1990 120hp L-Drive C model

[fireboater]

I have a 1990 21 foot Maxum with a 120hp L-Drive. Motor has low hours on a professional rebuild. It ran fine all weekend and then it stalled at a low speed. Had a little trouble getting it to start again but now it runs fine at an idle and up to about a quarter throttle. after that it has no pwer from mid to full throttle and falls on its face. What could it be. Carbs not in sync? Gummed up? Or ignition? What? Help!!!

 

[pnwboat]

Re: 1990 120hp L-Drive C model

Could be ignition or a fuel problem. If it starts up OK but and idles good, I would lean towards a fuel problem. Try squeezing the primer bulb as you accelerate to see if that helps. If it does, then I would suspect a fuel pump problem. Either the fuel pump diaphragm and or check valves.

 

[fishin1789]

Re: 1990 120hp L-Drive C model

I've got a 1992 120hp L-drive that HAD some of the same symtoms. It was a fuel problem. Start at the tank and check for any leaks, loose clamps, etc. After eliminating the fuel system all the way thru the carbs, check the electronics next. If you have fuel and spark, it should run. Timing can also cause this type of problem. FIrst thing that I did was to get a Clymers manual on the thing, I wear mine out, but it is starting to become a very dependable unit. Good luck!