That's the reason the law enforcement boats we service now all use aluminum props.

 

Thanks for the replies folks. I have a couple of more questions.

First, the bent shaft is amajor concern that I have. Is there obvious tell tale sign. Once I removed the old prop I cleaned the area and removed all the old oil and grease. I have the motor trimmed almost all the way down so that any leaks will run out the bottom and I can see it. After it sat for a few hours it was still dry so I think that the seals are fine. I spun the shaft by hand and looked for any signs of a crooked shaft. As far as I could tell it was not obviously bent. After I get home I will check to see if it still is not leaking. I also plan on changing out the oil just to be safe.

As far as props go i still have a few questions.
I understand that the first number is the diameter. Every website that I have looked at says that. But none of them explain how this affects the boat's performance. Does it? I assume that it would but we all know what assuming does. I have found a 14 1/2 x 26 and a 14 1/2 x 24 on ebay that look promising. From looking at the Mercury site I think that a 24-26 would be the best overall. I have rulled out the 22 from the local shop, as I think that it would not work very well with what I have. Any other suggestions?

Joe

 

You would definately be able to tell if you have a bent shaft. Unless you havent been able to drive it. Get just about up on plane and you will be able to tell if its bent

Here is a snip about props.

"The pitch of the boat prop is the most important dimension. This usually determines the power and speed of the boat. Pitch is measured in inches and refers to the number of inches a boat prop would move through the water for every revolution. Of course, since water is a very fluid environment, there is always some percent of slippage involved. The diameter of a boat prop is usually a set dimension depending on the pitch and make. Most line of props will go down slightly in diameter and the pitch goes up. The reasoning behind this is that the lighter boats that can run higher pitch props don't need quite the diameter as do the heavier boats. If a boat is using a 14 inch diameter prop, and a 14 1/4 inch prop is available in another brand, as long as the pitch is the same, the performance will probably not change"

I dont know if that is of any use. When replacing props, I just went with what came on it OEM.

Good luck. Hopefully you will get a depth finder. Using your prop is an expensive way to determine depth

 

Wookie, I've got a depth finder that I'll sell to you cheap. It was on my boat, but I installed a radio and ran out of room to mount it. PM me if you're interested.

 

I have a flasher in the console, but it did me little good. It went to zero almost instantly. It shot up so quickly I only had enough time to close the throttle down and start trimming up the motor. I also have a cheap fish finder on the bow but the transducer for it is on the trolling motor so it does me no good. If you have something better shoot me an e-mail I still might be interested.

Joe

 

It's just a basic depth gague with alarm, nothing fancy, it's the kind that you screw onto the back of the boat, and the gague mounts in the dash.

 

Wookie,

The only really accurate way to tell if the shaft is bent is a Dial Indicator. You need to see if the shaft has any runout (wobble) to it. Yes, you could put another prop on and run the boat, but you might not feel the vibration from a minor bend. Professional help might be advised here because this kind of thing can get very expensive if not done right.

As for prop selection, I wish I could tell you a cut and dry way to pick the best prop, but after 45 years of boating, it still comes down to trial and error. The Mercury site has some great guidelines that will help you eliminate most props and zero in on a few. Of those few, the only real way to find the best one is to try them. There's also a ton of production variation in boat props. For instance, a brand new 23" pitch Mercury Bravo prop out of one box can run very differently than the "identical" one out of the next box.

 

Wookie,,

I agree with 2stroked and as I said earlier, selecting a prop is about 90% trial and error. If you were getting good performance out of the prop you have now and the RPMs were within range, I would stick with the same size, or damn near close.

Again, the only true way to check the prop shaft is with a dial indicator. But..a real primitive way would be to start it up and put it in gear and look at the shaft straight on from the back. If its bent, you will be able to see it woddle. Concentrate on the little hole thats drilled directly in the center of the tip of the prop shaft. You will be able to see that move side to side, rather than it running true. Again, this is not the recommended method by any means, but if its bent enough to see the movement, then its bent enough to get it repaired.


BREW

 

BREWDUDE,

Don't you just hate it when we agree like that? Prop selection shouldn't be such a black art, but it is. The number of folks in the country that really understand props can probably be counted on one hand if you're really looking for that last couple of miles an hour.

 

My prop selection is easy, because I can only find one pitch prop for my motor, 1973 Chrysler 130 HP O/B.

 

Yeh man! Ive got a guy here who can get me just about anything I need out of a prop. As long as I give him all the info he needs, he can get me that last Knot, MPH or RPM. But you are correct, it shouldn't be this hard for the everyday boater.


BREW

 

That's sorta what I did, only with the engine off and spinning the shaft real slowly by hand. Once I get home I will check to see if there is any gear oil leaking from the lower unit. Right now I have found several props on e-bay that look promising. Thanks for the help, next time you are down this way I owe you a cold one.

Joe

 

Sweet I'm gonna hold ya to it!!



BREW

 

If you make it this way then your going to be smashed for free....
I owe you 30 or 40 cases myself.

 

I did not get home until well after dark so I could not do too much to check it out. If I need to change out the shaft how much does on cost and how much work does it take? I don't have a manual for the motor, yet, so I am not sure as to how much work it entails. I assume that the shaft is splined on one end with spiral gears on the other. I would think that there are some bearings and seals that are inbetween. I guess that I would be better off to change the seals while I had it apart. I am sure that there is quite a bit more to that area but how much more should I be prepared for? If the procedure is fairly painless I might go ahead and change the shaft just to be safe.

Joe