mercruiser stalls under load

[jmccall001]

my mercruiser 260 started stalling when put under load. At idle in slip no problems, under load at 2000 rpm for about 30 min, it runs smooth as silk, then sputters, threatens to stall then stalls and will not start. Put it up past 2800 rpm, it begains to sputter and then stalls and will not run. I've replaced fuel filters, (both) the fuel pump- slightly weak, checked compression, timing and replaced the carb. The only other "symptom" is that fuel must be added very slowly to the tank from the pump. If y ou do not periodically stop, the fuel will bubble out of the filler.<br /><br />I need help

 

[rodbolt]

Re: mercruiser stalls under load

check the fuel vent. you may try a test run with the filler cap off. just dont lose it . but it sounds like the fuelbowlxis running out of gas. you can also try a remote outboard tank.<br /> you can asloinstall a vacum gage in the fuelline at the pump to test for fuel system vacum. if more than about 3"Hg then look for a restricted/pinched line, a restricted/stuck anti-siphon valve or a clogged fuel draw tube. seems some makes of tubes have a filter in them, have caused more grief than you can imagine.

 

[TilliamWe]

Re: mercruiser stalls under load

I am no mechanic, but I was going to suggest that you check the check valve at the top of the pickup tube in the tank. There can be a screen in there that gets clogged, or the check valve itself gets dirt in it.<br />You last two sentences also make me wonder if your fuel tank is venting properly. That might be a source of your trouble.<br />See what Bondo & DonS say.<br /><br />Or Rodbolt@

 

[beezee28]

Re: mercruiser stalls under load

if fuel is bubbling out of the filler when filling up with gas, it is a definite sign that the fuel vent is block. Check the for vent if it is clog. Sometime the 'mud bee' like to built their nest there. When I fill up with gas I have to fill her up slowly because the vent will spil out gas when filling her up too quick.

 

[waterone1@aol.com]

Re: mercruiser stalls under load

I have to agree with the other posts, sounds like a fuel restriction, most likely in the vent line, causing a vacume in the tank.

 

[2kflhr]

Re: mercruiser stalls under load

I had a problem with a 3.7 that would run like a top for about 30 mins. at WOT, then it would start to pop slightly and lose power. I changed the filters, points, coil, and etc. I ohmed out the wires and they appeared good. As a last ditch effort I replaced the wires and that cured the problem completely. Might not be oyur problem but it might be a lessons learned for someone else.

 

[Bondo]

Re: mercruiser stalls under load

The only other "symptom" is that fuel must be added very slowly to the tank from the pump. If y ou do not periodically stop, the fuel will bubble out of the filler.

Ayuh,......... No Doubt...... Everything rodbolt says...........<br />The Vent is My 1st Guess...... Could be somewhere else,.. But, I'd say it Is a Fuel Issue..........<br /><br />BTW,......Welcome to the iboats forums....

 

[hoot]

Re: mercruiser stalls under load

john, check out the ignition system also. since you are getting ~30 minutes of run time, that will let the coil heat up and it could be breaking down. electronic ig. will do the same.