70Hp Triple Mercury Blueband

[gkm24]

Giving a friend a hand with his 70HP Blueband Merc 3 cylinder/2 Carb engine.
He says that it idles fine but then stalls as soon as he drops it into gear.
My first instinct is to check compression and then poss clean out carbs.
If that does not show up anything, I was going to make sure that the gearbox turns freely on the input shaft.

I am just posting this in the hope that someone may throw up a few more pointers. Not sure of the year but I will find out and post it up here.
Thanks for any help.

 

[guyjg]

He says that it idles fine but then stalls as soon as he drops it into gear.

May not be running on all 3 cylinders. Pull one plug wire at a time when at idle...use insulated plug pliers or equal. If there is no change that cylinder isn't working.

 

[gkm24]

Thanks very much for the reply.

 

[fastjeff]

Common problem with them. Here's what to do:

open the idle mixture screw 1/2 turn CCW. That will correct for the lean condition created by burning ethanol gas.

If that doesn't resolve the problem, get back to me.

Jeff