1980 Mercury 140 hp Inline 6... Timing Issues?

[Oldmanskier]

I am having a problem with my mercury 140. It starts fine and runs at high rpms fine . After it gets warmed up it seems to flood/choke out when you add in power even slowly. Hard to get it to plane. If you get it up thru medium rpms it will plane out and runs fined. Had carbs rebuilt, new plugs . Seems to me that it could be a timing or distributor adjust. No one in my area works on these older motors as the motor is older than most of the mechanic, any help or advise would be very helpful.

 

[Chris1956]

If you have a distributor, that motor is early 1979 or older. If you had the carbs rebuilt by a mechanic younger that 60 (sorry guys), he may not know how to set the idle mixtures properly.

If the motor stumbles when warm and you try to accelerate, it likely has too lean an idle mixture. If you know how to check the timing, you should have idle pickup timing of 4-6* BTDC and max spark advance of 21*BTDC.

Post back.

 

[Oldmanskier]

Thanks for the advice. The motor is a 1979 so I misspoke earlier. The boat is a 1980. I agree with your assessment of timing and carb adjustments. Wish there were more guys out there that still worked on these as it can be a costly adventure with those that don't understand these engine and can't just plug it in to a tester. I will give this a try and once again thanks for your hard numbers and time.