300r loose prop nut

**city** · 05-09-2021, 08:17 PM

25 daytona twin 300r counter rotating prop nut gets loose after 20 minutes tried new nut and washers anyone have a similar issue or any ideas using hill props thanks

**TooStroked** · 05-10-2021, 11:46 AM

Originally Posted by city

25 daytona twin 300r counter rotating prop nut gets loose after 20 minutes tried new nut and washers anyone have a similar issue or any ideas using hill props thanks

Do you have the correct washers on in the correct order? There's a very slightly convex washer that's supposed to act as the lock washer.

**city** · 05-10-2021, 11:56 AM

The dealer put it on, but he doesn't know why its loosening.
when i checked it after getting the boat back it seemed like he had over tightened it.
the washers are in correct order.
Dealer put a new nut on it, not sure if put new washers on it.
Thanks for your help

**PaulR** · 05-10-2021, 08:05 PM

Maybe your thrust washers are worn, that has happened to me with 2-strokes in the past???

**25two.stroke** · 05-10-2021, 08:07 PM

Originally Posted by PaulR

Maybe your thrust washers are worn, that has happened to me with 2-strokes in the past???

I was about to say the same thing and then realized he probably has the fat shaft hub kit that doesn't have a thrust washer!

Personally I look at the fat shaft hub and I have no idea how it works. I know it does, but I don't get it. Kinda like the 60hp floating prop hub kit...mercury crazy ideas that somehow work.

**PaulR** · 05-10-2021, 08:10 PM

I know nothing about the new motors! lol!

**25two.stroke** · 05-10-2021, 08:52 PM

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This is what the hub kit consists of.

Do you have any idea how many hours are on the hub kit and how long you have been having the problem. I see the main hub part has a black plastic insert...if the nut got loose and the prop wobbled one time i don't doubt it would eat up that plastic part. I would look and see if you can see any visible damage to that. If worst comes to worst you could jamb-nut the prop (2 nuts) but you should not have to do that.

If the problem persists after a change of hub kits then I would reach out to mercury racing through your nearest racing dealer to try to get it resolved before that motor is out of warranty in case the shaft is defective. Mercury has been know to manufacture duds...

**JPEROG** · 05-10-2021, 10:25 PM

Your answer may very well be in your first comment. Have you had the props scanned and trued? I recommend sending them to Frank and Jimmies in Ft. Lauderdale **ATTEN;MIKE E.** and have him true them up. The Hill propellers have had good success with performance but of all the sets that I have seen, there are many inconsistencies with the finish work and blade measurements. I also had a couple of prop nuts milled down and use them as an additional security-losing merc CNCs is not within my budget.

Joe

**city** · 05-22-2021, 05:46 AM

found the torque on the nut was 130 lbs should be 55 belview washer was flattened put a new washer and nut on torqed to 55 and double nutted it to be sure starboard prop nut is so tight i cant get it loose will need an impact gun thanks for all the help