Not getting up to max RPM's - Water in Fuel?

[enginesilo]

Curious what some possible things to check are with my motor not getting up to Max RPM's suddenly?

Boat ran fine the first handful of times out but the last 2 times it would only get up to about 3700-3800rpm's and felt sluggish. It usually runs in the 4400 RPM range. I have ther Mercruiser 3.0L engine.

I was planning on checking:
-Spark plug gap and wires
-Change spark plugs if they look like they need it
-Check fuel pump filter-Does the 3.0L have a fuel filter inside the fuel pump? (The small one that is attached to the engine, I do not have a separate fuel separator installed)
-I know the carb could be to blame, but I want to try to rule out other things first

I also heard another boat had water in the fuel from filling up at a marina where I also filled up a few days before. Now that I think of it I started seeing these symptoms after filling up.

Would water in the fuel cause it to run sluggish and not hit max rpm's? Seems to run fine at lower rpm's though.

I think I might siphon some gas from the very bottom of the tank to rule out if I had water pumped in with the fuel.

Any other tips appreciated

 

[Limited-Time]

Re: Not getting up to max RPM's - Water in Fuel?

This link should help.

 

[enginesilo]

Re: Not getting up to max RPM's - Water in Fuel?

This link should help.

Thanks for this! Going to go down the list on the easier things I already know how to do.

 

[enginesilo]

Re: Not getting up to max RPM's - Water in Fuel?

I siphoned some gas out and found a tiny tiny bit of gas at the bottom. Is having a little bit of water normal due to condensation and such?

 

[Another retired guy]

Re: Not getting up to max RPM's - Water in Fuel?

I siphoned some gas out and found a tiny tiny bit of *gas* at the bottom. Is having a little bit of water normal due to condensation and such?

I assume you mean water at the bottom
No, a tiny tiny amount won't matter. How old is the gas?

 

[enginesilo]

Re: Not getting up to max RPM's - Water in Fuel?

I assume you mean water at the bottom
No, a tiny tiny amount won't matter. How old is the gas?

Ha Ha, YES, I meant water at the bottom:facepalm:

I started out with about 1/2 tank from last season and I used till almost empty, then topped off with fresh gas. Only reason why I thought of water in the gas was because that other person had some issues.

I went out tonight and it ran at about 4000 RPM's. Other than not feeling as fast or getting up to the higher RPM's it ran well.

My exhaust bellow is unhooked on the engine side of the lower unit so the boat sounds louder than it used to, but I'm thinking the unhooked bellow is the reason behind that.

I may change the plugs and see if there is any change to start.