Mercury optimax sputter

[jtef270]

Hi I have a 2005 optimax 225, plugs, filter, fuel line has been done. At first start up in the morning it sputters and runs a tad rough. After that it runs a idles normal. My question is changeing the sparkplug gap a possiblity? I've seen on here that some of the pro xs motors have benefitted from this. Just curious. Also my friend has a 2006 optimax 225 and he has similar issues, I'm wondering if its ethanol related. Thanks

[EuropeanAM]

By any chance do you and your friend BOTH purchase the same fuel, from the same station or line of stations?

Before going to plug regapping (which SHOULDN'T be necessary on this engine, or the 2006), I'd recommend that you try a tankful of MID GRADE (89 octane) fuel from a DIFFERENT (well known brand, high traffic) station. Could be as simple as degraded or heavily ethanol-laden fuel.

[jtef270]

Don, I'll try putting fresh fuel from a different source in it. I didn't think re-gapping the plugs was the right thing to do, but you never know intill you ask Thanks

[F150owner]

My engine ran rough when I'd put it in gear and barely give it gas. I thought the plugs were fouled or I had a coil going. Based on Don's advice (from his posts on BBC), I filled the boat up with 89 at an ethanol free gas station. The difference is amazing. The engine acts like a new motor. Don't rule out crappy cheap ripoff gas. Additives only help with carbon buildup and keeping the motor clean but they can't help the gas become better gas.