Engine trouble....need advise

[Rtaylor343]

I have 07 310 Sea Ray with 5.0 Mercruiser 3 and stern drive. Boat sat for a year. Started it up with no problems. Used fuel treatment, changed fuel filters, impellers, oil and filters, and did general maintenance. Took it out on the lake and 20 minutes into the trip the port motor died. No alarms or warnings. Temp, oil pressure, water pressure, and motor was all good. Starts and runs about 10 minutes later. Runs fine and dies again. Then I couldn't start it again. Let the boat sit for a week waiting on a tech. Try to start the motor, and it runs great all day. Docked the boat for a day. Come back and the motor won't start. Cranks fine but acts like I am out of fuel, but have over 70% . Does anyone have an idea? I checked for water in the fuel, but did not see any. However, I couldn't get to the bottom of the tank because of some sort of fuel cage in the tank. Any help is greatly appreciated.

 

[Lazy Daze]

Try changing the fuel/water separater again.

Do you have one or two tanks?

Did you store the boat with fuel additive (ethanol?) already in it?

How full was the tank when you stored it? And, was the engine "put away" properly?

 

[gregkjones]

I had a problem similar in a 7.4L merc. It turned out to be the fuel pump. It worked for awhile (about 20 minutes like yours) and would die then work and then die and not start again for around a half hour. My mechanic told me that any water in the fuel that sits in the fuel pump all winter can damage it and you typically see these failures at the beginning of the next boating season. There is a fuel pump relay you should try to replace before the pump though because apparently they fail alot too but are only $25 so taking it out of the equation first is a good idea. Fuel pumps are waaaaaaaaay too expensive to replace unless you are 100% sure it is the problem (assuming it is a fuel pump for fuel injection). In my case it was and I have had no problems since.

 

[Rtaylor343]

Thanks for the info. I talked to a few techs and they seem to think the same thing

 

[l-skynyrd]

Had similar problems with my boat. Turned out to be the large cable
connector at the rear of the engine (part of which supplied power to the fuel pump).
Cleaned the connectors and have had no problems since. Try starting engine, if it does not start
turn key to run position and listen to hear fuel pump. If you can not hear the fuel pump you are probibly
not getting juice to the pump. Hope this helps...

Len