prop nut backing off ?

[pickwickangler]

My prop nut keeps backing off.I am runnin a 28 drag4.About every 2 trips i have to tighten it back up.I got a new prop nut and lock washer.Previous owner said it did the same thing with him.I have to make a 50 mile one way tourney run next weekend and I am a little worried about it.Would it be ok to loctite it on?

 

[BigRedAlli]

What kind of hub is in your drag-4? Does it have a recess for a tab washer or just flat?

 

[pickwickangler]

It has a tab washer.I am using one and the tabs stay where i lock them in at.I put some loctite on it because i got a tourney in the morning.It dont make sense to me how it gets loose with the tabs still down.I cant never have something simple screw up its always off the wall

 

[John Richied]

The Loctite should make no difference since the locking tab washer won’t let the prop nut turn. How much have you torqued the prop nut down too? If it’s a newer prop and it has never been torqued to more then the standard 55 lbs. or so the hub maybe slipping in toward the thrust washer causing play. Try 70 lbs and see if that makes a difference… after that 55 lbs should be good.

Also when you torque down the prop nut and the tab washer doesn’t line up (never does) tighten the nut to the next tab… don’t back the nut off.

If all of this checks out fine maybe you have the wrong thrust washer for that prop?

Good luck in your tournament! :wink:

 

[pickwickangler]

The thrust washer is a yamaha style i think.It has a ring that fits into the prop but when the prop is a little loose there is some slop in it.I tightend the #$#$ out of it.Thanks for the help.

 

[ALLISONMAN]

i think you might have the wrong thrust washer!! the drag 4 thrust washers have a small area that pushes up against the center of the hub!!! there is no way for the prop nut to back off !!!! you are having a hub issue and i would probably send the prop off and have it checked and run another prop before you are changing props on the lake!!!!

 

[TnRiver03xb]

I had the same problem when I was runing a small shaft. I found that the inside taper of the thrust washer would fatigue and allow the thrust washer to move foward. If you have axcess to some precision measuring tools compare your old one to a new one, (Inside Diameter). That may find your problem, however I never found a washer the would not fatigue. I checked prop after each outing and replaced the washer often.

 

[lightening rod]

Mine does the exact same thing as tnrivero3xb, the thrust washer will fitigue and slide further up on the shaft than it is supposed to. I finally figured this out one day when my washer finally got up far enough to hit my gearcase, made this real purty sound when I put it into gear. I had noticed it loose, but just kept tightenin it up. Hope this helps.

 

[whipper]

thrust washer

I have the same trouble on mine. I changed props to the one without the tabs and reused the thrust washer I torqued the prop on to 75 lbs and after 3 hours it was loose 25lbs. When I took the prop off the thrust washer was further down the shaft and jammed on there to tight to take off by hand so I left it there put the prop back on torqued to 60 lbs and next day after boating hard runs got home torque was 60 lbs. I figure the thrust washer must have to be tapped down a bit before the prop? Any way It was obvious that the nut never moved the washer slid down. I'm going to mark the thread next time I use that prop to test that theory out. Later James

 

[RedAllison]

Damn now you guys dun give me sumpin else to be paranoid about, sumpin else to check and replace! :wink:

So with that being a multiple incident, would having some stainless steel thrust washers made up be the answer? If so I'm sure all of us have buddies with machine shops and can have some made up.

BUT then on the other hand, that wear and force has to go somewhere. Are the brass thrustwashers a sacrificial piece? If so then obviously it would be better to keep some extras handy than wear out a propshaft!

Speed costs... how fast you wanna go? :roll:
RA

 

[John Richied]

I believe you guys are right that... the thrust washer is being forced further and further on… hence the prop being loose.

And the brass thrust washers a sacrificial piece, buy a few and when the old ones get worn toss them.

Ever notice how sometimes the brass thrust washer is a my mom to get off… and other times especially when they are new a little tap and they come right off.

I am sticking with the original 55 lbs. of torque for the prop nut with the regular 1” prop shaft and locking tab washer.… the 75lbs or someone said 120lbs. is just going to force the brass thrust washer further up the prop shaft…. LOL

 

[pickwickangler]

You guys were right my STEEL thrust washer was wearing out.My best cure was to torque the prop nut over 100 ft lbs.It still loosens up but not as quik.I wont go out any more without checking my prop.If you run one loose you can break your prop shaft so keep a check on em.Thanks for every ones info.

 

[froggy]

The older Merc hubs (before flo-torque) are surrounded by a rubber shock absorber. These hubs have a tendency to rotate (slip) inside the propeller housing. This rotation works the thrust washer like a lathe would. Eventually they just let loose and your boat won't move at any speed faster than idle. Heavy loads and lots of horsepower cause this slippage. The new propellers have flo-torque hubs which remedy this problem.

When in doubt, have your older style prop rehubbed.

froggy