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Hello Fleetwin,
My company has a good accurate pneumatic gage (I think +/- 0.05 psi). I have verified my compression gage against this gage to be sure my compression gage to be accurate as well. My power head does not show a overheat since there is no discolored on the head and the block. But the head is different color from the block so the previous owner had changed the head! I am very tempting to get this block on the Ebay since it has an impressive 105 psi. Wow it looks like very good compression for 9.5 Hp. It is $75 but the shipping is a killer ($74). I am in Canada and live near the border so I could buy and ship to my friend house in US and just come over on the weekend to pick up. If this power head has truly 105 Psi, should I just swap to mine and will have a good motor for long. What do you think?
Here is the e-bay link
Well, I believe your compression gage more than I believe the ebay ad’s claim of 105PSI! OK, someone replaced your head, probably due to stripped plug threads. Why don’t you go ahead and pull your head and have a look inside. Clean everything up and replace the head gasket, maybe even repaint your head so it matches the original color of your engine. Don’t be afraid to “rough up” the cylinder walls with some crocus cloth/light emery to get rid of the glaze. I know this sounds crude, but we are not dealing with rocket engines here, you won’t harm anything, just clean up the cylinder walls with some WD40 afterwards to get rid of debris. Be sure the cylinder head surface is flat as well.
That ebay powerhead is pretty expensive when you include the shipping, I’m sure it isn’t going anywhere too fast. Changing your powerhead is a pain, you have to pull those lower pans off, which means that many little springs/shims/mounts are going to fall/fly off and hide. I wouldn’t attack this job unless it is truly warranted. OK, so your powerhead isn’t discolored from overheating, although the original head may have been discolored. I suppose the rings could be stuck, or perhaps the walla scored/scuffed from a lack of/wrong oil used. Again, it is best to pull your head and have a closer look if you are concerned.