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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

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.

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

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.

Have you tried to start the engine?


Compression readings on small engines are not very accurate..

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