Suggestions Please

[MYRX]

I have a 1999 OX225, (rebuilt 2.5 years ago) that has been performing well. Sunday as soon as it started it up it seem a little rough, normal initial smoking, then idled ok. I thought the motor lagged a little when I went to get on plane. Around 4200 rpm the motor skipped twice. This happened throughout the AM, so needless to say I didn't run as far as I had intended. Around noon the motor was skipping or missing more, especially over 5000 rom. I brought the boat in, (still idling ok) came home and pulled the plugs. All 6 were blacker than normal...almost looked fouled. Any suggestions where to look first?

I run one hotter grade plug than standard, I think 8's. I did add 10-12 gallons of gas 2 weeks ago on the way home from the lake, could it be bad gas. Also, yesterday, I thought I smelled gas twice. I intend to install new plugs this week. I am open to all suggestions. No real tune up was performed last year, just plugs and lower gear oil. The injectors were serviced when motor was rebuilt.

[Tromanoski]

I would run some sea foam in it before I took it to the shop.

[201pro]

Might check your low pressure pumps to see if they are leaking into the crankcase.

[MYRX]

I will check the low pressure pumps, but they were replaced last Spring as routine maintenance. I use ring free, should sea foam be added also?

[Bass Junkie]

You ever checked the O2 sensor?

[MYRX]

No I have not checked the O2 sensor. Sounds like I need a good service manual and learn how to perform a good tune-up myself.

[rat0502]

No I have not checked the O2 sensor. Sounds like I need a good service manual and learn how to perform a good tune-up myself.

Look at the "how to" sticky. Lots of maintenance info there, including removing and cleaning the o2 sensor. I tried to clean mine, but ended up replacing it. My symptoms did not match yours though. Certainly couldn't hurt to check it out if it hasn't been done in a while. I clean mine annually now.