2003 Honda 225hp Rough Idle

I'm new to the forum so I hope I get my question right. My 2003 BF 225hp has started to run rough and sounds bad at idle. Yet it accelerates normally but still sounds rough at all power settings up to 4400 rpms. I've checked the oil level and the sparks all. are good. Any suggestion ?

Well, there are so many possibilities it's hard to know where to start. The first thing I would do is to pull the fault codes off of the ECU. The procedure for doing this is very simple and has been posted many times on this forum, so you can search for it. It only takes a paper clip. Or you can send me an e-mail at [email protected] and I will send you the procedure and the list of what each fault code means.

One thing that your brief description suggests is that you may have a bad HO2 sensor, which will not throw and alarm. If you pull the fault codes and you get a code "1" then it's likely the HO2 sensor.

BTW, when is the last time you changed the plugs and are they NGK IZFR6F11?

Tks for the info.I have never replaced the plugs but i have inspected them including the gap. And all looks good. You mention pulling the fault codes off of the ECU. I am not familiar with this procedure so if you would email me the "how to" instruction it would be highly appreciated.

wildbilldog

I replied to your e-mail and sent the procedure and codes this morning. Please post what you found from pulling the codes.

An interesting observation - 4400 rpm is about the speed where the VTEC kicks in, which changes the valve timing for better high-end efficiency. The VTEC function is the only significant difference between the BF 200 and BF 225.

Plugs and coils tend the fail at higher rpm's so it looks like that is probably not your problem. However, consider installing new plugs if your have anywhere near 400 hours on them.`