Ragged runner

[lwdisparte]

1997 Force 75 hp. Starts great, idles great runs great at speed. The problem is when accelerating it runs ragged as the rpms increase until it "clears its throat' then runs super.<br />It's like it was flooded and needs to clear out. I've had two shops look at the motor but it's hard to make it do it without it being in the water.<br />Any help would be appreciated and thanks in advance.

 

[roscoe]

Re: Ragged runner

Welcome pagorits.<br />What if anything have the shops or you done to the motor?<br /><br />Does this happen every time, even after you have been running full throttle for a while?<br />Does it happen after the motor has been sitting unused for a day or two?<br /><br />What happens if you hit the choke while trying to accellerate?<br /><br />Could be the fuel pump is leaking gas into the block and flooding it. Easy fix, a fuel pump diaphram kit is about $18 at a Mercury dealer.

 

[lwdisparte]

Re: Ragged runner

The shops have just done tune-ups, which basically consists of new plugs.<br />This is a fishing boat and this happens every time I start up and move. Even from the ramp first thing in the morn.<br />I just rebuilt the fuel pump but haven't had a chance to try it yet.<br />My next step will be too rebuild the carburetor. I thought it could be that the needle valve is leaking by and flooding it.

 

[lwdisparte]

Re: Ragged runner

Well, the fuel pump didn't change anything. Is it possible it's not fuel, maybe electrical?

 

[RRitt]

Re: Ragged runner

sounds like a lean idle speed mixture or timing advance problem to me.<br /><br />get a paper and pencil. you might not remember original settings by time you finish, so write it down. count how many 1/8th turns it takes to lightly but firmly seat the idle mixture screw. write this number down. check the manual for the default setting. Is it the same? It should be very close. Like within 1/4 turn. Usually within 1/8th turn. Generally speaking, if your idle mixture is lean then the engine will buck & sputter on acceleration. If it is rich, then the exhaust will make sputterring sounds on deceleration. Timing can do same but its hard to mess up acceleration timing without also messing up steady speed timing. So I'd check for a lean idle mixture.