mercruisere 4.3 fuel problems

[lea]

Hi Guys
I have a 1994 Bayliner 2252 with a 4.3 mercruser that runs great most of the time, BUT on Sunday I took it out and it ran perfect for the first 40 miles, then it stumbled and quit, I though it was out of fuel but.... I put fuel in and had trouble starting it. I checked water seperater, goob. I checked filter at carb (2 barrel ) good. Checked electric fuel pump good 9psi.
I got it started and ran it for 10 miles , but it was not running the way it should.
At wot it seems to be missing a little we bit, is there any way it could be in the thunderbolt LV or do they just stop when they are done?
Any suggestions or help would be greatly appreciated, any ideas?
Lea

 

[Don S]

Re: mercruisere 4.3 fuel problems

Are you sure the engine isn't flooding out? That fuel pump pressure is really high for a carbed engine. 4-7 is normal.

 

[lea]

Re: mercruisere 4.3 fuel problems

Don that does seem a bit high I"ll get a new gauge and redo pressure test

 

[lea]

Re: mercruisere 4.3 fuel problems

Don that does seem a bit high I"ll get a new gauge and redo pressure test

I checked the fuel pressue agian with a different gauge about 6lbs, checked seperator and filter agian and added a can of seafoam, then went for a 15 mile ride ran good,stopped at a friends for 3 hours and it started right up when I left and ran good for 10 miles then it just up and quit, but it started rite up, I figured I should head for home about a mile from home it qit agian and woudn"t start for a couple of minutes, it then started and I did make it home,but I noticed that when it stumbled it would loose about 1000 rpm for a split second and return to whatever rpm I was cruising at, I am beginning to think that it is not a fuel problem but a electronic problem, is there anyway it could be a faulty tach, what kind of rpm should I be getting with this with a 17pitch prop? It will run right to 5000rpm