140 hp Johnson

shurlock

shurlock

Member
my brand new boat failed first day out ran balls to the wall for the first 20 minutes got about 1 mile out and she died I have Spark and am getting gas any ideas on this engine. it is the original gas that I bought the boat with possible bad gas? but then I don't know why it would run for 20 minutes.
 
start with a compression test. Then take a fuel sample. Pull the fuel line off, squeeze the primer bulb and let some fill a jar or clear jug. Come back with a report of compression and condition of the gas
 
ok I dont know 1/3 as much as these guys on this site but first thing i would check is the water sepperator filter if you have one, take it off and dump the fuel in a glass jar to see if theres water in it and dont reuse the filter put on a new one if you have a water sepperator thats the first thing i would check, could also be a stator but i dont know how to check it . the way i checked mine is i took it to my mechanic and he checked it and replaced it 300 dollars later
 
Help

ok everyone removed fuel seporator and everything looked good. just to be on the safe side got a new small tank of mix gas removed bowl drains on all four carburators. i pumped untill fresh gas came out, put it all back together and attemped to start. NOTHING. now this is where it gets scary got compression tester and as follows:
#1 @ 30 psi
#2 @ 29 psi
#3 @ 0 psi
#4 @ 30 psi

AM I REALLY SCREWED HERE?
 
I say yes...Sorry to see that. The numbers should be around 90-115 ( could be as high as 140) or so range and no more than a 10 psi variance
 
Dam, Sorry to see that Shurlock.

At least you know where you stand with it though. Sometimes I'd rather it be completley dead though rather just hanging on, causing you to spend more money on an old engine.
 
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.
 
I thought so

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

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actually corrosion doesn't look that bad for a 20 something year old engine ran in salt water.
just one scored cyl or were they all harmed? are you sure the gas had oil in it?
 
the Pistons walls were just scored not hammered not sure if the previous owner had oil in it I know the VRO was disconnected and he said he was using Mix
 
spare, is that lack of oil or overheat?
shurlock, i said harmed, not hammered, was wondering if all cyl looked the same
 
phatdaddy said:
spare, is that lack of oil or overheat?
shurlock, i said harmed, not hammered, was wondering if all cyl looked the same
Click to expand...

Look at the pistom dome, that engine LEANED OUT BAD! theres not even a trace of black carbon or soot on it. A looper should always have some sort of soot on the piston dome when they are jetted to live, and there should be some traces of wetness.

Looking at your pics it looks like a small bore engine which were ALWAYS prone to overheating due to there design. Where are you located at?
 
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THEFERMANATOR said:
Look at the pistom dome, that engine LEANED OUT BAD! theres not even a trace of black carbon or soot on it. A looper should always have some sort of soot on the piston dome when they are jetted to live, and there should be some traces of wetness.

Looking at your pics it looks like a small bore engine which were ALWAYS prone to overheating due to there design. Where are you located at?
Click to expand...

what he said
 
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