1976 6 horse Johnson

I just acquired a 1976 Johnson that after not being run for 6 years started first pull.

The thing is it would die at idle and run fair with more throttle. When I pulled the choke out at idle, it would run for a minute or two more before dieing. I was 100% sure I had a gummed up carb and was about to call it quits for the night when I decided to dink around with it a minute more. It was hard to start so I pumped the bulb, which was still quite hard and fired it up again.
When it went to die, I pumped the bulb and it stayed running at idle very well. If I pump the bulb it stays running just fine. The thing is, I tried two different hoses and the issue remains the same, the bulb is not rock hard but is very full and pretty solid to begin with, however if I don't give it that little squeeze, the motor will die within 30 seconds at idle. Is this a fuel pump issue or what??????? Help!!! Thanks much in advance.

Re: 1976 6 horse Johnson

It is probably a fuel pump issue, but to be sure, elevate the portable tank above the engine and see if gravity will keep the engine running.

Re: 1976 6 horse Johnson

You may want to read this too: http://forums.iboats.com/showthread.php?t=158086

Re: 1976 6 horse Johnson

Wow!!!
Thanks for the quick responses for the newbie here. I appreciated the link to "resurecting a motor" or whatever the title was as well. I've done most of what has been suggested short of the impellar. It pumps water fine, but I'm worried that if I don't replace it, its almost guarenteed that it will shred leaving chunks of rubber plugging off the cooling passages in the power head if I don't.

I didn't even think about running it with the tank above the motor. Thats a good test to look at.
I thought it would have at least sucked the bulb down more than it did however. When dealing with the Merc's I've owned they've always sucked the bulb down quite a bit when it was a weak fuel pump. This one had me stumped and didn't make a whole lot of sense. Thanks again!!!

Re: 1976 6 horse Johnson

Here's a new theory as I'm not sure its fuel pump issues now.....When I pump the bulb, its forcing gas past the garbage (old corroded dried up fuel) enought to run.
The reason I say this is that it will only run for about 30 seconds or less after I pump the bulb.
I guess tearing apart the carb isn't a big deal eitherway. The fuel pump for this model is about $80, actually almost what I paid for the motor.

Re: 1976 6 horse Johnson

If it runs at highish revs but not at idle it points to the carb needing a clean, at least the slow running jet.

If you can keep it running with a bit of choke it also points to the carb needing a clean.

If you can keep it running by pumping the bulb it points to the fuel pump or to air being sucked in somewhere. Check in particular the connection with the motor.

You have checked the obvious, namely the tank vent!