Boy, did I pull a dumb one!

[iwombat]

Re: Boy, did I pull a dumb one!

It's likely that your LU just overheated, expanded and seized. Whether it did any disasterous damage is unknown. Fill it with oil, and pressure test it, since the overheat may have toasted the seals. If it turns freely, and you don't get any crunchy bearing noises it's worth giving it a try.

You might want to flush with diesel first and see if you can flush out any chunky metal bits. That'd be a sure sign of something toasted.

 

[rnvinc]

Re: Boy, did I pull a dumb one!

How do I pressure test the lower unit? Thnx!

 

[iwombat]

Re: Boy, did I pull a dumb one!

You basically hook a hand-pump to one of the fill plugs off a LU lube pump. Put the whole thing under water and pump to about 10psi - watch for bubbles.

 

[HighTrim]

Re: Boy, did I pull a dumb one!

To pressure/vacuum test a lower unit:

a) drain the gear oil
b) use an appropriate adapter with a gauge tee'd in to apply pressure or vacuum. I personally use the adaptor from my lower unit oil pump kit. No more than 15 psig for pressure. You can use a bicycle pump or any other compressed air source for pressure. For vacuum, you need a vacuum pump.
c) LU should retain some pressure or vacuum for 45 minutes minimum.
d) If pressure doesn't hold, submerge LU in water to find leak source [possibilities: drive shaft seal, prop shaft seal(s) (usually two), shift shaft seal and the fill/drain screw washers.]
e) replace offending seal(s) as required.

EDIT: Sorry Iwombat, typing at same time

 

[rnvinc]

Re: Boy, did I pull a dumb one!

Thnx guys! I will try that tomorrow and get back with you.

 

[rnvinc]

Re: Boy, did I pull a dumb one!

I decided to follow iwombat's advise and fill the LU with diesel and see what drained out with it.

I put the LU upright and filled with diesel thru the bottom hole until it came out the top hole.

Then I rotated the verticle shaft several turns in neutral, forward, and reverse......then drained the LU....oil was dark but no metal pieces.

I refilled with diesel again and rotated shaft several turns again..then drained LU again...drainage was now same color as diesel going in...still no metal.

I notice that it still takes some slight force to rotate the verticle shaft but there are still no hard spots or grinding noises. It feels as if the seal around the shaft is just smaller than it should be thus squeezing the shaft. I also notice that the force it takes to rotate the shaft is constant and not "grabbing and releasing".

I then refilled the LU with diesel a third time and let it sit overnight.

This morning I drained the LU...drainage was still the same color as the diesel going in...still no metal.

I refilled the LU a fourth time and ,once again, rotated the vertical shaft....still no odd noises or grinding but it still takes about the same amount of force to turn the shaft.

Does this sound like it may be just the seals overheated and expanded?

Is this something I can undertake myself with regular hand tools?

 

[Gary H NC]

Re: Boy, did I pull a dumb one!

The shaft is usually a little hard to turn by hand.
Pressure test it and see what you got.You may get lucky and get more use out of the lower...

 

[rnvinc]

Re: Boy, did I pull a dumb one!

Pressure tested the LU...

Submersed the LU in water and pressurized to 20psi....no bubbles anywhere

I even rotated the shaft in neutral, forward and reverse while pressurized under water and still ...no bubbles.

I let LU sit pressurized under water for 30 minutes...no loss of pressure on the guage ...and still no bubbles.

How much resistance should I feel when trying to turn the shaft by hand?

 

[iwombat]

Re: Boy, did I pull a dumb one!

From what you describe, I think the LU is good to run as-is.

 

[rnvinc]

Re: Boy, did I pull a dumb one!

Should I add some kind of "seal fixin product" (if there is such a thing) or just use lube....

I normally use LubriMatic Power Pro Synthetic Blend Lower Unit Gear Lube.

 

[Benny1963]

Re: Boy, did I pull a dumb one!

use good lower oil and run it .

 

[rnvinc]

Re: Boy, did I pull a dumb one!

Have to go back to work today. I'll follow up when I can...thnx