1973 merc 850 falls on its face when warmed up

[Jdevon_14]

I got a 1973 merc 850. Just did a link and sync on it to fix an idle issue I had. Now when I take it out on the water after it gets warmed up.it has an issue staying running. It idles fine but if you try to give it throttle too quickly it dies out. Was thinking could be the throttle opening up too soon but I'm not sure.

 

[Chris1956]

Mercs of that era need an extra rich idle mixture to allow for acceleration.

So set the idle mixture screws 1-1/2 turns open, and water test it. On the water, with a warm engine and fresh fuel mixture, try to accelerate. If she dies or "falls flat", open the top carb idle mixture screw 1/8 turn and try to accelerate again.

If she hesitates or worse, open the bottom carb idle mixture screw 1/8 turn. Repeat sequence, test acceleration after each adjustment. Find the best idle quality that allows smooth acceleration. it will be a compromise.

 

[Jdevon_14]

I'll give that a try