engine runs/stalls

[1980Galaxy]

I have a mercruiser 120 that im working on getting ready for the season. The engine starts right up no problem but after idling for maybe 30 seconds it starts to cough and sputter and then stalls out. any thoughts?

i was thinking maybe the fuel filter has water settled in it and when it starts up the water gets loose and clogs it up therefore choking the engine. the fuel filter was replaced last year. i have doubts about the quality of the fuel in the tank but i dont think its too bad.

any ideas on what to check would be greatly appreciated. and thanks alot for all the help you guys are giving me lately. i love what you guys have goin on here and your saving all of us alot of time and money. thanks again for the help.

 

[cooter2506]

Re: engine runs/stalls

Does this have an electric or mechanical fuel pump?

 

[havasuboatman]

Re: engine runs/stalls

If you think there may be water in the fuel, remove the watersaparating fuel filter and dump it into a clear container. If you see water, there you go. DO NOT REUSE THE FILTER. get a new one fill it with gas and install it.
When it's sputtering, is it back-firing thru the carb?
Bad gas is probably not your problem. If it will start with that gas, it should run with it.
Check the water separater, and run it again. If it is still dying, check for any other fuel filters that may be plugged. Then you will check your fuel delivery, is the fuel pump pumping? If it is, then, look at the carb.
Always check the simple stuff first.

 

[searay3]

Re: engine runs/stalls

Check and make sure the vent is clear, filters are clean and try running off a remote (outboard) tank with fresh clean fuel in it, plumbed in at the fuel pump intake. You can then eliminate the tank, anti siphon and fuel pickup...

 

[1980Galaxy]

Re: engine runs/stalls

fuel pump is mechanical and was just put in last season. ill check the fuel/water separator and see what turns up. where would i get a replacement fuel filter? there aren't any boat shops around here. would autozone have parts like that or would i hafta order online?

carb doesnt backfire when is sputtering... it just kinda slowly dies.

 

[Fishermark]

Re: engine runs/stalls

Check and make sure the vent is clear, filters are clean and try running off a remote (outboard) tank with fresh clean fuel in it, plumbed in at the fuel pump intake. You can then eliminate the tank, anti siphon and fuel pickup...

I second the idea of running it off a temporary tank for evaluating purposes. If it runs good with the portable tank, then you have a better idea where to look for problems. The same if it continues to run poorly - it simply narrows down the list of possible suspects.

fuel pump is mechanical and was just put in last season. ill check the fuel/water separator and see what turns up. where would i get a replacement fuel filter?

You can usually pick up fuel water separator filters at several places - NAPA carries them - maybe even Wal Mart. You mentioned in the quote above a replacement fuel filter. You ARE referring to the fuel / water separating canister, right? Not the normal fuel filter at the carb. The filter at the carb should be checked and / or replaced as well... but it is the water separator that is being referred to.

 

[1980Galaxy]

Re: engine runs/stalls

yeah, i was talkin about the canister... i replaced both last season but it would be a good idea to just change them both again. i dont get to take the boat out as much as i would like to so the gas sits in it and gets old.