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Tecumseh HM80 Compatibility Question


PvtPoverty's Avatar
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08-26-08, 09:03 AM   #1  
Tecumseh HM80 Compatibility Question

I have a Sears Craftsman 8/25 Trac-Drive circa mid 80's with a Tecumseh HM80-155321L engine. The connecting rod is broken and the crankshaft appears to be scored. I have the owners manual complete with an exploded view and part numbers of the engine.

My question is, before I order the parts to rebuild it, I found an 8hp Tecumseh on Craigslist that appears to be identical except for the additional pto from the camshaft which mine has.

http://cleveland.craigslist.org/grd/786886457.html

1.) Will this engine work for me as is?

2.) Can I use my camshaft and cover on it so it becomes dual pto?

From the research I've done so far on this site, it appears that the only function for the second pto is to drive the reverse gears. (I can live without reverse if it saves me a few $'s)

Also, he says he has a buyer for the starter which could offset the $75 he is asking. (I would sell mine)

 
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30yearTech's Avatar
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08-26-08, 11:13 AM   #2  
If they are both HM80 model engines then most of the basic components will be interchangeable. The engines may have a different crankshaft then yours. While the bolt pattern on the sump will be the same, it may or may not work depending on whether the sump will fit the crankshaft thats in the engine.

Does this clear anything up, or just add to the confusion??

 
smallengineguy's Avatar
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08-26-08, 12:50 PM   #3  
Start with the simple things 1st. The engine you are looking to buy has a 1" crankshaft. If you want to use you cylinder cover, your crank must be a 1" also, some HM80's are only 3/4". If you have a 1: crankshaft see if you can get the engine numbers from the person selling it and maybe we can research further for you.

 
PvtPoverty's Avatar
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08-26-08, 02:04 PM   #4  
Thank you both. I was there to see his but I didn't know where to look for the numbers. I know mine from the owners manual.

I just mic'd the shafts on mine and it's 3/4" and 5/8" for the aux. pto. The part of the main shaft that goes through the cover is 1.25" though. ???

Edit: I just got off the phone with him and it might be sold tonight.

Where do you recommend I buy parts from?

Thanks.


Last edited by PvtPoverty; 08-26-08 at 02:19 PM. Reason: Additional information
 
smallengineguy's Avatar
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08-26-08, 02:55 PM   #5  
The connecting rod for your engine is listed as NLA, the crankshaft is $110. Crank can usually be cleaned up with muriatic acid. It is most likely not "scored" just has some aluminum transfer on it. I would 1st ask if you checked your block behind your electric starter to be sure it is not cracked or have a hole in it. This is where the rod usually hits. This would rule out repairing your engine. It does not sound like the cylinder cover from your engine is going to work. As far as using that engine and forgoing reverse you will also have a problem because your engine pulley is for a 3/4" crankshaft so you cannot use it on other engine (1" crank) You would need a new pulley and they run $40-$50 unless you can find a used one.

Best to find a used engine with a 3/4" crank and a pto shaft. It needs not be an HM80, it could be a HMSK80 or a H70. They will all bolt right on. You could even go with a Briggs but may run into a few other minor issues. y sticking with a 3/4" crank and using your pulley, your belts will also work. At $15-$20 a pop that becomes a factor also.

 
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