tank looks perfectly rust free on the inside too.

So...bought this machine on the cheap - it's been repainted "decently" and is rust free (awesome 10 footer), but it was bought as a non runner. Judging from the looseness of the carb box and how freely the carb mounting bolts were, looked to me like the prior owner or a shop tried to fix it, discovered the issues, told the owner it wasn't worth fixing - and he listed it on CL! The ad was 2 months old.

Heck, I bought it for the rust free parts for my 910962 more than anything. The hardest part outside of the research was using those bolts instead of screws/nuts...getting them to start threading on the flange while keeping the gasket/carb/throttle cable/lever assembly all in line. Being outside...my cold, chubby old man fingers just didn't have very good feel nor room to start threading them easily, but once they were started, everything bolted together nicely.

I got maybe tops $25 in parts in it...runs like a champ, all gears shift smoothly, auger turns quietly. An amazingly clean machine overall. 

Maybe I should load it up, drive up north to SE Minnesota/NE Iowa - and be a nice guy and plow someone's snow with it tomorrow morning  Who knows, maybe this storm will drop south and dump on us (but I doubt it).


Anyway, thanks for all the help/suggestions...absolutely LOVE this website. Pictures to come on the Ariens forum once the weather cooperates (raining off/on at the moment, more coming) and all carb adjustments/re-assembly are sorted out.


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## tadawson (Jan 3, 2018)

If you have not done so already, hit the throttle plate shaft and spring with some carb cleaner. Between the shaft and spring, they tend to get gunky and stick, and typically will free up with a shot of cleaner and working it a bit. 

- Tim


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## tlshawks (Feb 9, 2018)

Yep, Tim. I have. Certainly loosened up some. I rebuilt the carb last week and it was free after really working the shaft and spring with cleaner.

When I rebuilt it, there was a layer of black scum along the bottom of the carb venturi as you look at it, like gas leaked out over time and sat there for years on end. This is obviously where the bottom part of the shaft mounts. The spring also had some of the black gunk/rust on it too, but I can't spray any more carb cleaner on that, I soaked it thoroughly...it has to be clean enough. I just believe a lot of gunk settled at the bottom pivot of the shaft and for whatever reason doesn't want to come out easily.

This morning, inside my house nice and warm, the butterfly worked fine - turned it open several times, closed 100% on it's own quickly every time. Took it outside into 35 degree weather...firmed up some to where the springs wouldn't return it completely all the time.

I may wind up taking it off again and removing the butterfly and shaft (regretting not doing that when I had the chance the 1st time), for there seems to be a lot of gunk still on that shaft that refuses to come out.

I thought about buying a Chinese carb for it...but I just like to use OEM if I can and rebuild things. It runs fantastic, no popping, no surging, etc. Just doesn't always want to close properly to shut down. I suppose I could merely turn the gas line valve closed if it ever hung up with the carb box on.

I'll figure it out.


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## tadawson (Jan 3, 2018)

Understood. Seems like every time I have an old carb that has sat for a while, that gets sticky . . . . and apparently, I am lucky . . . mine seem to free up well, even an H70 that sat with fuel in it for 15+ years . . . And I agree - I like the OEM/original carbs as long as there is no physical damage, they seem to clean up and run well.


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## tlshawks (Feb 9, 2018)

Welp, got 'er dialed in. Idle jet and main jet adjusted to where she runs perfect at WOT and slow idle, and she shuts off reliably enough now. I wound up taking the "primer" assembly off my '962's carb because someone at some point bent the heck out of the primer frame on this one. So now she looks stock as can be (cold starts fine without it).

Gonna need an oil change, glad I checked it, she's low though with what appears to be barely used oil - so just gonna change it when the weather's warmer when I can do all 3 of my old school Ariens together. Gonna need a bath then too, still a bit dusty/cobwebby and a small layer of "ain't been washed in a while". She's too good looking to not get a bath!

But I gave her a run around the yard to test all the gears etc...ran very nicely, doesn't surge ever, and zero popping. And now that I know what one of these is supposed to shift like (trans case schematics appear to be very similar), I should be able to compare this to my 910962 to see what the hangup is with that one going from R/N/F.

