Hi all-
Thanks for all the great info you have provided me over the past couple months. This will be my first official post, I guess, so go easy on me. Yes, I know how to use the search feature too, but looking for some specific advice here...
We recently acquired a second-hand 40hp 3cyl merc outboard. Its a 2000 model, sn: 0G992967, 40ELPTO. The thing runs spectacular above idle, but really puts up a fuss when dropped to slow idle/troll speeds. It starts without a lot of difficulty, but idles ok for 15-30 seconds and then "coughs" repeatedly. It acts as though it is one cylinder in particular causing the cough, and when it happens, it actually pulls the bulb soft ( not flat, but I was holding the bulb to see if I could prevent it from happening- just goes soft upon the cough, then back to semi-hard when running correctly). It doesn't die, but sure won't troll at no wake speeds for more than 30 seconds...
I just got a manual last night for it, so I will do the link/sync once I get my grubs on a timing light. The carbs do look positively spotless, and the floats seem to work smoothly. The reed valves are like new. FYI- the top cylinder seems to have a very rich piston wash- almost 1/2 the piston crown is washed clean (We used to read our snowmobile pistons with the wash trick... not sure if that applies here.
I will be replacing the fuel filter, but I'm at a bit of a loss as to where to go from here. I'm fairly mechanically inclined (former tool and die maker), so fire away! I would like to get back on the water!
Thanks for your time!
chico in MN
Thanks for all the great info you have provided me over the past couple months. This will be my first official post, I guess, so go easy on me. Yes, I know how to use the search feature too, but looking for some specific advice here...
We recently acquired a second-hand 40hp 3cyl merc outboard. Its a 2000 model, sn: 0G992967, 40ELPTO. The thing runs spectacular above idle, but really puts up a fuss when dropped to slow idle/troll speeds. It starts without a lot of difficulty, but idles ok for 15-30 seconds and then "coughs" repeatedly. It acts as though it is one cylinder in particular causing the cough, and when it happens, it actually pulls the bulb soft ( not flat, but I was holding the bulb to see if I could prevent it from happening- just goes soft upon the cough, then back to semi-hard when running correctly). It doesn't die, but sure won't troll at no wake speeds for more than 30 seconds...
I just got a manual last night for it, so I will do the link/sync once I get my grubs on a timing light. The carbs do look positively spotless, and the floats seem to work smoothly. The reed valves are like new. FYI- the top cylinder seems to have a very rich piston wash- almost 1/2 the piston crown is washed clean (We used to read our snowmobile pistons with the wash trick... not sure if that applies here.
I will be replacing the fuel filter, but I'm at a bit of a loss as to where to go from here. I'm fairly mechanically inclined (former tool and die maker), so fire away! I would like to get back on the water!
Thanks for your time!
chico in MN