Farm Equipment - 3.5 hp.Tecumseh engine ?

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3.5 hp.Tecumseh engine ?

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Topic: 3.5 hp.Tecumseh engine ?

Posted By: Bob (mo)
Subject: 3.5 hp.Tecumseh engine ?
Date Posted: 21 Apr 2011 at 12:59am

My 3.5 hp Tecumseh motor on my Troy Bilt tiller threw a rod . What i need to know is- will the cam out of my 3.5 hp Tecumseh work in a 5 hp. Tecumseh ? I have found a 5 hp. Tecumseh that i can get pretty cheap but it does not have the extended cam shaft that runs the reverse . That is why i need to switch cams.Thanks for any advise you can give me

Replies:

Posted By: scott
Date Posted: 21 Apr 2011 at 6:15am

Dont forget to count the teeth on the gear. I swapped cams into a minibike years ago, put a penny in the clutch and went to pushing. She'd fire off once in about ten feet of push when everything lined up just right. If I remember right I did the opposite and cut a long cam to fit in where a short cam came from.

Posted By: Orange Blood
Date Posted: 21 Apr 2011 at 6:25am

I'd say you are going to have to do some measuring, and what about the cranckcase cover, I am guessing the new one, will not have the opening for the cam, or a place for a seal?

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Posted By: jaybmiller
Date Posted: 21 Apr 2011 at 6:33am

Your question is one reason why I like B&S over Tec! B&S have all the illustrated parts manuals online, easy to download, Tec doesn't(trys to keep them secret !).When I need to make sure 'does A fit into B', I jsut grab both B&S manuals.

For Tec, you might try going to http://www.partstree.com - www.partstree.com , enter in Tecumseh then the model number, but you have to have both engine model numbers.Once 'in' lookup the part,find the number, then compare to the other engine.Might take 10,15 minutes but time well spent.My 'gut' feeling says they'll be the same...but... good luck.

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Posted By: Dakota Dave
Date Posted: 21 Apr 2011 at 8:12am

Go to a small engine shop a Tecumsech short block should be pretty cheap. they even come with a new head gasket. all you do is swap over you head, carb , exhaust, flywheel and shrouding. you'll need all the numbers off the tag

Posted By: DonDittmar
Date Posted: 21 Apr 2011 at 8:25am

www.smallenginewarehouse.com

Just buy a new motor, sure will save some time

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Posted By: Bob (mo)
Date Posted: 21 Apr 2011 at 11:27am

Time i have, money i dont. The 5 hp.motors i am looking at on ebay are new .From what i can tell from pictures it looks like the new motors have a plug in cam hole and also from what ive seen it looks like the covers will interchange.

Posted By: Gerald J.
Date Posted: 21 Apr 2011 at 11:55am

You think the cam gears for driving the cam alone are as sturdy as the gears for taking load off the cam? I don't. Cam alone may take a quarter hp while load on the cam shaft for the tiller could have to handle the whole engine horsepower. Makes for a lot thicker gears and a thicker cam shaft. Seeing as how Tecumseh's have no spare metal in the rest of the engine (especially the connecting rod cap and bolts) its unlikely the cam gears for a normal engine will be sturdy enough for full load on the cam shaft when the engine has that option.

Gerald J.

Posted By: Brian Jasper co. Ia
Date Posted: 21 Apr 2011 at 11:59am

Depends on which model of 5hp Tecumseh you're looking at. You probably have an H35 for the 3.5 eng. If it's going to work at all, you need an H50. There is also an HM50 that is like comparing a big block to a small block. Another difference is some of the H50's have the intake and exhaust ports reversed compared to the H35.

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