Prop Question - 1970 Evinrude #25002C, shear pin

[D_Loomis]

I have a 1970 evinrude 25hp. model 25002C, the prop is in great shape, but the [bushing?] in the back of it where the shear pin rests is worn. Whenever I put it in gear it shears off the shear pin. Im assumning its due to the "slop" in the fitment. Is the bushing pressed into the prop? I cant find a part number for it, I can only find a # for the whole prop.. Also in doing a little research I found 2 different part #'s for the prop? a 9 x 9 and a 9x10. what does this refer to, and how do i know which one I may need? Thank You in advance.

 

[jestor68]

Re: Prop Question - 1970 Evinrude #25002C, shear pin

The numbers refer to diameter X pitch(in inches). How big is the boat you are using the 25 on?

Unless a good prop shop can replace the bushing in your prop, a new one is not too expensive($83?).

Unless your boat is very light weight, I would think that the 9 X 9 size might work. Remove your old prop and look for some numbers stamped on it somewhere.

 

[steelespike]

Re: Prop Question - 1970 Evinrude #25002C, shear pin

Is it the slop in the prop or is the pin loose in the shaft?
Is the motor idle good and low, 700 rpm?
Here's a cob job repair idea.After inserting the pin in the shaft wrap it with aluminum foil to fill the space till it seems snug in the prop.
Maybe thin copper foil; perhaps from the hobby shop.
The best solution is a new prop.try to gert it to work enough so you can do a test run and get the wot rpm and gps speed.
Tell us about the boat and load and the present prop size.Usually near the base of the blades or on the hub.
Something like a Tinytach for the rpm.
Pitch size is the important number. Size is written diameter X pitch. The lower pitch will be more powerful and may be needed if you run heavy. Your present prop size,wot rpm and speed will help tell if your present setup works.
I just realized the pin goes through after the prop is positioned.
The pin is a drive pin not a shear pin.The hub is designed to slip if prop strikes something.A stainless
drive pin should be stronger and may even be intended.

 

[jay_merrill]

Re: Prop Question - 1970 Evinrude #25002C, shear pin

Good point by SS - you have a drive pin, not a shear pin.

This brings me to my next thought, namely a question as to whether or not you are using a correct OMC drive pin for your motor. The system that your motor/prop uses, relies on the hub in the prop letting loose, when you strike something. With that in mind, I have to wondering why the pins that you are using keep breaking.