Motor DOC ? about 93 merc idle problems

dan(or) · 12-05-2003, 02:03 PM

Hi! I have a 93 merc 3 cylinder, 50 hp tiller with TT. It runs great at WOT and just about anywhere above idle.
However, I troll a bunch and this motor keeps dying at idle. I have replaced the fuel line, squeeze bulb, fuel pump kit, and inline filter.

Any ideas on where to start? could it still be in the fuel system? or is the problem in the black box? how would one test to find out which way to go?

thanks

dan

[ 12-05-2003, 03:04 PM: Message edited by: dan(or) ]

1pump · 12-06-2003, 07:22 AM

Idle mixture?

Trout,myster · 12-06-2003, 08:15 AM

Dan- A few years ago I had a 1990 Merc 3-cyl, 90 hp that acted similiarly after I bought the boat. I hate taking my boat in to be worked on so I took it to the lake and nosed it into a dirt bank with the cowling off and set my idle with it in gear under load. Do both the mixture and the idle. The other thing I checked was the ignition timing. You need a dial guage to verify the timing pointer is correct and then just use a timing light to check your timing. Get a Clymer or similiar service manual from your boat shop and it should explain how to check the timing.

Once I did those two things, I could troll all day. Still loaded up a bit at times as those big 2-strokes just don't like to idle long periods.