2003 Honda 40's no power

RileyDog · Posted: Sat Sep 30, 2023 10:18 pm Post subject: 2003 Honda 40's no power

and think it's a fuel problem ...

The boat ran excellent a month ago, 4500 rpm approx 17knts all was well. I then took the boat out of the water and it sat on the trailer for 4-5 weeks. I didn't do any fuel draining from the carburetors or any other preventative maintenance. The fuel in the tank was regular gas from Petro Canada ie high in ethanol.

Today, we launched the boat, the engines started up fine but they wouldn't stay running ... and there was no power. We held the throttles at full throttle but they wouldn't come above 2000rpm.
We limped home and now have an issue.

Any suggestions on what direction to look and possible fix would be mucho appreciated.

jkidd · Posted: Sat Sep 30, 2023 10:53 pm Post subject:

I would start with fresh gas first

DayBreak · Posted: Sun Oct 01, 2023 1:13 am Post subject:

I definitely agree with Jody. My experience with ethanol and carburetor motors is that it will gum up the carbs eventually if the motor is not run often enough. The motor may run like normal on initial start-up but then run poorly after that.

You may also want to change out the fuel/water separator filter to see if that may be the culprit.

Keep us informed as to the outcome of your motor issue. Gary

T.R. Bauer · Posted: Sun Oct 01, 2023 1:39 am Post subject:

I just worked on a yamaha with the same issues. It would idle fine, but giving it some throttle and it would not make adequate power. The carbs were full of gunk and it took hours to get them cleaned up. Leaving gasoline in them allows the various metals to have a chemical reaction party. Ethanol likely makes it worse. If there's water? Yeah.....fun. However, with that said, once you clean them out, they will work again.