Rough running 4.3

[zach103]

I have a 2006 4.3 Mercruiser with the two barrel carb. I ran it a few times this season with no problem. Trip before last ran great then stopped it to hang out for a while, restarted it and it was running rough - at idle and under load. At this point we had about a 1/4 of a tank left. Next trip out we fill with new gas and add Startron to help, no change. Today I changed the fuel/water separator and all the spark plugs. It started up and ran smooth at the dock. Untied all the lines kicked into gear and instantly started rough again.

Are there any small in-line fuel filters that I'm missing?

Should I pull the carbs and try and clean them?

 

[alldodge]

You might have a TKS carb, don't know but a serial number would help.

If it is a TKS carb does it appear to run fine when cold but shortly after warming up it starts (doesn't take long)?

And there usually is a filter or screen at the carb behind the fuel line

 

[zach103]

This last trip it ran smooth for a few minutes after replacing the spark plugs and separator. After running for about 5 minutes at idle it went to running rough. The trip before it ran somewhat smooth - shut it down to fuel up. Once we started back up it was running rough.

 

[alldodge]

Need to know what you have

Suggest starting with dumping the fuel filter contents into a clear container (baggie) and see what is there. If anything other then clean gas there could be an issue. Check the filter in the carb. Check your fuel pressure and see if its between 3 to 7 psi

If nothing else shows something, and from what limited knowledge I have of how your motor is configured, I would look into a carb rebuild.

 

[zach103]

From what i read on some other threads i believe i have the TKS carb since all i do is turn the key to start. I will check the fuel and the filter before the carb. If that doesn't change anything i will check that the TKS is working right and rebuild the carb.