new upper gear set humming

[erikincider]

new upper gear set humming

just replaced upper gear set and have a slight humming noise. I installed using shimming tools and set driven & drive gears to .025 The only thing I could think of is a bearing humming since I used old bearings and races. 1986 stingray ss 2.5 gm mercruiser alpha 1 generation 1. Is this a normal noise just got boat never had a i/o boat

 

[moderator1]

Re: new upper gear set humming

Re: new upper gear set humming

Moving to I/O questions.

 

[denniz]

Re: new upper gear set humming

Re: new upper gear set humming

did you check the bearing preload before you shimmed it?

 

[Capt Ken]

Re: new upper gear set humming

Re: new upper gear set humming

Probably nothing is wrong. Just a little more parinoid now and every little noise is making you nervous. Probably humming due to the gears not knowing the words to the song.

 

[The Marine Doctor]

Re: new upper gear set humming

Re: new upper gear set humming

Noise from gears is not good. Did the old brg's hum with the old gears?<br /><br />Did you use a manual when you assembled the new gears?<br /><br />TMD

 

[denniz]

Re: new upper gear set humming

Re: new upper gear set humming

Had to read that twice capt ken b4 I got it. ha

 

[erikincider]

Re: new upper gear set humming

Re: new upper gear set humming

i did not check preload with a torque wrench but they spun freely where can i find a torque wrench 0 to 45 inch pounds cheap? the old gears where stripped when i bought the boat so i never heard it run before i did the gears i read the book inside out rechecked the shimming to be sure

 

[denniz]

Re: new upper gear set humming

Re: new upper gear set humming

bearing preload is done with a dial type torgue wrench. AINT CHEAP probably cheaper to have it checked.

 

[erikincider]

Re: new upper gear set humming

Re: new upper gear set humming

nobody will touch it unless they do the whole job

 

[denniz]

Re: new upper gear set humming

Re: new upper gear set humming

have you tried ebay for the torgue wrench?

 

[The Marine Doctor]

Re: new upper gear set humming

Re: new upper gear set humming

There is a special rolling torque that must be used when assembling those gears. If this is not done correctly a hum will be created while the engine is running. Remove the top cover and inspect the gearset.<br /><br />As I said before...a hum is not a good thing.<br /><br />Also...isolate the sound...find out if its really comming from the gearset.<br /><br />Some Mcruisers make a hollow whining noise which is normal.<br /><br />TMD

 

[erikincider]

Re: new upper gear set humming

Re: new upper gear set humming

I listened to it with solid piece of pipe and found the noise coming from the drive bearings i ordered new bearings and racers and found a dial type torque wrench . never had the boat in the water yet

 

[erikincider]

Re: new upper gear set humming

Re: new upper gear set humming

i used a in pound tourqe wrench and preload is right at 10 in pounds and gears are at 025 is there a break in peroid for new gears that noise will go away

 

[djvan]

Re: new upper gear set humming

Re: new upper gear set humming

I just replaced my lower (mercruiser) unit. The break in procedure for it was as follows::<br /><br />Vary rpms for the first 5 hours<br /><br />Do not exceed 3/4 throttle for the first 5 hours<br /><br />Shift into forward gear and reverse gear at least 10 times in the first 5 hours<br /><br />After 5 hours is up::<br /><br />Avoid extended periods of full throttle for the next 5 hours.<br /><br /> I would think the shifting at least 10 times would not really apply since it is the upper you are dealing with.<br /><br />HTH's<br /><br />DougV>