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9.8 Low Pitch Whine/Whistle

stevennh

New member
I picked up a Tohatsu 9.8HP 4-Stroke this week and started break-in yesterday. I am getting a whine/whistle (sound like air movement) at low RPM (just above idle). It's not crazy loud, but it's noticable. The motor seems to run great. Has anyone else noticed this sound? It only occurs at a narrow RPM range (about 1000-1200 RPM).
 
Yep. The timing belt can whine a little during the first 20 hours or so on some of these. Sometimes happens about 2,000 rpm, sometimes lower rpm. Nothing to worry about. Goes away after break-in.
 
I also have that noise on my 9.8 Tohatsu. It hadn't gone away after about 30 hours of operation. It seems to do it only when in gear. I can rev up the engine in neutral without the noise. I took it to back to the dealer yesterday ( hadn't found this site) for warranty. It will be interesting to see what he has to say.

Mike
 
I've noticed timing belt whine on a few 9.8's, including mine, during break-in. Usually happens when loaded (not in neutral), and is usually present only in a particular RPM range. Because these motors are so quiet, any noise, including the belt whine is more noticeable. The whine should go away in time, as the cogs of the belt and pulleys mate to each other.
 
I didn't verify the noise when I dropped off the motor. Repairman couldn't duplicate the sound but sprayed the belt with silicone. Went back this morning and didn't here the noise in the test barrel. Dealer charged $50 for his time ! Shouldn't this be covered by warranty? The dealer must have heard something or he wouldn't have sprayed the belt?

Mike
 
The timing belt is supposed to run dry. No belt dressings or other sprays are called for. Not sure what "silicone" your mechanic used, but hopefully it won't cause problems. All gear drive systems have a characteristic whine of some sort, and the timing belt is no exception, although it typically subsides as hours accumulate and the belt breaks in. In our shop, we don't consider a minor, low-pitched belt whine on some of these to be a malfunction, so it would not be repaired at all, unless loud or objectionable. In that case, we would inspect/replace the belt and/or pulleys as needed. As for the warranty question, if you are within the warranty period, you should ask for any repair service to be covered under warranty, unless it's a result of things that are beyond the manufacturer's control (for example carb varnishing due to poor fuel, etc.)... BTW, to get a repair of any nature on any OB for only $50 is not a bad price. Our hourly rate is $75
 
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