4.3 mercruiser fuel problems?

[et_johnson61]

I have a 1990 celebrity with the 4.3 mercruiser that i purchased this winter, and am having some problems getting it to run right consistently. I recently put new plugs, wires, rotor, and fresh gas with some seafoam. The other day when we had it out it ran fine for about 45 minutes, then after being shut off for awhile started and ran for about 5 minutes at full speed, then started to sound like it was not receiving enough fuel. After it died, I opened the cover to inspect the motor and there was smoke coming out of the carburetor through the spark arrestor with fuel sitting in the carb. After letting the boat sit for about 10 minutes and letting that fuel drain, the boat started after some cranking with the trottle wide open, then seemed to run fine at about 25-30 mph the rest of the time. What are the possibilities that could cause this? <br />Also, what is normal operating temp on this motor? I was running at about 140 at idle and 170 or so at wot.<br /><br />Thanks for any help and I appreciate it

 

[Gary H NC]

Re: 4.3 mercruiser fuel problems?

Does this engine have a fuel water separater filter? If it does remove the filter and replace it..Napa stocks them. Also it could be trash in the carbs float bowl.Smoke coming out of the carb sounds like its flooding itself out.<br />With engine warm remove the spark arrestor and see if the choke is open.170 is not that far off on temp.it probably has a 160 degree thermostat.

 

[Bondo]

Re: 4.3 mercruiser fuel problems?

Just What Carb are we talking about anyway,..???...<br /><br />2bbl., or 4bbl....???<br /><br />Mechanical or Electric Fuel Pump,..???...<br /><br />I Agree with Gary,.... But,... Dump the contents of your Fuel Filter into a Glass Jar so you can See what's in your fuel.......<br />Just for Diagnosis sake.........

 

[et_johnson61]

Re: 4.3 mercruiser fuel problems?

It does not have a water/fuel separator, and I replaced the filters in the fuel pump and carb. It is a 2 bbl and I took the carb apart and cleaned it the best that I could. It also has a mechanical fuel pump