1981 80HP Mercury Thunderbolt (S/N: 5773065) won't accelerate beyond 'Spark Stop' tab

[LtSteel]

Please help,
I have a 1981 80HP Mercury Thunderbolt outboard (S/N: 5773065).

It runs fine all day in neutral or in gear right up to the moment you accelerate the spark arm to the spark stop tab. I can run to this point all day long. The minute I try to advance beyond that point (thus advancing the throttle arm..???) the engine dies.

I have had the carbs cleaned and adjusted the "idle mixture screws" on the carbs (2) to run just perfect (I think). I just had the 'Power Pack' replaced and I am getting good compression and spark.
Do I need to adjust the 'maximum spark screw' or ??.

As a side note the idle adjustment screws/idle mixture screws (are they the same thing?) are just to the right (as you look at them) of the carb intakes, is this correct? or am I adjusting the wrong thing for the idle adjustment?

I am at a lose, it is only if I advance beyond the spark stop tab.

I can upload pictures if that helps.

 

[Chris1956]

OK, Ignition adjustments are: Throttle stop, Idle stop, Primary pickup adjustment screw. All are located on the throttle arm. Bottom screw is idle stop, middle screw is primary pickup adjustment and top screw is max spark advance. I would recommend you check the timing at throttle pickup and max spark advance.

The throttle cable must push the throttle closed against the stop when the throttle is in neutral.

 

[LtSteel]

Chris1956,
Thank you so much for the information. We are still trying to figure this out. it seems to run fine for a good part of the morning then as it warms up (the engine that is) it seems to not want to start or boggs down. The tech that worked on the power pack is going to meet us at the lake as we are not able to recreate the issue in the shop (with load on prop for full testing). I will update as I have more info.

 

[LtSteel]

Final update on this issue!!
Ok finally "got it working". it turns out that there is some skill to actually making a boat motor run and run well. things like how to start an older motor, actually shift forward enough o give the carbs fuel when transferring from idle to gear. we have not a problem since we learned how to run the thing hahahaha.