She dies after 20 minutes or so....

Hey folks,

I recently acquired a 15 Hp johnson (1981) and am having some issues with it. She starts up and runs like a top, then bogs down and dies. After she dies it is hard to restart, and sometimes starts and putters back out again, but after i let it sit for a while i can start it up and she will run like a top for another 15-20 mins then die again.

I have already:

changed fuel pump
new fuel and primer bulb
changed impeller (it needed it done)
brought it to the shop and had them mess around with it and they said she was ready for the water (200 dollars later and she is still not fixed); they said that the idel knob was broke so they fixed it, and changed lower unit oil and prop seal

I just did a compression check and got 110 on both cylinders... is this okay? I have never had an OB before, just in/out boards....so any help would be appreciated. I really dont want to take it back to the shop so i can throw more money at them for nothing.

Re: She dies after 20 minutes or so....

Hi mrdopes. Have you rebuilt the carb lately? I'd start with that then move on to spark, if that doesn't fix it. You should be able to get a carb kit right here at iboats. Sounds like the compression is good, so all the rest can be fixed.

Re: She dies after 20 minutes or so....

doubt it is the carb if it it runs that well for that long. I would think the coils are breaking down under heat. It's a common problem. Next time it dies on your check the spark before it cools off.

Re: She dies after 20 minutes or so....

it has spark when hot and cold, and as a recent development, it wont run more than a couple minutes now. It will start however if i shoot some pre-mix in the intake.... carb??

Re: She dies after 20 minutes or so....

when i prime the bulb, i noticed that fuel seeps from the connector (not the hose) where the line hooks to the motor....could it be that it is sucking in air there? i doubt it should be doing that...

Re: She dies after 20 minutes or so....

it could be sucking air. change the fuel line running from the tank to the motor and see. I still don't think it's the carb if it indeed ran that good and that long.

Re: She dies after 20 minutes or so....

Check your coils, if they are cracked or look burned, you might need to replace them. I had a set on a sea horse 5 hp that once they heated up they stopped working.