1977 200 hp johnson engine cuts out at 3000 +

[joemako]

Engine runs fine below 3000 rpm
above 3000 it runs for a few seconds and cuts out down to 1500 and a few seconds later its back to 2900, this goes on and on without moving the throttle from the 3000 position.
Tried to pump bulb when the engine starts to cut out but will not pump?
I drained the water filter and the bulb pumps hard.
It seems I have a air leak somewhere?

 

[emdsapmgr]

Re: 1977 200 hp johnson engine cuts out at 3000 +

Possible that you are losing spark. Check for spark on all 6 plugwires with an inductive timing light. That engine has two identical power packs, one controlling the spark on each head. If you find problems with spark on one head, swap the power packs and see if the problem moves to the other head.