Mercruiser 300 dies on the water

petertay

Seaman Apprentice
Joined
Aug 23, 2012
Messages
48
Older boat and motor, but new to us, so we don't know the history. Bought it from a dealer, and here in Illinois it would be a fresh water boat.

Engine starts immediately and runs fine. We've had it on the water three times and each time it quit after an hour. We don't see any common cause or event in the three times. Rough water or smooth water, WOT and slower. Temp guage shows normal range. Each time we got towed as it would NOT restart, but the next day on muffs, it fires right up.

Hmm. Where do we look. I'm guessing fuel line, but would appeciate all replies as we are new to boating so have no experience. Thanks.
 

tpenfield

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Jul 18, 2011
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Re: Mercruiser 300 dies on the water

I would start by verifying that the vent for the fuel tank is clear and allowing air in/out.
 

Don S

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Aug 31, 2004
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62,321
Re: Mercruiser 300 dies on the water

When it dies, do you still have spark? Do you get fuel out of the accelerator pump holes in the carb if you pump the throttle?
 

petertay

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Joined
Aug 23, 2012
Messages
48
Re: Mercruiser 300 dies on the water

Thank you both for the reply. We'll check the gas line and tank vent here at home next we pull the boat out of the shed, but Don's questions won't get answered until we're in the water if the problem comes back.

This was just what I was hoping for: a few suggestions to get us started. Thank you!
 

nola mike

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Re: Mercruiser 300 dies on the water

You don't need the boat in the water to try don's suggestions...
 

petertay

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Joined
Aug 23, 2012
Messages
48
Re: Mercruiser 300 dies on the water

Turned out to be electrical. Kill switch wire was shorting. End of topic.
 
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