HTHM Posted April 14, 2011 Report Share Posted April 14, 2011 When tightening a prop nut on a high horsepower motor, how tight does it need to be and are there any common mistakes made with the "tang" washer? I am going to be experimenting with two props on the weekend and do not want to leave ~$450 on the river bottom... Link to comment Share on other sites More sharing options...
FisherMike Posted April 14, 2011 Report Share Posted April 14, 2011 hand tight with a cotter pin should do the trick. thats how we do it at the lodge i work at. Link to comment Share on other sites More sharing options...
Bernie Posted April 14, 2011 Report Share Posted April 14, 2011 Tighten it until the thread strips, then back it off a half turn. Seriously though, on mine I set it to 80 lbft. Take a couple extra cotter pins of the correct size, preferably stainless. After a couple of bends I don't trust a cotter pin to stay in place, especially when dealing with the expense of a propeller. Link to comment Share on other sites More sharing options...
HTHM Posted April 15, 2011 Author Report Share Posted April 15, 2011 This prop shaft does not have a cotter pin hole that I have seen. It has a locking washer that has tangs on it that are bent back to lock it in place. The retaining nut is a nyloc nut as well. Link to comment Share on other sites More sharing options...
vinnimon Posted April 15, 2011 Report Share Posted April 15, 2011 Looking threw my manual(mercruiser) The torque specs varies depending on what model gear housing you have. It ranges from 18 ft/lbs to 55ft/lbs of torque. Use stainless cotter pins and never, never reuse them if they are removed. Call your lacal dealer for proper specs, and have the engines serial # handy. Link to comment Share on other sites More sharing options...
Terry Posted April 15, 2011 Report Share Posted April 15, 2011 just tighten it down then line up 3 tabs and knock them into place Link to comment Share on other sites More sharing options...
morieris Posted April 15, 2011 Report Share Posted April 15, 2011 On my Mercury 75 4 stroke the torque is 55 lb/ft Link to comment Share on other sites More sharing options...
fishinguypat Posted April 15, 2011 Report Share Posted April 15, 2011 2 years ago when i got a new to me boat, i got out on the water and somehow the prop fell off, it turned out the pin was not attached so when we reversed it fell right off. I always check now Link to comment Share on other sites More sharing options...
Terry Posted April 15, 2011 Report Share Posted April 15, 2011 well now he know to check the pin to bad he doesn't have one.... Link to comment Share on other sites More sharing options...
Old Man Posted April 15, 2011 Report Share Posted April 15, 2011 55 ft lbs Link to comment Share on other sites More sharing options...
fish_fishburn Posted April 16, 2011 Report Share Posted April 16, 2011 My 175 EFI Merc shop manual says 80 lbs. I have had it on and off so many times over the years that now I just tighten really tight with a 1/2 drive rachet and never a problem. You must be able to bend at least 3 of the lock washer tangs upward to keep everything where its suppose to be. When you find the prop your going to keep, after a few times out bend the tabs down and snug the nut up again, bend the tangs back up and your good to go. Some marine greese on the spline is always a good thing as well. Link to comment Share on other sites More sharing options...
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