97 60 hp Merc chugging

[LindellProStaf]

I cleaned my carbs and rebuilt my fuel pump and it made no difference. Runs good at slow but when I accelerate it chugs like it is not hitting on all cylinders. I slowly throttle up a few times and it gets past the chugging point and takes off fine, runs good at fast speed. When I run slow for a short time I have to go through the whole process again to get fast speeds. I have changed plugs too. I am wondering if it is coils? Also unrelated my buzzer sounds sometimes even when the motor isn't running and I just turn on the key. It may stay on for 5 minutes after motor starts and then quits. Can start at anytime and quit anytime. Very annoying. I would appreciate any advice. Thanks.

[20lbSloughShark]

I had a very similar problem with my Johnson 40 hp. It turned out to be carburetors. Mine is a 2 cylinder with 2 carbs. The first time I just took it apart and sprayed it with cleaner through everything like normal, with no change. I took it completely apart, jets and all, and soaked it in one of those paint cans of carb cleaner for over a day, and put it together. I noticed right away, gunk got in places that a can couldn't spray out. Letting it soak gets it 100% clean. It doesn't take much to clog a carb. Someone might know better than me, but if it runs at high speed, I doubt it is a coil. BTW, what did your old plugs look like? White, brown, or black?

[LindellProStaf]

I can't remember what color the plugs were. Changed at last of season last year. When I took the carbs apart I just sprayed with carb cleaner and ran a thin copper wire in the holes to make sure they were open. Maybe you are right and I didn't actually get them cleaned. I did not find any deposits or anything in them.

[20lbSloughShark]

I would definitely start by cleaning them really well. If it ran fine before, it doesn't really matter what the plugs looked like. BTW, here is the stuff I use to clean carbs. Make sure not to put any plastic parts in, it can melt them (why take the chance?). If there is a plastic part that wont come off on the outside, just hang the carb body with wire so the plastic is out of the liquid. There is a tray too to put jets and other loose parts in.

[LindellProStaf]

Thanks Slough I will try that. I am also going to replace my bulb and hose. It is only 3 years old but the hose is hard already.

[20lbSloughShark]

Did you ever fix the problem?

[LindellProStaf]

Hi, yes after I took the carbs off and cleaned them it still wasn't 100%. I probably should have let them soak it the right stuff overnight like you mentioned. Well my fuel hose was hard as a rock. I put a new hose and bulb on and that helped some too. It does work much better now. If it gets worse I will do the overnight soak. Thanks

[Borch]

Hi, yes after I took the carbs off and cleaned them it still wasn't 100%. I probably should have let them soak it the right stuff overnight like you mentioned. Well my fuel hose was hard as a rock. I put a new hose and bulb on and that helped some too. It does work much better now. If it gets worse I will do the overnight soak. Thanks

Carb parts do wear out over time so performance issues isn't always related to dirty carb. When I rebuilt mine last time they were as clean as a whistle. The new parts fixed the issue.