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Mercury 2001 125hp 2-stroke acceleration issue

mnep2025

New member
Engine idles fine but will kill after accelerating. I have had it into a local shop where they replaced the plugs and ignition stator with no change. They wanted to rebuild the carbs next but I took it home to do myself. Prior to taking it in, I replaced the fuel pump with known good pump (no change). I just rebuilt all 4 carbs and no change. They were pretty clean and I noticed nothing alarming when cleaning them out.

Some other things that have been replaced are:
1. fuel line bulb
2. oil check valve (tested bad - was allowing fuel to flow back to oil reservoir)
3. had compression tested and all 4 cylinders tested good.
4. impeller

I dont see any leaks in the engine compartment but have noticed a small amount of fuel in the water around the exhaust.

Is it possible the engine is getting too much fuel? How do I check for this?
 
Accelerator (boost) pump diaphragm or throttle pick up gap( I think .020"-.030") for the pump. Look there. should jump to 4 cylinders around 1800 rpms. That diaphragm last I checked was NLA, I found the same diaphragm was used on 9.9 and 15 hp engines as a primer diaphragm and worked perfectly for that boost pump, been there did it. Texas Mark may know more about this.
 
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