99 Mercury 2 cycle, 3 cylinder won't idle

Corrupt

Cadet
Joined
May 31, 2012
Messages
20
I friend of mine has a 3 cylinder Merc 75hp on the back of his pontoon that won't idle. He made the mistake of running it the first time this year without draining off the old gas. We have since cleaned out the carbs as best we could without removing them. I was able to remove the low speed idle adjustment screws and sprayed carb cleaner in there. Put the screws all the way back in and then backed them off 1 1/2 turns. We have ran about a gallon worth of gas mixed with seafoam through the carbs and she still will not idle. She will however idle if the choke is pressed and released a couple seconds before she dies. She runs fine when in gear at higher RPM's.

Will removing the top plate of the carb and cleaning that area help any? Also, all 3 carbs do not have the vent jet next to the low idle screws. I don't think these could be a problem as she ran fine last year without these in place. Can I spray carb cleaner into the vent jet holes?
 

Corrupt

Cadet
Joined
May 31, 2012
Messages
20
Re: 99 Mercury 2 cycle, 3 cylinder won't idle

Got it fixed. Pulled all carbs off...was a pita..and top carb idle jet was plugged, and the middle main jet was clogged a little. Cleaned all up and running. Now to put er in the water and fine tune.
 
Top