Can you reuse the prop nut that secures the propeller to the shaft?

LaRea

The "book" answer, quoted recently on this forum, is:  No, the propeller nut is a single-use item and should not be reused. 

That's news to me, and I've never heard of anyone replacing prop nuts as routine annual maintenance.  So I'm wondering:  Why?  On which drives?  What's the risk if you reuse it?

I've had Bravo 3 drives on a 342 (10 seasons) and a 370 (8 seasons).  Every spring, I remove the props for maintenance, and reinstall them using the same prop nuts.  Every time I remove the nuts, they are exactly as tight as when I installed them.  After I loosen them, it's impossible to spin them them by hand ... a wrench is required.  I can't imagine they could ever back off on their own.  

To me, annual replacement seems like a waste of $40, but I'm willing to be convinced otherwise. 

Willhound

I side with you @LaRea. Properly torqued they can last many seasons. Mine is original I believe. Would be evident I think when they are done.

Liberty44140

x2 I always re used 

reneechris14

I agree with @LaRea the the nut spins on easy till they get to the nylon then a wrench is required to get to the torx spec. 5 years with my 270 and 5 years with my 342 and I have removed my props and drives every winter. Nuts are just as tight as when the went on.

aero3113

In aviation a nylon lock nut is one time use. On a boat, if you thread it on and you still feel resistance at the nylon I would say your still good to use it. 

Cableguy Greg

I have never replaced the prop nuts on my drive. This is my 7th season with the boat. They look original to me, but I am not sure what the PO did. All I know is that he had the fluids changed every year and the boat washed and waxed each spring. If I was a betting man, which I am not, I would say that they are original. 

PickleRick

I work on hedge trimmers. They use multiple locking nuts.  Usually 8 to 10 that hold the blades to the blade bar. Years ago some manufactures used nylon lock nuts.  Stihl, and their German engineers, went to using crush lock nuts.  


Even when properly torqued, reused crush nuts are known to vibrate loose. Maybe one or two. Luckily there are many more to hold the blades on hedgetrimmers. Unfortunately our props where there is only one.

Reused nylon nuts came loose constantly.

I went to using only brand new crush nuts on all brands with a dab of blue loctite, issues went away.

I do the same on turbo down pipe mounting studs, exhaust studs and turbo mounting studs.  

Having lost a prop before (luckily on a sailboat) i wouldnt risk it.  

You can recrush your lock nut if needed, ive even crushed regular nuts when in pinch.  

I guess my point is if there is a lot of heat or a lot of vibration involved i go the extra step and replace.

My alpha 1 has a spider ring with tabs i lock in place so i dont have the issues you guys have with your bravos.  My prop is also half, maybe even a 1/4 of the cost of yours.

I may be a little ocd.  

If i was going 10 miles off shore fishing and found the guy was reusing nylon lock nuts on his props I'd find another boat to go with another boat.  

At least use some loctite(blue)

You can get stainkess lock nuts at your local fastener supplier or online.  Probably not a bad idea to keep one or two in your junk drawer, you may not need it but may help a fellow boater in need.

PickleRick

i cannot edit my typos.

Handymans342

Bravo 2s are a totally diff setup

212rowboat

on a similar note, i happen to know a guy right now who used grade five bolts to attach his lower foot to his gear box... all four of them (he decided the one above the rear anode and behind the front anode was overkill by the engineers)... he used regular lock washers on those grade five bolts. 

want to guess where his lower foot is right now after three or four seasons in salt water? 

he's been 'looking' for it for about a week now.  my guess is it hit the bottom and sank in the muck, there... and since it's in a channel that changes seemingly by the hour with tides and the massive amount of traffic it sees, well, it's a goner.  the bottom is around 20' deep there... i'm guessing the foot is at least 24' deep at this point.  

who knows.... maybe he'll get lucky and find it.  

i'll be curious to see how he fastens the replacement foot on that thing. 

back on point:  alphas tighten as they spin forward.. reverse is when you'll discover your fastener is weak.  B3's have some strange harmonics... i don't have a clue what to suggest. 

PickleRick

Lost a bravo foot...sounds not cheap.  As much as i knock the alpha outdrives they at not only cheap to replace but easy to maintain.  They are very reliable outside the ones  paired to big blocks in sting rays.  

LaRea

Okay.  I was worried that the rest of the boating world was treating prop nuts as single-use, and I was the village idiot because I reuse them.  Good to know there are other idiots out there.  

aero3113

LaRea said:

Okay.  I was worried that the rest of the boating world was treating prop nuts as single-use, and I was the village idiot because I reuse them.  Good to know there are other idiots out there.  

LoL!

PickleRick

@LaRea has a spare motor...he can afford to take a little risk 😂

goalie59

I have always reused the nuts and torqued to 100/ 60 ft lbs as per Mercury. One fall a few years ago the forward nut had backed off, motto the point that the prop was loose but it kind of freaked me out .i replaced both nuts and noticed that the new one took a lot more pressure to turn once I hit the nylon lock. The nylon strop on the old nut had worn down quit a bit. I guess for me it was time to replace. Moral of my story is to inspect the locking part of the nuts when pulling off 

bry1429

 This is what happens when you don't torque the nut down on your stationary bike

bella-vita

Take mine off every year , torque to spec, never replaced. 

LaRea

Maybe there's a certain number of times they can be safely reused?  (Assuming annual inspection, of course, and replace if they move too easily.)

rasbury

It's just a nut right?

LaRea

On the B3, it's a specialty fastener.  One side is tapered to fit the prop.  The other side has a fitting to attach an anode.  Seems you can only buy it with the anode, and they cost $60-$90 each on Amazon.

For older B3 drives, without the anode, you can buy the nut for $20.

There's no cotter pin.

Willhound

shawnmjr said:

Doesn’t the cotter pin keep from backing off? 

No cotter pin. On a B3 anyways.