Force 125 1985 prop nut is backing out

I need some help. Motor was running great 2 days ago. Today I head out and only half power at wot in forward. Reverse s?ems to rev just fine. Put the boat back on the lift and looking at the prop the nut seems to have backed itself out. I also found a small Allen head cap screw wedged in the exhaust port of the prop that I know attached to the lower unit. My question is what to do next other than tighten the prop nut after inspecting the splines and replacing the cap screw. How do I prevent this from reoccurring.

Re: Force 125 1985 prop nut is backing out

Can you post a pic?

Re: Force 125 1985 prop nut is backing out

There should be a cotter pin installed thru the prop shaft threads that prevents the nut from backing out. There is a hole in the threads(look for it)....that's where the cotter pin goes.

Re: Force 125 1985 prop nut is backing out

Most 80's Force don't have a cotter pin setup.Older ones do.
They use a NYLOCK nut.If it comes loose replace or add sillycone to help stop it from backing out.
Older Chryslers use the cone and have a pin/key.

Re: Force 125 1985 prop nut is backing out



Listen to me: There is no hole for a cotter pin at the prop nut. The nylock insert is worn past its locking ability. Buy a new self locking prop nut and use it.

Now: Unless your lower unit was changed, there should be an extended prop shaft to take a flare washer and tailcone. While these two pieces will not keep a propnut from loosening, they will keep it from backing out completely. If you do not have these, there is a hole in the shaft through which you can install a large cotter as a safety so if the nut should back off, you still will not lose the prop.

If your lower unit was changed and you have the short shaft, you can find a prop with a Mercury style hub and use the mercury locking washer and propnut. Later force engines use them.

The small allen head screw, if it was about 1/2 inch long, was probably from the anode. Behind the prop there is a circulat zinc anode held by two screws. Usually they are slotted head fillister but someone may have replaced them with allen head.

Re: Force 125 1985 prop nut is backing out

Thanks Frank.

I replaced the lower unit with an original style one but no tailcone any idea where to find one?

Re: Force 125 1985 prop nut is backing out

Obsolete part but occasionally they will come up for sale on the auctions. They were about 30 bucks new and usually about the same price at auction

I do have three but because of the difficulty in finding them, they are pieces I would not consider selling.

If I had a Lathe, I would make a couple out of plastic bar stock or aluminum.

Re: Force 125 1985 prop nut is backing out

Not to threadjack, but is the black plastic tailcone supposed to be tight, or that it can turn on it's own a bad thing?

Bob

Re: Force 125 1985 prop nut is backing out



The Flare washer should be splined and takes the place of the metal spacer. I always buy an extra-thick stainless fender washer to fit the inside diameter. It will not crush the palstic as much as a regular washer. You can see it in the close-up of the bronze prop.

The tailcone itself simply slides over the extended propshaft. It is held onto it by a screw exactly like the one in the side of the gearcase that holds the shift yoke--you know--the one everybody always removes by accident to drain the oil. You can not see the screw in the photos but can see the recess for it in the tailcone.

While the tailcone is not snug against the flare washer, It is not loose either and can not spin because of its retaining bolt.