# hs 724



## rawbertsun (Mar 26, 2018)

Inherited seized up HS 724 from someone who does not know engines need oil. So, freed it up and got it running. Seemed fine until I made a couple of passes in driveway. Then it made a helluva knocking noise. Shut it down quickly. Tore into engine only to discover the connecting rod cap bolts were loose. Tightened them up and engine would barely turn over. Loosened up connecting rod bolts and freed it up.

Soo, these engine have no connecting rod bearings? Didn't see one. Never seen an engine without rod bearings. And, if not, how are you supposed to torque down connecting rod cap bolts without them backing out on their own?


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## tabora (Mar 1, 2017)

I would bet that the con-rod big end has shed some aluminum onto the crank, similar to what is shown in the photos from YSHSfan in the link below. If so, the con-rod needs to be replaced and the crank needs to be cleaned with a lye solution and then polished.

http://www.snowblowerforum.com/forum/1575513-post22.html


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## RedOctobyr (Mar 2, 2014)

Welcome to the forum! tabora's suggestion would be my thought as well, material transferring onto the crankshaft, creating an interference with the connecting rod, when the bolts are tight. 

If parts were going to be really expensive, or something else was damaged, you could also look into an engine swap. Harbor Freight's Predator engines (Honda clones) are popular here, the 212cc engine is frequently on sale for around $100. It looks like the HS 724 came with a 200cc engine, so you might even gain a bit of performance, if you did a swap.


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## rawbertsun (Mar 26, 2018)

Wow! Thanks for quick replies. I think Predator just might be the solution. Never knew that.

Still curious about connecting rod. So, no bearings? And, if torqued correctly, connecting rod end just rides on crankshaft journal? How is it that rod cap bolts backed out by themselves?


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## YSHSfan (Jun 25, 2014)

Yes, no bearing there.

It is kind of designed 'on purpose' that way so that the rod is the sacrificial part and the crank can be saved.

I have 2 GX240 engines on the bench which had thrown rods. I cleaned the aluminum with a strong lye solution and polish them with 420 sand paper soaked in wd40 or diesel (you turn the sand paper using a shoelace to keep from getting high spots).

In my case I am likely turning the GX240 into GX270 with a few upgrades I'll start with one and if it works I'll do the same with the other one.

Rod is ~$20 and you'll need a few gaskets/seals, not really an expensive repair if you do the work.

If you go the predator way, you'll need to shim the 20mm pulleys to fit the 3/4" predator shaft.

:blowerhug:


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## tabora (Mar 1, 2017)

RedOctobyr said:


> If parts were going to be really expensive...


The whole connecting rod assembly is available from China (on eBay) for under $5 with free shipping, if you can wait a few weeks for delivery.

https://www.ebay.com/itm/Connecting...394425?hash=item4b2fda79f9:g:ZB4AAOSw8axaJ8sK


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## Kiss4aFrog (Nov 3, 2013)

:welcome: to SBF rawbertsun

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## arienskids (Jan 26, 2018)

you have two options, you can either clean the crankshaft with muriatic acid and replace the rod but if you go that route you will have to replace the sump gasket, head gasket and valve cover gasket and you may as well hone out the cylinder and install new rings if your going to have it down that far anyways, and it will run you 30 bucks for the whole kit plus you will need a cylinder hone. all in all, youll probably have 60 bucks into this engine at least. if it were me, i would just go with a new predator 212 hemi and be done with it.

https://www.harborfreight.com/4-inch-engine-cylinder-hone-97164.html

https://www.ebay.com/itm/New-Piston...903967?hash=item1c344334df:g:NlgAAOSwt4xacMog


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## YSHSfan (Jun 25, 2014)

If it was a GX160 I'd say go for the predator, but having a GX200 I'd fix it.

If you go the predator way you'll have to shim the 20mm pulley to fit to the 3/4 shaft on the predator, make some kind of snow shielding (or transfer the shields from the GX200, may be a perfect fit) to turn it into a 'winter dressed engine', probably re-jet it and most importantly you WILL NOT have a charge/light coil on the predator (you won't be able to fit a light to the snowblower or connect the one that's there if fitted).


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## rawbertsun (Mar 26, 2018)

Thanks everyone. Got the Predator. $111 at HF. About shimming. Shim stock? Ready made piece? Old tin can?


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## arienskids (Jan 26, 2018)

next step is to pull your pulleys off and match them at tractor supply. then its pretty much just drop the engine on and run it at that point


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## Kiss4aFrog (Nov 3, 2013)

I'm not the Honda expert but from what I can find it looks like you'd either need to have the pulley bored out to 7/8" or 1" since it's 20mm and that's just a bit over .75" or just do your best at measuring the OD of the stock pulley and purchasing a replacement.

OMBwarehouse, maybe in stock at menards, fleet farm, tractor supply ... Minibike or go kart on line shops. 

Clutch & Drive Pulley | BMI Karts and Parts
Go Kart Drive Belt | Go Kart Belt Drive | Go Kart Drive Belts
https://www.ombwarehouse.com/

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## YSHSfan (Jun 25, 2014)

Kiss4aFrog said:


> I'm not the Honda expert but from what I can find it looks like you'd either need to have the pulley bored out to 7/8" or 1" since it's 20mm and that's just a bit over .75"


I agree, getting bored out to 7/8" or 1" and getting a sleeve kit. This will keep the pulleys in perfect alignment (they could also be welded and bored to 3/4").
I tried once installing a very thin flashing 'shim' from 3/4" to 20mm but I was not happy with the result (the pulleys did not centered perfectly and at 3600rpm that's not a good idea lain.


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