[CARL SWINDLE]

I have a FS18 with the mercruiser 3.0 (2007 model year ) when the boat is in idle it idles very very rough the boat had been sitting for two months before I purchased it. Please advise on how to correct this issue Also I have been filling ther boat with premium fuel and adding startron after every use

[WetWilly]

Hi Carl, have you done a tuneup on the motor (plugs, cap, rotor, etc..)? If not, I would start there and I would also check the choke on the carb to insure it works freely.

If you still have the rough idle then try readjusting the idle mixture screws to loosen any foreign material that may be stuck in the idle circuit.

Try these and let us know how it goes.

WetWilly

[jeffro788]

Definitely try the plugs first, and you might run some sea foam thru it to clean the carb out a little. Since it is an '07 the wires and cap probably are ok I would think, but this is kinda my first go around with marine engines as oppose to cars. It may also clear up just from running it, blow out the cob webs!