1998 120 Force-Trolling

[reddirt]

I have a 20' center consaole with a 1998 Force 120 and fish the islands of Hawaii. The motor starts fine, runs perfect under normal conditions, it has a new water seperator, fuel filter, and plugs. When we troll at low rpms it will run great for about 2 hours then it will start to knock and run very rough. We will open it up for maybe 30 seconds and it will clean up for about another 1/2 hour and then start process again every 1/2 hour until we are done trolling. When we pull the lines in for the short run back to the harbor the motor runs great. Any ideas other than a newer technology motor.

*Is there maybe a fuel filter in the carb?

Mike

 

[roscoe]

Re: 1998 120 Force-Trolling

The sparkplugs are probably starting to foul from the extended trolling.

I would suggest using synthetic oil in the fuel.
And adding Seafoam or Mercury PowerTune to the fuel.

Also, have the fuel recirculation system checked, it may be plugging up.

Other than that, it may just be time to have to have the carbs cleaned/rebuilt, and adjusted.

 

[reddirt]

Re: 1998 120 Force-Trolling

Thanks for the info i will give it a go.
Mike

 

[reddirt]

Re: 1998 120 Force-Trolling

Any other ideas?