5.0L GM Surging at cruise

[ufm82]

Boat was running fine Saturday until I was headed back to the ramp- it started surging BAD. Up and down, up and down. Lost 700 RPM on top end but it idled fine. Take off was still good but anywhere 2000-4000 RPM, it would surge really bad. Even at WOT, it didn't have the power it did. Any ideas?<br /><br />1990 5.0L Mercruiser- GM power, carbed.<br /><br />Fuel/Water separator was clear, half tank of fresh fuel, running smoothly as in no missing, but surging badly. <br /><br />UFM82

 

[stormin4]

Re: 5.0L GM Surging at cruise

Had a similar problem with my 4.3 OMC. Check your alternator to make sure it is working. Also, check to make sure none of your spark plug wires are loose.

 

[gpane]

Re: 5.0L GM Surging at cruise

hi, thanks for replies<br />Things done: alternator belt was little loose, tightened to specs; changed thermostat; put fuel cleaner in tank; took of top of carb(edelbrock 1409 installed new last season) and adjusted float drop was 1/2 in to low and srayed with carb cleaner.<br />took the boat out next day ( fuel cleaner recommened letting sit for 24hrs- starbrite product)it ran great for the day then today problems started again: went out and after 10 minutes started to bog down and surge...got towed in and in dock i drained water seperator and gas had tiny dirt specs and some gell like substance forming on bottom( small little globs), i also removed paper fuel filter from canister and tore it open but it was clean...any ideas???? also after drained fuel was sitting in container for 15-20 min it became very cloudy wasn't clear anymore; in fact couldn't see bottom of container anymore...is that normal?

 

[gpane]

Re: 5.0L GM Surging at cruise

sorry wrong post read omc bogging and surging

 

[Bondo]

Re: 5.0L GM Surging at cruise

gas had tiny dirt specs and some gell like substance forming on bottom( small little globs),

That's Dirt,+ Water..........<br />That's Also the Cause of Your Problems .......<br />

also after drained fuel was sitting in container for 15-20 min it became very cloudy wasn't clear anymore; in fact couldn't see bottom of container anymore...is that normal?

No......<br />I Suspect it's got Something to do with the Fuel Cleaner you added.......