90 Hp Johnson losing prime, stalls after 5-10 minutes at low idle

[Sinker]

If your trolling a lot with that engine, I would be adding seafoam to every tank, just to keep the fuel system clean. At trolling speeds, your burning more oil than you really need, so it tends to gum things up, and cause problems down the road. Seafoam really helps with carbon build up in two strokes. I swear by the stuff.

 

S.

[bare foot wader]

yep, I run seafoam in every tank, a full can if I'm filling the tank from almost empty...otherwise eyeball half or a quarter can accordingly

 

you could try a trolling plate or pulling a small drift sock (or bucket) to slow you down...but that affects your steering a bit, I've tried running a small sock under the bow, tied from the two front cleats, this seems to work better with steering control but you need to have it centered below the hull which can be tricky and if you're in a heavy chop your the bow will take a pounding

 

sinker explained it better than me....at slow speed there is too much oil added to the mix...my local shop explained it all to me, but I'm not mechanic smart enough to explain it back...lol

[DRIFTER_016]

If you add some Mercury Quickclean to your fuel it will take care of the carbon build up issue.

 

With my old 90hp 2 stroke I would have to hit neutral every once in a while and give the engine a rev with the high idle lever for a few seconds to clean out the plugs because they do load up and start to foul at trolling speeds.

 

I also kept a few spare spark plugs in the boat just in case I fouled the plugs.

[Entropy]

Hey guys. Boats been in and worked on with no luck thus far. Turned out the plugs were wrong and the mechanic felt I should reconnect the oil injection and run straight gas. He 'cleaned out the fuel system' whatever that means, but to no avail. It continued to stall when idling slowly. After waiting a few days with it in their possession with no work having been done, and no work to be done on it over the weekend, I decided to at least bring it home and have it in the garage over the weekend. So I decided to monkey around with it. I think I may have cracked the code. You guys let me know what you think. It's clearly (to me) that it is a vacuum issue. Fuel is being lost somewhere. I popped the cover off and happened to be pumping the bulb when I noticed gas dribbling/spraying out of the carburator. It could be that thus far, when I was looking at it the motor was fairly level, and not trimmed like I had it today, so I didn't notice this before. I don't think is is normal and my suspicion is that I have either faulty check valves or a float in the carburator that is stuck open. Does this seem likely?

 

Where did you take it for service?

[Doctrt]

 

Where did you take it for service?

I took it to Durham Marine in Ajax. Jury is still on their work until i run it this weekend, out but nice guys.

[canuckjack]

Comment from a guy who is definitely not a mechanic.

 

I had a similar issue with the priming bulb not staying firm with my 2 stroke 30 HP Johnson resulting in stall-outs and tough restarts. Replaced the line and bulb, same issue, replaced the molex connectors at both ends of the line and the problem went away. I assume there are o-rings in there that eventually wear out.

 

Just something to try if you didn't get new connectors when you did the fuel line change.