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8hp Nissan squalls with new prop

L

Luckydog

New member
I bought a new prop from Paul, identical to the old one, and now a get a sight squall out of somewhere. It only happens in forward and starts just slightly above idle and disappears upon further acceleration. It is not coming from the powerhead anywhere, speaking of the rubber belt. I removed the prop to double check everything, thrust washer, then the prop, then the washer, then the castle nut, snug it down then backed it out slightly to align the cotter pin hole.

Any ideas? Performance seems good, no unusual vibrations. Everything else seems fine.

David
 
IIRC, you have an NS8A, (4-stroke) right? If so, you are probably getting a whistling harmonic in the intake manifold, at around 2,000 RPM. If so, the situation is very well-documented, is being looked at, and the factory engineers in Japan have yet to come up with a suitable solution for it.

If you have an old 2-stroke, please drop me an email at the office: [email protected], (or call 716-877-8221 M-F 9-7 Eastern), so I can diagnose the sound, and possibly get you a replacement prop. Did we change pitch at all when you got the new prop?
 
Probably the same whine. The one in the video sounds like the intake harmonic whistle that some MFS8/9.8 motors have. Because the 4-stroke motors are so quiet overall, the whine becomes noticeable. If it were a noisy, smoky 2-stroke, a sound at that level wouldn't be discernible above the rest of the motor's sounds.
 
All true ... the motor runs so good I Can't believe it ...

Thanks for a quick answer ...






pvanv said:
Probably the same whine. The one in the video sounds like the intake harmonic whistle that some MFS8/9.8 motors have. Because the 4-stroke motors are so quiet overall, the whine becomes noticeable. If it were a noisy, smoky 2-stroke, a sound at that level wouldn't be discernible above the rest of the motor's sounds.
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