2005 Yamaha 4 stroke 30 hp jet outboard

[shadpuller]

This motor has been driving me insane. One time it will run 23 to 24 mph. Next time it won't run over 12 to 14 mph. Sometimes the speed fades as you go up the lake. I have replaced plugs, fuel filter, fuel line and bulb. I run only non ethanol fuel in it with a light dose of Sea Foam in every tank. Has anyone else experienced anything like this?

[drag4striper]

Just a thought. Make sure the vent to your fuel tank is all the way open or not obstructed.

[shadpuller]

That is a great thought. I did check that as well, but thank you for the thought. I am afraid it is going to require a trip to the shop.