2000 yamaha c115 premix power loss

[jajohns]

Engine is running fine when i put it in the water, full power. Run it for a ways and feels like I lose 2 cylinders. No heating problems or fuel problems, engine does stay running just has no power,even after setting for hours fishing,still no change.
Take it out the next day and is fine starting out but loses power again. Have not run tests on it yet , but wanted to know if it sounds like coil or trigger (pulser) problems.

 

[rejesterd]

Yes, it could be failed ignition parts (coils, plug wires, or the plugs themselves) when they get hot. Simple spark test should confirm.

Check the fuel pump diaphragm for holes.

Make sure the fuel tank is venting and there are no obstructions in the fuel lines.

Check that the fuel filter isn't clogged or has water in it.