Ranger Man
Cadet
- Joined
- May 29, 2009
- Messages
- 7
I have read thru quite a few posts now on potential idling problems on the OX66 engines, but my problem is a little different. I have twin 1999 225hp OX66 engines (S/L 225TXRX's). The port engine runs great. The starboard engine runs great at high RPM's, but at low RPMs (800-1300) it shakes quite a bit more than the port, and at idle (neutral) I am getting variable readings of RPM. Sometimes this engine will idle high (10-1100 RPM), and other times it will idle low (500-600 RPM). The idle speed, whether in neutral or in gear, will change almost every time I turn the key switch on/off. Sometimes, if the engine warms up, the RPM's will drop back to normal range, and stay there throughout the day. Other times, they will vary -- tending to run higher
(900-1100). I have adjusted the idle set screw many times, and this does not seem to make a difference. Sometimes I can't even adjust the setting low enough to drop the RPM's into normal range. I can set the screw, and have to adjust it 15 minutes later. I brought the boat to a 5 star Yamaha shop recently, and they adjusted the TPS sensor and made a few minor cable adjustments, but the problem still exists (better, but still not right). No codes were obvious on the flash reader. One other problem that is troubling me is that on this same engine, I am getting a 2-3 second "dieseling" run-on effect after shutting the engine off. Not every time, but probably 5 times out of 10, it will run for an additional 2-3 seconds after turning off the key switch. The port engine does not have ANY of these problems. Any ideas/feedback would be greatly appreciated! I am not sure what is going on at this point, and am not sure if the problems are related in any way or not. Since most of these parts (O2 sensor, ignition switches, TPS sensor) are expensive, I would like to have a bit more direction before I start replacing parts to troubleshoot. Also, just as an FYI, the engines both reach 5400-5500 RPM WOT, and push the boat in the mid 50's top end speed. No problems with horsepower or compression. All cylinders compress between 115-120. I don't have any service history on the boat. Bought it used just a few months ago. The idle and run-on issue on the starboard engine has me concerned, and I'm having trouble isolating the problem. Thanks in advance for any suggestions you may have!
(900-1100). I have adjusted the idle set screw many times, and this does not seem to make a difference. Sometimes I can't even adjust the setting low enough to drop the RPM's into normal range. I can set the screw, and have to adjust it 15 minutes later. I brought the boat to a 5 star Yamaha shop recently, and they adjusted the TPS sensor and made a few minor cable adjustments, but the problem still exists (better, but still not right). No codes were obvious on the flash reader. One other problem that is troubling me is that on this same engine, I am getting a 2-3 second "dieseling" run-on effect after shutting the engine off. Not every time, but probably 5 times out of 10, it will run for an additional 2-3 seconds after turning off the key switch. The port engine does not have ANY of these problems. Any ideas/feedback would be greatly appreciated! I am not sure what is going on at this point, and am not sure if the problems are related in any way or not. Since most of these parts (O2 sensor, ignition switches, TPS sensor) are expensive, I would like to have a bit more direction before I start replacing parts to troubleshoot. Also, just as an FYI, the engines both reach 5400-5500 RPM WOT, and push the boat in the mid 50's top end speed. No problems with horsepower or compression. All cylinders compress between 115-120. I don't have any service history on the boat. Bought it used just a few months ago. The idle and run-on issue on the starboard engine has me concerned, and I'm having trouble isolating the problem. Thanks in advance for any suggestions you may have!