4.3 Merc with surging issues

[QUESTBLDR]

I bought a 1996 Bayliner with a 4.3 Merc. The engine idles fine, but when under load, it tends to surge part of the time, then run fine, then start surging again. I know the fuel is likely old, because the boat set for a while. Could it also be the spark plugs? Boat is in like new condition...really, and only has this issue. I don't know anything about the Merc's, so looking for a little assistance from the experts.

 

[Bondo]

Re: 4.3 Merc with surging issues

Ayuh,... I would be looking at the Fuel Delivery system,... Probably the Carb....
But,...
It's always a Good Idea to do a Tune Up if you don't know it's history...

 

[TBarCYa]

Re: 4.3 Merc with surging issues

I had the same problem with my 3.0L my first time out this season and when I pulled the plugs expecting to see that it was running lean (fuel delivery problem) I found that the insulator on one plug was damaged and I suspect that this is the cause. Due to the weather, I won't know for sure until next weekend if my problem is solved.

 

[QUESTBLDR]

Re: 4.3 Merc with surging issues

I have not attempted to change the plugs since they are such a bear to get to. That will be my first attempt to fix the problem. I do start the engine and run during the winter, so it doesn't sit for long periods. I would think if a carb problem, it would not run good part of the time. I'll take it in somewhere if I can't figure it out. Thanks

 

[180shabah]

Re: 4.3 Merc with surging issues

Sounds like it is time to catch up on some maintainin'...

Full tune up, and fuel system check.