140 hp Johnson
 

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 will do

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.

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

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.