View Full Version : Spare Prop Install

05-21-2006, 10:03 PM
I messed up one of my blades on the prop today. The second outing ever on this boat that I bought 3 weeks ago. ARRGH!! Just got it off the trailer and was makin my way over to the dock and BAM one of the blades got whacked... Day done!

So anyway I took off the bad prop and put on the spare prop. Now for my question....

Of course I didn't mark the prop where it was initially. Didn't think of that gem until I realized what I am going to explain....

When I put the spare on as far as I could press with my hands, it just seems like there is a much bigger gap from the back of the prop "collar" to the "strut". So if you could push the prop as far as it could go it would stop because of the strut around the shaft would stop it which is located behind the prop and is attached from the hull and braces the shaft. So the gap from the back of the prop to the strut is currently 3/8".

Anyway, I do remember that the old prop was further back with a much smaller gap than what I have now with the spare prop. It was probably about 1/8" would be my guess. Granted the props are different but they do have the same specs 14 - 8 cup, etc but the length of the shaft for both props are the same as you would expect.

I haven't done it yet but shall I gently bang it back closer to that strut to get about 1/8" gap? I was thinking about using a PVC pipe to fit around the nut and shaft not too big as not to touch the blades but to fit nicely around the collar of the prop and then hit the end of the PVC pipe to push the prop back farther to close the gap.

Should I do that approach and if so how far do I go back too or what should that gap be or does it really matter?

Or...can I just press it on as far as I can and then tighten down the nut and put in the cotter pin and call it a night? The prop goes just past the threads for the nut so I can put the nut on.

I just dont want to put on the prop and have it way out of whack and then the next time I go out I mess something else up because of 1/4". The manual just says put it on but doesn't state gap so that is why i just thought you just put another one right back on and everything will fit like a glove.

She is a 93 Prostar 190 if that helps any.

Thanks for any advice!


05-23-2006, 06:24 PM
So an update.....

I have talked to 3 people regarding this. 2 say put it on as far as it will go put the nut on and torque it and put the cotter pin in. The other, who works for OJ props, says that there should be a distinct PING when you put it back on. I believe the guy who works at the prop place but I cannot get this "PING". I have filed the key on all sides so that it rides smooth in the grooves of both the prop and the shaft but when I get to a certain distance I can no longer push it further to snap it on to make that sound.

What am I missing here? Anyone else ever put on a prop and have to get that PING? He says that if I don't get it on there with the "PING" sound then I will probably have vibration which is not good.

Any suggestions?

I have greased it all up and literally have tried over and over for at least 50 tries for 2 1/2 hours.

Please help...very frustrated here.



05-23-2006, 06:58 PM
OK, let's try something, turn the propshaft till the key slot is on top, place the key in the slot, place the prop w/ key slot on top gently on the shaft with a finger on the key so it won't move forward and slide the prop forward till it won't go any farther over the key on the shaft. Be sure the key is not forward of the prop hub. Put on the propnut a few threads to be sure prop won't fall off, but do not tighten yet. Grab the propshaft forward of the strut with one hand and try to rotate the prop with the other, if the prop is locked on the propshaft by the key and rotates the shaft then everything is in place, tighten the propnut and install your cotter key. DO NOT DRIVE THE PROP UP ON THE SHAFT!
As far as the clearance between the prop hub and the strut it could be because of the difference in the prop you are replacing, just be sure they do not touch. Are you using the right prop for the shaft size as there are props for 1" shafts and 1 1/8" shafts and this could cause the decrease in clearance between the prop hub and the strut? Is the replacement prop the same brand and shaft size as the original?
I am not aware of a ping when a prop is put on, maybe never noticed! When removing a prop with a prop puller, you will hear a ping when the prop releases from the shaft if it is on real tight. Never remove the propnut completely when removing a prop with or without a prop puller, because when it releases and there is no nut to stop the prop on the shaft it will come off and hit everything in it's way to the floor, the rudder, trailer propguard and fingers, if you try to catch it!
If you ever have a prop that just refuses to come off, spray the shaft and the prop hub forward of the prop with WD40 and let it sit for a few minutes and if it still won't come off, SLOWLY heat up the hub of the prop with a hairdryer, heatgun or a propane torch and the heat will expand the hub and release the prop from the shaft.
When you get home from your first trip with the newly installed prop, check the propnut and tighten if necessary as the prop may force it's self forward on the shaft slightly, usually it's never noticable!

05-26-2006, 08:24 PM
Well I just put it on and took her out. Tuned her up and she is running good. No vibrations at all. ;)