1984 Mercury Outboard 75 HP 4 cyl Bizarre problem HELP

I have the above engine on my boat. I bought the engine and controls from someone who started it (idling) on a hose. We shook hands, I paid him and got shafted.

The problem is; The engine starts and idles fine. As soon as you put it in gear and give it the throttle, the engine revs a little bit higher than idle, stays running, but barely holds 5 mph, a little more throttle and then it craps out. If you put it in neutral, it will start back up. It sounds like it is starving for fuel, but you can see the jets misting fuel and the butterflies opening.

Here is what IS NOT the problem: The Timing, the carburetors, the fuel system, the ignition module. The carbs are clean and shooting gas and opening. The ignition module aka (switch box) is new. The fuel pump diaphram is new. If you open the throttle as far as the engine will still remain running and spray carb cleaner into one of the carbs, the engine stalls. This was an idea suggested from another forum.

Compression is good, all 4 plugs are new and have a hot spark.

Electric choke works and is not stuck. Tilt cutoff switch disconnected.

I give up.

JP

You might get better responces if you posted in the mercury forum.

thanks, I'm new.