850 Merc 2 Stroke Carb Linkage Binding

Bawgger

Recruit
Joined
May 6, 2010
Messages
1
Just got a 1970's 850 Mercury 2 stroke outboard running after years of sitting, the only thing I did to it was clean out the mouse nests, added fresh gas, squeezed the bulb and she fired right up. Problem is, she wont hit full throttle. The top carb butterflies seem to be extremely hard to open and close, they don't follow the cams like they should and I can't even move them easily with a screwdriver by pushing on the top arm, these should open and close freely, is there an internal linkage that may be binding up or something. I'm not a 2 stroke guy or an outboard guy, diesels are my fortay. Previous owner said ran fine, just fell flat when you hit the throttle, go figure! Any ideas?
 

cr2k

Captain
Joined
Mar 19, 2009
Messages
3,730
Re: 850 Merc 2 Stroke Carb Linkage Binding

The shaft is probably corroded in the carb body. Try some PB Blaster and work it a little. If this fails you may need to pull the carb and do major cleaning.

Be very careful with the little cam follower, they get brittle.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: 850 Merc 2 Stroke Carb Linkage Binding

The throttle disks are attached to the throttle rods with screws. You may remove them and remove the throttle rods for a cleaning. Do not clean them too much, you want a snug fit.

I had my carbs throttle rods get real corroded. The corrosion was caused by the dry chemical of a fire extingusher. There is a valuable lesson here. if you spray ether into a cranking motor, that has spark, you will have a fire.
 
Top