Rough idle after running awhile

[3gsdad]

When I start the boat it idles fine and runs great. But when I come back to the ramp after a few hours of problem free running it stalls when I put it in nutral. I can get it to start again if I put it at 1/4 throttle but i have to get it back in gear quick. I have done some searches here and havent found a fix for this problem. I am thinking maybe a fuel filter, or somthing that has to do with heat????

Thanks in advance for any help ya'll can give.

 

[dubs283]

Re: Rough idle after running awhile

what ya got for an engine??

when was the last full tune-up?? is the coil getting hot??

have you inspected any fuel filter(s)/water separator??

 

[3gsdad]

Re: Rough idle after running awhile

Sorry I should have specified what engine.

It is a 2006 mercruiser 135 HP.

Some other clues; I just bought it and the previous owner said it sat for three months without being ran.

It had 1/2 a tank of gas I have no idea how old or if there was stay bil in it. I filled it up and am just now at a half a tank.
Would it be a good idea to run sea foam or some other fuel treatment through it when I fill it up again?

Where is the seperator and the fuel filter in the gas tank?

 

[dr1chert]

Re: Rough idle after running awhile

I have a 2007 glastron 185 gxl with 4.3 gl-g gas engine and have the same stalling problem. I will put the boat in the water and it will start and idle fine but after several hours it won't idle at all and I have to have it at quarter throttle just to keep it going. I am suspecting the ignition coil myself or the coil wire itself? Has anybody else figured this out yet? I am replacing the ignition coil today and I will post my results when I check it out.

 

[dubs283]

Re: Rough idle after running awhile

Where is the seperator and the fuel filter in the gas tank?

4 cyl mercs don't usually come with a water separator, if you had one it would be mounted in line with the fuel line and looks like an oil filter (spin on type)

there should be a filter on the fuel pump itself (STBD side of enine) again, in-line with the fuel line

there should also be a filter in the carb where the fuel line enters - you will need a 5/8" flare wrench and a 1" wrench to remove the fuel line from the carb