2002 F80 Rough Idle

My F80 has been running rough at idle since last year,I put it of until this spring to try and correct. The carb. that has the problem is the #4 at the bottom, my way of determining this was to pull spark plug wires until no change in run. I removed all 4 carbs. and cleaned float bowl,main jet,main nozzle and pilot jet along with the rest of carb. bodies. The #4 had the most noteable trash through out carb.

I still have the rough idle....next I checked spark...seems to be plenty there. Plugs on 1,2,3 cylinders are dry with a slight grayish color around tip. The #4 seems just to be there with not much of anything on it.

I ran the engine as is with the rough idle to see how it does under load at WOT in the water. Seems ok, runs up to about 5000 rpm,seems to have same speed on water as it had prior to the rough idle.

I checked the TPS seems to be at normal readings. Checked the electrolthermal valves they seem to be working also. I have a Seloc and a Clymer shop manuels for this engine.

Do you think I need a rebuild kit for the carb? Any suggestions would be great.

[boats.net]

The low speed circuit in carbs may still be plugged and may need to sync carbs.

The low speed circuit in carbs may still be plugged and may need to sync carbs.

Thanks boat.net for the reply...I was kind of wondering about the sync. Where would I find the low speed circut? Should I take the Pilot screw out to check and clean? That is the only thing I did not remove and clean.

Thanks
Firemans15

[boats.net]

The idle circuit would be the low speed jets and passages, you would have take carb apart to clean.