97 yamaha 225 OX6 efi rough & high idle

[Seafarer]

1997 Yamaha 225 OX6 EFI w/oxygen sensor, idles unusually high and is rough running only at idle. The engine performs perfectly at all other ranges. If I full throttle it (in gear) for 30 seconds to a minute and come back to idle it is fine. I have replaced spark plugs twice and this has not changed anything. I have also clean the oxygen sensor and sleeve with no change. Some have told me the oxygen sensor can cause rough running at higher rpm's. My problem has been only at idle. Has anyone had this problem? Sure could use some help. Thanks in advance!

 

[Dhadley]

Re: 97 yamaha 225 OX6 efi rough & high idle

Im sure you mean an OX66. What are you running for a battery? Are you using wing nuts or nylock nuts?<br /><br />Good luck!

 

[Seafarer]

Re: 97 yamaha 225 OX6 efi rough & high idle

I have two group 24 Interstate marine batteries with a splitter. I am using the standard battery nut (stainless?). It's not a nylock. Whats your thinking? Oh yes! It's an OX66

 

[John from Madison CT]

Re: 97 yamaha 225 OX6 efi rough & high idle

Rich,<br /><br /> Go to:<br /><br /> http://www.boatsetup.com/cgi-bin/ubb/ultimatebb.cgi?ubb=forum&f=7 <br /><br />This is a great website for specific Yamaha OB help.<br /><br />Good Luck,<br /><br />John from Madison, CT

 

[Seafarer]

Re: 97 yamaha 225 OX6 efi rough & high idle

BIG Thanks John. I posted on the site you sent me and got immediate help.<br />Rich

 

[DJ]

Re: 97 yamaha 225 OX6 efi rough & high idle

Rich,<br /><br />What was the answer? Someone else, down the road, here may need to know.

 

[Seafarer]

Re: 97 yamaha 225 OX6 efi rough & high idle

It looks like the Oxygen sensor may be the culprit. After posting a notice on the recommended site. I searched and found numerous postings and similiar problems with the oxygen sensor. The proof however will be when the sensor is replaced and the problem resolved. I intend to update when I replace it.<br />Rich

 

[John from Madison CT]

Re: 97 yamaha 225 OX6 efi rough & high idle

Rich: I have a '97 Yamaha 250hp and I know for a FACT that there was a Service Bulletin that covered a new O2 Sensor pick-up tube.<br /><br />Although long out of warranty, you still should do it. I bet that takes care of things.<br /><br />John from Madison CT

 

[Seafarer]

Re: 97 yamaha 225 OX6 efi rough & high idle

Your correct on that John! Yamaha technical bulletins # 099-013 and 99-008. There is a change in the oxygen sensor draw tube. Mine is clearly the old style. <br />Thanks again,<br />RIch

 

[seahorse5]

Re: 97 yamaha 225 OX6 efi rough & high idle

For info on how the O2 sensor works and how to test it, go to:<br /><br /> http://www.thebassguide.com/home/News/05-30-2002-01.htm

 

[John from Madison CT]

Re: 97 yamaha 225 OX6 efi rough & high idle

Rich: Glad to be of some help to a fellow Yamaha owner.<br /><br /> Keep us a****** of how things go and don't forget that "other" website I have you for specific Yamaha Help.<br /><br />Take care,<br /><br />John

 

[John from Madison CT]

Re: 97 yamaha 225 OX6 efi rough & high idle

Geez, I meant to say "abreeast" of things.<br /><br />John