3.5HP Tecumseh on a Chipper/Shredder

[itsgalf]

Hello all, I'm trying to fix up a Chipper/Shredder where the compression is very low (35 psi). Tecumseh H35-45696S
I lapped the valves and shaved off a little from the exhaust valve to get the proper valve clearance. Still low compression.
I put some engine oil down the spark plug hole to perform a wet compression test (probably should have done this first - still learning) and compression rose to about 80 psi.
Looks like a piston ring job. Never done one before - hopefully I can tackle it.

Now the problem is getting the shredder impeller off of the shaft so I can dismount the engine to work on it. Looks like I need a large puller. Any one with good tips?
Model: MTD 242-640-000

 

[dougand3]

Guessing here...any secure place to hook an 8-12" puller? Parts stores have them as loaner tools.
Ring sets...the few times I looked up buying them for 4-6 hp mower engines, they were ~$40. Phhhfffsttt. I found mowers with carb problems for $20 and mounted them.

 

[Scrubcadet10]

OEM piston rings are no longer made, or available according to the 5 online part stores I visited.
But Jack's small engines said that these will fit, made by Stens,https://www.jackssmallengines.com/jacks-parts-lookup/part/universal/500306

 

[bertsmobile1]

That is a no nonsense looking piece of kit.
To remove the rotor use the same method as removing a stuck wheel
Start with multiple heating cycles, heat it very hot then cool with water spray
Towards the end, let it cool a bit slower then when about 200 deg ( just too hot to touch spray your favourite penetrant around the shaft.
Repeat this a few times

Now apply some pressure to the rotor , pry bars, wedges etc and with this applied hit the crank shaft .
An air hammer works best
As it moves make sure you keep up the pulling pressure on the rotor.
A two person job if you are using pry bars.

When you get it off, some never seize is a good idea & try to remember to pull it off every few years.

 

[Fish]

Have you tried to start the engine?


Compression readings on small engines are not very accurate..

 

[itsgalf]

Thanks for the responses. Should be fun

I have tried to start it. Good spark and clean carburetor. Even used some carb cleaner in the spark plug hole before pulling it over. Still couldn't get it going.
I realize there's a compression release mechanism, but doing the wet compression test led to a noticeably higher compression reading - so should be the rings I think