40 Merc engine issues...

[Hitman]

I have a 98 Tracker with a 40 Mercury on it. last friday went out to soddy and fished all day. I made several runs up the lake all the way up to almost Harrison Bay and back up past Possum Creek, the boat ran great. On my way back to the Soddy boat ramp at top end on full plane it just started dying. It acted like it was running out of gas but never would die completely just fall all the way to idle then rev back up and then die. it repeated this all the way to the ramp. Yesterday I went out again and it ran great on my way out to the lake, and I moved two more times with no trouble. then on my third move it started the same series of starting and stoping. Could this be a fuel filter or fuel pump or venting issue, or something electrical that gets hot and then starts shutting down. Any help will be GREATLY appareicated. Got to get this fixed, cant catch fish in the driveway!!!

 

[sduck]

I had that exact same problem with my OMC 50 SPL. It ended up being bad gas (water in the fuel/fuel line).

 

[Hitman]

It acts like a fuel issue to me also. I can drain the fuel and start over. Any additive I should use to assist clean out

 

[Fixxxer93]

Berryman B-12 seems to be recommended here. The other is Seafoam but its according to what you want to pay cause both seem to do a good job.
I went with B-12 cause it helps with water in fuel, plus gives it a good cleaning.

 

[Hitman]

Thank you guys. Gonna drain it and start over..

 

[TOMMY 20RXD]

CHECK AND SEE IF THE GAS CAP IS VENTED?

 

[Hitman]

I will look and see. Its the factory cap as far as I know.

 

[Fisherman550]

Had the same problem with a 2000 Johnson 70 HP. Drained fuel, cleaned tank, same trouble. In the shop several times, never did find the trouble. Finally ended up getting a new motor. I know this doesn't help solve your trouble though-sorry.