I have a 90s model 40hp 4 cylinder 2 Stroke Mercury that I am trying to figure out the issues I am having. I found a repair someone made, just under the bottom carburetor a piece about the size of a dime had broken off the power head block, they had used some sort of epoxy, it came loose and was leaking from the hole. I repaired the hole, the broken piece was still there, now it water and air tight.
Now I am having issue with a high idle, if I try to idle down lower than 1200 RPM it will die (in neutral out of the water). While it is idling I will get a puff/popping noise that seems to exit about the flywheel area, it will do it here and there, not constant. It was not doing this at all when the hole on the power head was open.
I pulled both carbs, checked the float levels, and making sure everything was right, according to the manual, the float level are spot on, parts are less than 6 months old, look wonderful.
I rebuilt the fuel pump, pumps great, fuel line and bulb holds prime great.
Plugs are great, the oil injection was removed, mix 50/1, plugs look perfect, plug wires off coils look great, fit tight.
I adjusted the air mixture on the carbs, it would still pop here and there no matter the mixture.
I took it out for a test run, ran great, but started to act up when I got back to the landing, as soon as I put it in neutral, it died, and was very hard to get to crank again, raised the fast idle, soon as I lowered it and put into forward, died again. Checked the fuel tank, not vapor locked, priming bulb firm and plenty of fuel in filter.
The outboard has been doing this for quit some time, so this issue did not just start.
What can I try next? Fuel? Spark? Both?
Now I am having issue with a high idle, if I try to idle down lower than 1200 RPM it will die (in neutral out of the water). While it is idling I will get a puff/popping noise that seems to exit about the flywheel area, it will do it here and there, not constant. It was not doing this at all when the hole on the power head was open.
I pulled both carbs, checked the float levels, and making sure everything was right, according to the manual, the float level are spot on, parts are less than 6 months old, look wonderful.
I rebuilt the fuel pump, pumps great, fuel line and bulb holds prime great.
Plugs are great, the oil injection was removed, mix 50/1, plugs look perfect, plug wires off coils look great, fit tight.
I adjusted the air mixture on the carbs, it would still pop here and there no matter the mixture.
I took it out for a test run, ran great, but started to act up when I got back to the landing, as soon as I put it in neutral, it died, and was very hard to get to crank again, raised the fast idle, soon as I lowered it and put into forward, died again. Checked the fuel tank, not vapor locked, priming bulb firm and plenty of fuel in filter.
The outboard has been doing this for quit some time, so this issue did not just start.
What can I try next? Fuel? Spark? Both?