prop question

[lathehand]

Hi i have a 1977 150 hp merc.I need to replace the prop.But the old one has been on for so long i cant get it off.It seems to be frozen onto the spline.I tried spraying pb blaster and letting it soak but still wount budge.Can anyone give me some ideas.I can't beleive something as simple as removing a prop could give me this much greif

 

[huntin dawg]

Re: prop question

Heat it with a torch. You may have to heat it enough to burn the rubber core out of it so it will come off. Then you can use a puller to get the hub off the shaft.
When you put the new prop on make sure to put grease on the shaft.

HD

 

[Silvertip]

Re: prop question

And as you are burning up the rubber you are also burning up the prop shaft seals. There is a way to do this much more easily. Loosen the prop shaft nut so there is about 1/8 inch clearance between the nut and the prop. Then run the boat, accelerating and dropping back repeatedly. The push pull forces will sometimes loosen a stuck prop.

 

[lathehand]

Re: prop question

Thanks gents I really didn't want to take a chance on useing a torch.There's nothing wrong with the lower unit.I had thought about backing the nut off and running it a little but wasn't sure it would be better if the boat was in the water or on the muffs

 

[Chris1956]

Re: prop question

Tilt the motor up and remove the prop nut. Saturate the splines with PB Blaster and let her sit a couple of days. Now use a 2X4 to pry between the gearcase and the blades of the prop. The soft wood will not damage anything. If that fails, you can try Silvertip's method or a puller. How about a loose prop nut and some reverse, when in the water?

 

[Moody Blue]

Re: prop question

Another approach that may work is as follows.

Quite often a steady pull or push won't "free" a stuck part. A sharp "rap" will.

Remove the prop nut and reinstall it backwards (nylon locking side in) till flush with the end of the shaft. Place a wooden 2x4 between the prop and the housing as it you are trying to pry the prop off. Apply pressure to the 2x4 and using a hammer, smack the end of the prop shaft. You need to hit it pretty hard but don't smash it. Use common sense. The jarring action just may pop it free.

 

[lathehand]

Re: prop question

Thank you everyone for your advice.I finally got the prop off.The reason I had to take it off was to replace it one of the tips were broken off.I have another prop but it's much smaller in diameter than the broken one.The only numbers that I can find on the broken one is H3629 I don't beleive it's a merc number and there's nothing readable on the small one .It does fit on the spline but I'm afraid of over reving with it.Can any one tell what would be the proper pitch and diameter prop for a 1977 merc 1500 on a Wellcraft v20 step lif it weighs 1920 lbs.