Hey guys, Got a 1999 Force 120. When running at anything above 4800 rpms, should I trim the engine up, after about 30 seconds running fine, it starts to slow down. Anything under 4200 rpms I can trim but over I get this issue. If I start trimming it back down the engine recovers and comes back to speed. I have a trim guage, I am not trimming it up alot, just to the first mark up. It would be at like 1/4 tank mark if it was a up/down fuel guage.
I just bought this boat, engine ran fine and I never trimmed it up. After 2 months I played with the trim and found this issue. Engine beine 10 years old is in excellent condidtion but things start wearing out as would be expected. Recently, had issues with a leaking carb, found the needles worn and the fuel line deteriorating. Pulled the bowls, sprayed the passage ways, replaced the needles. Found the fuel lines from the tank to the engine deteriorating internally so replaced it with a 12ft universal line and bulb. Cut off the excess and used it to replace the short line inside the engine cowl from the connector to the fuel pump, then used auto fuel line to replace from the fuel pump to the carbs. When I pulled the quick disconnects to use them with my new line I found them just packed full of the fuel line interior liner! Anyway, cleaned them all out, blowed air thru them etc and also cleaned out the fuel tanks. So basically all the fuel lines replaced, cleaned connectors and new needles. Didn't replace the fuel pump diaphram although I have one but replaced the fuel filter after it incase there was a bit of liner still in there. So, engine runs perfect as when I purchased the boat, idles perfect, needles seat so carb doesn't leak, runs at 5250 WOT but still baffeled why the engine doesn't want to run trimmed up at more than 3/4 throttle? Any Ideas?? Boat is a 24ft Pontoon rated for a 120hp.
I just bought this boat, engine ran fine and I never trimmed it up. After 2 months I played with the trim and found this issue. Engine beine 10 years old is in excellent condidtion but things start wearing out as would be expected. Recently, had issues with a leaking carb, found the needles worn and the fuel line deteriorating. Pulled the bowls, sprayed the passage ways, replaced the needles. Found the fuel lines from the tank to the engine deteriorating internally so replaced it with a 12ft universal line and bulb. Cut off the excess and used it to replace the short line inside the engine cowl from the connector to the fuel pump, then used auto fuel line to replace from the fuel pump to the carbs. When I pulled the quick disconnects to use them with my new line I found them just packed full of the fuel line interior liner! Anyway, cleaned them all out, blowed air thru them etc and also cleaned out the fuel tanks. So basically all the fuel lines replaced, cleaned connectors and new needles. Didn't replace the fuel pump diaphram although I have one but replaced the fuel filter after it incase there was a bit of liner still in there. So, engine runs perfect as when I purchased the boat, idles perfect, needles seat so carb doesn't leak, runs at 5250 WOT but still baffeled why the engine doesn't want to run trimmed up at more than 3/4 throttle? Any Ideas?? Boat is a 24ft Pontoon rated for a 120hp.
