Motorguide making noise

[booper]

Several months ago I had problem with motor surging and replaced the module. Also changed brushes and bushing at same time. Unit was resealed with new kit.Recently a high pitched whistling sound has developed. When first start using for maybe the first hour nothing then the "whistling" starts. It seems to be independent of speed as sound is constant while running and sound does not change pitch if speed is changed. Unit operation seems to be fine other than this annoying noise. Occasionally if a hard turn is made the noise will temporarily stop. Any suggestions?

[equalizersmm]

Could be the nose cone

[Bradrodfish]

That noise is coming from the prop. Try a different prop. That noise is common on a 75# thrust. what # thrust do you have?

[booper]

That noise is coming from the prop. Try a different prop. That noise is common on a 75# thrust. what # thrust do you have?

80 lb digital

[Bradrodfish]

80 lb digital

Still could be the prop. Change it and see.

[booper]

Been a while. Just had chance to go to lake after changing prop.. It did not help still making a high pitched whistling sound after about 1 hour of operation. When "cold" makes no noise.

[Jonestrollingmotor]

Been a while. Just had chance to go to lake after changing prop.. It did not help still making a high pitched whistling sound after about 1 hour of operation. When "cold" makes no noise.

And if I read the initial post correctly, the sound does not change with the speed -- or did I mis read? This is a question and not a statement.

[drake322]

Watching.............

[booper]

Yes you read it correctly.. the pitch does not tend to change with the speed of the motor. It has a whistling sound similar to a tea pot. Occasionally it will change pitch when making a hard turn maybe torquing the shaft over?

[Jonestrollingmotor]

Have you by any chance added, or changed the position of, an external transducer on the lower unit.

[booper]

when I rebuilt the motor the transducer was removed and reinstalled. I will check this the next time I'm on the water. I am guessing if this is the source of the noise simply turning sonar off when noise was heard would stop noise? Last time I was out when it was "whistling" I hit run button in stowed position and the noise sounded like it was coming from bottom end.

[booper]

Went to the lake yesterday and the transducer had no effect on the noise BUT the noise is considerably louder know and the noise is definitely changing with the motor. It is still a whistling sound just much louder and tends to get higher pitched as the speed is increased.

[equalizersmm]

Have you tried changing the nose cone?

[Jonestrollingmotor]

First impression, with it changing with the motor speed, is the front end bell (nose cap). it could also be the rear seals rubbing the armature.
John

[booper]

Mr. Jones what would you suggest at this point? Is there a way to isolate the source of the noise or is it simply a matter of tearing the motor back down and looking for the source of the noise? If so do I need to replace nose cone at this point or is there a way to visually tell if it is causing the noise as I am assuming the culprit is going to show signs of rubbing?

[Jonestrollingmotor]

You're not going to see signs of rubbing in the nose housing. What happens is the thrust of the armature rubs against the aluminum nose housing inside the bushing. If you're going to tear it down, I would put some grease on the inside of the seals (through the rear bushing) and change the front end housing.
John