omc engine surges

[gpane]

have a 1985 21' galaxy with an omc 305 5.0l and stringer 800 outdrive. Boat was running fine but on sunday starting engine started to surge after about 15 min of running almost to the point where i had to chug along at @ 900rpm. I would shut the engine down wait about ten minutes, start it up and it ran fine for about 10 min then started to surge and bog down again. Had to keep shutting down and waiting ten minutes, off and on in order to get boat back to dock. Temp. gauge read ok,(slight smoke from exhaust when problem occurres).

 

[cobra 3.0]

Re: omc engine surges

...sounds like it's not getting any fuel. It will surge when fuel is almost gone creating a lean condition and then stop.

 

[Boatin Bob]

Re: omc engine surges

Gerry....as cobra 3.0 suggests it sounds like fuel. It may even be the vent for the fuel tank is plugged creating a vacumn, check to see if it's plugged with(critters) or has a sharp kink. Next time out if it does it see if you can loosen or remove the gas filler cap, if you hear a whoosh or the engine picks up suddenly then thats your problem.

 

[hoot]

Re: omc engine surges

check the basics, fuel and spark. could be ignition since you are getting 15 minutes of run time. coil (or module) could be heating up then cooling down. when problem occurs, look in carb as someone hits throttle, any gas squirting in from accel pump? pull a plug wire, hold close to plug, look for strong spark to jump across gap as someone turns key to start.

 

[gpane]

Re: omc engine surges

haven't been down to check boat but just wondering....just remembered that i installed a trim guage a few days before this problem occured; boat ran fine on outing prior to install but had problem on first outing after instal of guage.... could the guage wiring be causing a short and affecting the engine...i wired according to directions and sender was already on engine...

 

[rattana]

Re: omc engine surges

Yes it could, disconnect all the new wiring to isolate it and retry it.