Total impulse buy, too nice and inexpensive to pass up, less than $100 total invested - Project My First Resuscitation is complete, woo hoo!

feelsgoodman.jpg


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## baddevil007 (Feb 14, 2019)

Thankyou so much for putting this bolt size in the forum thread. I could not find the size bolts needed to mount the carb on my Tecumseh oh50 power sport engine for my vintage gokart anywhere else. You guys rock! size: 1/4"-20 x 3/4"


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## Eng-Sol (19 d ago)

With more than 30 years in engineering, this has got to be one of the worst examples of poor design I have ever seen. There are so many other ways to have done this than blind sub bolts hiding behind an adapter held on with BLIND Philips screws hiding behind a bracket, as steel fasteners into high temp aluminum head. If this isn't planned obsolescence I don't know what is. Was this Tecumseh or Ariens or both working together to create this folly?

I used a cut off wheel to chop the fuel inlet barb off then Dremeled it flush carefully. Then dremel ground a true path in the bracket to increase the path to the Philips in order to use an impact driver with Philips bit. This can avoid the loss of the adapter at the head and the bracket. Once off it's easier to handle the two hidden bolts that were trapped between the adapters.

Most surprising of all there appears to be no real reason this design was used. If it was simply to stand off the carb further from the head, they could have simply used a thicker, single adapter given the machining / casting requirements wouldn't have been any more costly than the mess they made.

My Ariens lawn mower also has it's share of high school engineering on it as well, albeit it has outlasted two of my neighbor's John Deer mowers over 15 years time and leaves a better cut. Go figure.

Good luck to others.

Mike

*Edit... Option #2*, to avoid damaging the inlet nipple, it's possible to drill a 1/16 inch hole in the outer most adapter flange directly above the right hand blind bolt buried between the outer and inner adapters. The drill will intersect the blind bolt, at which point I used a dremel ball nose burr to indent the blind bolt. I then put the shank end of the drill bit into the drilled hole to intersect the blind bolt, holding it firm, while threading off the hex nut, (leaving the phillips screw untouched). Next, I pried down on the throttle bracket above the left most blind bolt, which provided enough resistance to the left blind bolt to remove the left side hex nut, (again without concern of the Phillips screw behind there).

This method leaves the inner most adapter fixed in place to the head, while the carb slips off the blind bolts. With the carb out of the way, one can approach the Philips screws reliably. Removing the inner most adapter lets one tighten the blind bolts properly when reinstalling the adapters after cleaning up or replacing the carb.

Personally I chose to bore the 1/16 hole through each of the left and right adapater ears and bolts intersecting cross sections in order to never face dealing with the Philips screws. On reassembly, I just lined up the hole in the bolt and adapter, placed the 1/16 bit through the adapter hole to again hold the bolt, while tightening the hex nuts sufficiently to seal. I did use a very thin smear of RTV in order to assure gasket seal without having to over-tighten the nuts. 

Hope this might help someone facing this awkward design debacle along side the other good suggestions on the thread.

Mike

*Final edit - fuel inlet nipple: *The fuel inlet nipple on most of these will be a press fitted nipple. For those who chose to sacrifice the inlet nipple, once the carb is off the machine, the remaining nipple can be dremeled flat, tapped and pulled. Carefully tap the remaining slug, place a socket over the nipple ares just large enough to clear the stub to pull out. Thread a bolt with nut and washer through the socket until the bolt just snugs at bottom. Run the nut and washer down onto the socket and continue to tighten the nut as a "puller" to ease the nipple slug out of it's pressed fit. It may be helpful to warm the carb around the nipple slightly with a butane lighter to about 200 degrees F to help relax the press fit just before tightening the nut / washer to begin pulling. Don't overheat the carb in doing so as these are soft, cast metals. If a drop of water boils where heated, you've reached 200 degrees.

The nipple slug may give way with a slight "snap" when it first gives, hopefully that the tapped threads hold up to the effort. If this effort fails, the remaining option is to drill out the remaining press fit. I chose to use a steel barb fitting to replace the prior nipple having the benefit of a lathe to turn off the threads of the barb fitting to the press fit dimension. *DO NOT use a brass fitting for this*. The aluminum will break down in reaction to brass over time and fail.

*Phillips screws in the head:* Once the carb is off one can use penetrant and an impact method to try removing the phillips screws. If this fails you at least have access now to drill the screw heads out until only the bolt shank remains, allowing the adapter to come off the head, leaving the shanks behind. A good set of locking pliars on the shank should suffice to twist the shanks out of the head. Warming the head with a torch would be a good idea, especially if you find an auto store that carries CRC freeze spray to chill the bolt after warming the head.

Mike


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## laser3kw (Feb 11, 2018)

LOL - I got sucked in again! I didn't notice that this is a 4 year old thread and started reading and responding to others comments.
Well, anyway - Merry Christmas


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