mercruiser 3.0 running issue

[slredstorm62]

my freind has an 88 glastron with the mercruiser 3.0 I/O and after driving it on the lake for a while, around half hour or more the engine will start running like crap. it sounds almost like its flooding out. it will do this until you idle down the the engine shuts right off then wont start again. i pulled all the plugs when this happened and they were all dry. and suggestions???

 

[SeaRay182noob]

Re: mercruiser 3.0 running issue

Sounds fuel related to me. Maybe clogged fuel filter or weak fuel pump. My brother had a similar issue two weeks ago which ended up being a fuel filter. After driving for alittle bit it would bog down when tring to go but his didnt stall and would idle fine. Put a pressure gauge in it and see what happens. Ignition related issues usually happen suddenly and may jerk or studder. Not sure if this helps but its all i got Goodluck!

 

[Rocky_Road]

Re: mercruiser 3.0 running issue

I would check that the gas tank vent isn't clogged. If it is, you will run just fine...until the gas tank develops a vacuum.

Easy to eliminate as the potential problem...just 'crack' the cap, and see if your problem still happens!

 

[DD2]

Re: mercruiser 3.0 running issue

I have a similar problem. My 3.0 ran good for about an hour and then it started to miss just alittle. Kind of like to the tempo of rolling through the swell (just as the boat was coming down the back side of the swell/chop). Then it started to sputter choke and die. This has happened twice on the lake. The first time we ended up having to be towed in as it just would not start. The second time it would start and run for maybe 10 seconds or so before dying (just enough that we could limp it back to the boat ramp). After the first time I changed the plugs, fuel filter, coil, points, rotor and condenser.
This time I'm thinking fuel related. My plan is to replace the electric fuel pump with a mechanical. Also it does not have a water fuel seperator on it so I'm putting one of those on. I'm going to drain the tank (as I've heard that the ethanol that is being put in gas is causing this type of problem) and replace it with pure gasoline along with the additives Mercury Quickleen and Dri-Fuel. Any suggestions?
*The clogged tank vent creating a vacumm is an interesting theory!!

 

[slredstorm62]

Re: mercruiser 3.0 running issue

i had an old external gas tank that did that...it would run fine the all the sudden die and wouldnt start back up haha