My engine has started to get this hesitation sometimes when I'm pulling someone up (almost shuts off). It also at times shuts off when idling back to pick up a rider. No trouble starting and usually OK when accelerating slowly. I have the Mercruiser 350. Anyone had this problem? Fuel filter, fuel pump, sensor?

Fuel filter is cheap. <BR>Sounds like the filter or water seperator.

Mine has done it since new. We changed out a bunch of things to try and track it down but no dice. With 600hrs on the motor now it still does it once a day but has never let us down.

Check the distributor cap and rotor. I had the same thing on my Merc a couple years ago. Merc uses a vented cap and moisture causes corrosion. I changed fuel filters and drained the gas tank because everyone said it was bad gas before I went the spark route.

is it a carb motor? if so id check your accelerator pump

We had what sounds like the same exact problem. It was the fuel filter in our case (that as after new plugs, cleaning the gas tank, etc)

Ours did that too, sounds like pre detonation in our case, does it pop and surge? It will pull strong and then suddenly have a mare for a while, then come right. We haven't had the boat running (on the water, cranked it on the trailer a few times, don't want to go riding with no alternator) since the end of last season so we haven't had a chance to diagnose or fix it. The rotor cap was a bit corroded when we pulled that off, filled it with CRC and that seemed to help. Our alternator was toast too, so maybe it's not getting enough power. <BR> <BR>Is it a carbie or an EFI motor? One other thing we found was when the motor would shut off at idle we had a vacuum hose off the carb. Stuck it back on and she was mint. If that doesn't work maybe try bumping your idle up a bit. <BR> <BR>(Message edited by jtnz on August 10, 2008)