75 mercury 850 85hp

[boat138]

i have a 1975 mercury 85hp and it runs great in neutral but as soon as it goes in gear it runs for about 3 secs and dies out you guys got any ideas

 

[Chris1956]

Re: 75 mercury 850 85hp

Normally that is the sign of dirty carbs and/or too lean idle mixture. What is the idle RPM?

 

[boat138]

Re: 75 mercury 850 85hp

i just rebuild the carbs before i took it out should i set the mixture in gear or in neutral

 

[nhtrax]

Re: 75 mercury 850 85hp

help i can reply but how do i start a new thread!! Sorry for cutting in like this

 

[Chris1956]

Re: 75 mercury 850 85hp

Boat, Mixture must be set in water, preferrably in forward. Adjust until idle is nice and smooth. Now richen top carb 1/8 turn and try to accelerate. If acceleration is poor, richen lower carb 1/8 turn and repeat test. Repeat sequence, testing after each adjustment.

On that two carb system, you should not have too much trouble getting mixture lean enough to idle and rich enough to accelerate smoothly.

 

[boat138]

Re: 75 mercury 850 85hp

i have one more ? how do u set up the spark arm should that move or is that a fixed part and to a post just click on reply on the side of the page

 

[Chris1956]

Re: 75 mercury 850 85hp

That motor should have a distributor-based ignition. There is a link and synch procedure that must be followed exactly to time and synchronize the spark and carbs. See the sticky for the link and synch.

 

[Chris1956]

Re: 75 mercury 850 85hp

The distributor has a brass collar that will move to adjust it to open the carbs. This collar is about 1/2 way up the distributor casing.