3.0 L merc 140 fuel problem

[thomasl]

Hello my father in law just bought a 1986 four winns. It has a 3.0 140hp motor.He brought it home today and tried to start it and it would only crank. He took the fuel line off and cranked it and no fuel was coming out. Can anyone help us? Do you have to prime a mechanical fuel pump. The boat was stored all winter and the marina drained the fuel so he just put some in today and we dont know a whole bunch about boats.
thanks Tom

 

[Bt Doctur]

Re: 3.0 L merc 140 fuel problem

The best place to start is the Adults Section to download the manual for your engine and drive

 

[sea wolf]

Re: 3.0 L merc 140 fuel problem

Pump the dickens out of it until u see fuel shoot into the carb bowl. If that doesn't work u can coax it along with a little fuel poured into the carb. But, don't overdo it. And put the flame arrestor back on in case it backfires. Make sure the batt. is fully charged. Good luck.

 

[1216bandit]

Re: 3.0 L merc 140 fuel problem

Try starting the engine from an aux tank. If it starts/pumps fuel then you know its a problem with fuel delivery from the main tank and at that point I would check the anti siphon valve, that is the fitting your fuel line hooks to at the tank. I had the same problem with my 3.0 and this was the fix.

 

[sea wolf]

Re: 3.0 L merc 140 fuel problem

Check the anti siphon valve, that is the fitting the fuel line connects to at the tank.

Don't bother. There probably isn't one. The boat has been sitting all winter. Assuming that it's tuned up, the carb just needs a little coaxing. I run into this every spring with my 3.0. Mine has been sitting since last fall. I may fire it up today & will probably have to prime the carb.

 

[ken_23434]

Re: 3.0 L merc 140 fuel problem

Mine has taken a while to get fuel when I have drained the fuel tank also. I think it just takes a little while for the mechanical pump to draw a suction and get it to the carb.

PS

Make sure you have muffs on the drive supply water to it. Frequent newbie mistake.

 

[farmer9009]

Re: 3.0 L merc 140 fuel problem

Check the rubber seal around the fuel filter bowl that is attached to the fuel pump. (you most likely have this style fuel pump, the bowl may be on the top or bottom of the fuel pump) Mine was old and not making a good seal so it was sucking air instead of fuel. A new seal and filter from Napa fixed the problem.

 

[middle_road]

Re: 3.0 L merc 140 fuel problem

Could be the anti-siphon 'device' mentioned earlier.
On our '85 Thompson the check valve was stuck/corroded/messed up. No fuel was able to get through at all.
Was a real cheesy design for the environment that it has to operate in.

_mr