140 hp Johnson

[phatdaddy]

hard to believe it ran at all with those #'s. when it died, did it bog down or was it like your key was turned off. when you attempted to restart did it spin freely or was it binding and sounded like the battery was weak.
i'd pull the heads and look in the cylinders anyway, easy to do and nothing to lose.

[smokeonthewater]

Did you do the compression test with a fully charged battery and at full throttle?
And um yes.... Time to find a new engine

[shurlock]

tried the compression tests turning it by hand, I also tried the compression test using the starter motor from the engine. I tried the compression test with the motor advanced and also with the throttle open.I even tried removing the Schrader valve thinking there was a restriction. all the same. I purchased the service manual for the Johnson. will read it and pull one of the heads tomorrow and let you know what I see. "spareparts" I am looking forward to hearing from you. "Spareparts" seemed very knowledgeable about the engine wish I followed compression test first.

[shurlock]

By the way guys just wanted to let you all know, bought the boat next day went out for sea trial. start it up first crank it jumped to life, then ran almost a mile at WOT Then died like I turned off the key. feeling guilty that maybe I should have drained gas, and started new. by the way almost 3 a.m. Here in Florida had a few to drink !!!

[THEFERMANATOR]

Compression should be roughly 140-150 for a 140 looper. Small bore and big bore V4's both ran pretty high compression. Most likely you put the screws to it with bad fuel and leaned it out. Loopers HATE being run lean, and will smear the pistons in a HURRY. It only takes an overheat for about 15 seconds to smear a piston in one. They are AWESOME engines when setup and running right, but one little problem and they will self destruct in a matter of seconds. The T-stats and bypass valve can also cause this to happen. You want the engien to idle at about 150-170 degrees, but at WOT you want it to drop back to about 125 to keep from sticking a piston.

[spareparts]

Ferm and Skools Out are the looper experts around here.But sounds like your motor is dead. If you want to eliminate another variable, try your compression tester in another engine to make sure its reading correctly or try another compression tester on your engine. Next step, pull the heads and take a look.

[shurlock]

opened it up walls of the cylinder are very scored. here is a picture. looks like motor was never properly flushed out heavy corrosion.