mercruiser 5.7 stalls after 20-25 min

[novice boater]

after running great for 20-25 minutes @ 3500 rpm, engine stalls, then will not run over 1600 rpm. cleaned distributor, replaced water separator filter, cleaned flame arrestor....have received lots of advice-water in gas is the most frequent advice. 90 gal tank had less than quarter tank, filled up- no help. added heet.<br />thanks in advance

 

[olbuddyjack]

Re: mercruiser 5.7 stalls after 20-25 min

novice boater, Welcome to iboats.<br />To quote the guy at the parts counter: "year, make and model."<br />Sounds like you covered the generic stuff.<br />Maybe that shoud be "year, make and hp"

 

[Laddies]

Re: mercruiser 5.7 stalls after 20-25 min

It sounds like a vacume problem at the fuel tank, have you ried to run it will the fuel cap loose? Some tanks have a screen on the pickup, a bad anti syphen valve at the tank or a plugged filter

 

[hoot]

Re: mercruiser 5.7 stalls after 20-25 min

look at ignition system. heat affects ignition components similar to what you describe. if regular ignition, replace coil, points, condensor, rotor button, dist cap,...if electronic, wait for other replies. and check gas tank vent. remove gas cap and see if boat runs ok. some vents can get clogged by wax, dirt, insects, etc

 

[vipzach]

Re: mercruiser 5.7 stalls after 20-25 min

I think "hoot" is on the right track, it sounds to me like a coil or something is getting hot.

 

[PeteHarris]

Re: mercruiser 5.7 stalls after 20-25 min

Similar problem -- Wouldn't restart after warm ... replaced coil and wires and problem went away ... upon further examination the do-hickey on the top of the coil that the wire connect to was in bad shape (sorry to use technical terms)<br /><br />HOSS

 

[craze1cars]

Re: mercruiser 5.7 stalls after 20-25 min

Sounds a little like vapor lock? If this machine has a mechanical fuel pump, the fuel might be boiling in the lines when the engine is hot and boiling gas is not pumpable. A short-term old-schooler test for this is to insulate metal fuel lines with aluminum foil and see if the problem disappears.