35EL78R question about loss of power

[wglanville]

I currently have a 74 25hp short shaft, and I have the opportunity to buy a 78 35hp long shaft, (which I need). I can get it for $300 because current owner says it needs new rings. Compression numbers are 130 on upper and 122 on lower... Pretty good numbers right?. Could rings be bad with those compression numbers?. His reasoning is lack of power. He said it takes a long time to get up on plane on his 15' aluminum boat.

Spun prop maybe?. What else would cause loads of power like that?. What would it cost approximately, if I needed new rings?

This site has helped a lot in the past, hopefully it comes through again, thanks I advance for the advise.

 

[bonz_d]

Comp numbers aren't to far off. Could be a head gasket. Did you check that one more than once? Power loss could be from dropping spark on one cylinder. Can try running a tach on it to see if it's getting up to RPM range. Should be 5000 to 5500rpm at WOT. At this point I'd try a drop test on it while it's running to see if it's losing spark.

If the prop was spun it would rev high and not go anywhere.

 

[wglanville]

With decent compression numbers, is it worth taking a risk on it, or should I walk away?

 

[David Young]

It Seems to be a good motor. Maybe just needs a tuneup and a carb rebuild. Don't tell the seller that, maybe he'll go down on the price a little.

 

[bonz_d]

With decent compression numbers, is it worth taking a risk on it, or should I walk away?

That's a judgment call you're going to have to make. I watch the La Crosse CL along with most of the state pretty regularly. I think you can find better for just a bit more money! Example, Just picked up a 1994 30hp in Oshkosh for $325.00, cleaned carb and installed a new water pump and it runs great. Also there is a person in the Twin Cities with a newer 35hp that is asking $400.00 for it.

If it were me I'd keep looking.