Mercruiser 3.0L having trouble starting and idleing

[TarheelBoater]

I purchased my boat about month ago, it has a Mercruiser 3.0L engine. The first time i took the boat out after i purchased it ran and started great. Probably turned the engine off and started back up atleast 10 times that day. The next time i took the boat out about a week later it started up fine at the ramp then run down the lake turn off the boat to wakeboard and it wont start, we had to be towed back. I replaced the distributer cap and sparkplugs and it would start while on the trailer. I took the boat out again about a week after the new cap and plugs, it didnt start great but did start without much problem. Then had to sit under a bridge for about 20 minutes while a storm passed over and it was a little harder to start this time. After getting started i ran the boat for about 30-45 minutes without killing the engine. I turned the engine off to take a break and it fired up without a problem, ran for about another 30 minutes. When i go to start i took probably 10 miintues to start this time. The engine isnt idleing well either, i need to adjust the jet on the carb and unlock the screw, so thats a simple fix.

The first day out i let a buddy of mine drive the boat back to the ramp and he hit a small stick in the water, it made the motor do some funny stuff. After he hit it we turned the motor off and it took a while to shut off, it just kind of "sputtered" for a minute then turned off. Would this have anything to do with it? I also noticed that the lower exaust boot needs to be replaced. Could this be a problem?

Does anyone have any idea or solution to my problem? Please help.

Sorry for the novel just trying to explain my situation to get the best solution.

 

[tschmidty]

Re: Mercruiser 3.0L having trouble starting and idleing

Not sure what hitting a small stick may have done, shouldn't really have affected the motor. But it couldn't have been too small if you noticed it!

You have fuel problems. How old is the gas in it? Does it have a fuel/water filter? I would run it down as long as you can safely, then refill and see if you have better luck.

The other thing is to have the carb rebuilt by a qualified mechanic. There are some online places you can send it but it would be better to have someone local do it that can actually test the boat in the water.

 

[IES99]

Re: Mercruiser 3.0L having trouble starting and idleing

My similar experiences over the last 23 years tells me one thing: FUEL. Old fuel, clogged filter, dirty carb or needs carb rebuild come to mind first. Best of luck.

 

[TarheelBoater]

Re: Mercruiser 3.0L having trouble starting and idleing

Thanks. If it were bad fuel wouldnt that affect how it runs? It runs fine its just starting and idleing thats a pain. I do need to check the fuel filter. I have a buddy that a certified marine mechanic, i need to get a carb kit and have it rebuilt. I did refill the tank the day all this junk started, sounds like a probable cause to me.