steelbark
03-31-2008, 11:30 AM
I have a 2003 Mecrury 9.9 , 4 stroke. I have a water separator on my boat and just changed out the plugs. The problem I am having is I can not get the motor to idle down low enough to troll. If I get it too low it will die. Any sugestions?
MattPark
03-31-2008, 03:19 PM
Sell it and buy something else.
-disgruntled Merc 9.9 owner
Actually, it sounds like your low speed jet may be clogged. Pull the carb apart and clean everything out.
I have a 2003 Mecrury 9.9 , 4 stroke. I have a water separator on my boat and just changed out the plugs. The problem I am having is I can not get the motor to idle down low enough to troll. If I get it too low it will die. Any sugestions?
As you look at the carb from the side, there will be a pencil eraser size brass plug at the upper left hand side, flush with the carb body. Very carefuly drill the center of plug out with a drill bit half the size of the plug. Just as the bit goes through the plug, it should "Grab" and the plug will pop out stuck on the drill bit. Now you can adjust the "Idle air Mixture" screw. When I did mine the drill bit hit the screw and screwed it in, so the starting point for the screw is 1 1/2-2 turns out if this happens. Now, run the thing in a tank in gear and you can adjust that Merc 9.9 to run just as good as a grey motor!!! Those 9.9s weren't really set up for super slow trolling (idling), they were set up for running faster....AND cleaner, to troll them down real slow the idle mixture needs to be a bit richer, so that's how you'll be adjusting the idle mixture screw richer (out/counter clockwise). Mine is an '01 and I had to do it in '03, I just re tweak the adjustment every year bofore I get on the water the firts time and it does good for the season.
SHhhhh, don't tell anyone but, A mechanic from a local high volume Mercury dealer, that may even advertise on this site will most likely give you the same advice, call them and see.
Smj