Re: Topic: mysterious overheating OB
Thank you for your response. As follows is exactly what it does:<br />It happens at all speeds generally above 3500 RPMs, and totally at random. <br />Before alarm sounds, looking at Tach you can actually see rpms start to drop.<br />When rpms drop app 300 rpms or so, alarm sounds and engine goes into automatic throttle-back. If I leave the engine running at idle, the horn goes of in a 30 seconds or so. However, I must shut down completely for 2 moinutes to reset the auto throttle-back. Engine does not appear to be in overheat and water continues to circulate. After reset, I can run again for any period of time before it does the same thing all over again. <br />Last time out, I disconnected one of the sensor wires from the right (as you are looking at it) head and ran the engine. This time, while no horn sounded, at about 4000 rpms engine acted as though I were running out of fuel. I would guess that disconnecting that wire disabled the alarm, but there was a problem anyway. Engine slowed to app 2000 rpms then I shut it down. Again, no sign of an overheat. I immediately reconnected the sensor wire to see if the heat alarm would sound -it didn't. A friend sqeezed the fuel bulb while engine appearewd to be starving for fuel and it was completely soft. After shutting down the engine, I immediately restarted it, and it and it ran fine again. We did not have to re-prime the bulb. <br />I called the local repair shop and due to their backlog, have a date of 6/8 to bring it in. Remember, that the season before last I had the same problem. Parts replaced at that time were Water pump, (twice) thermostats, sensors, fuel filters, fuel line from tank, bulb, waterpump again, finally VRO pump. The last time in the shop when both the the Waterpump AND VRO pump were replaced, the throttle back problem went away, but the horn continued to sound intermittantly. The shop then replaced the entire horn mechanism. That solved the whole problem and I ran trouble free all last season.<br />The first time in the water this season, the same thing occurs all over again as stated above. The only things I did were replace the spark plugs and spark plug wires. Wires are genuine OMC parts. In speaking to the Service Manager last week, he feels its definetly a fuel restriction. He is also confident that they'll find the problem this time without getting into the 'replace parts' syndrome as they did 2 years ago. Although its intermittant, he believes he can isolate and fix once and for all. I know I got wordy here, but something has to cure it. Additionally, I know this engine is NOT wired to sound a horn for a fuel restriction, therefore it must be really sensing an overheat, or at least thinks it is. Wisdom has it that by a fuel restriction, it could cause the temperature to rise and sound an alarm. However, as this is intermitant, and the engine runs absolutely fine between these alarm periods, seems to rule out a multitude of problems such as overheats and fuel restrictions. Who knows?<br />Thank you very much for listening, and any help you or anyone else can give is certainly welcomed and appreciated. By the way, you would think OMC would have some fix or repair bulletin out by now. This problem does seem sort of common, No? <br />Thanks again JMACRO.
