Prop bent too much to function?

schwar74

Cadet
Joined
Nov 28, 2010
Messages
17
Greetings.

Situation: I recently bought a boat with a early 70's 25 HP Johnson. I got it for a good price ($450 boat, motor, trailer, trolling motor), so didn't use it on the water prior to purchase. In my inaugural voyage to give it a test spin, some idiot (not mentioning any names :redface:) forgot to finish latching the hitch onto the ball, and it popped off while I was traveling down the highway. DOH!! Thank goodness for safety chains. Anyhoo, the trailer tipped up a couple times and bent two of the prop blades pretty severely. As a subscriber to the bigger hammer theory, I thought I'd just straighten the blades out enough to clear the lower unit housing. There was still a severe bend in the two blades.

Once it was in the water, the motor seemed to function perfectly, with one glaring exception. When I put the motor in gear and gave her some gas, all I got was lots of churning around the prop, and minimal forward/reverse thrust. With some throttle I could get slight forward progress, enough to creep away from the ramp, and then creep back.

My question: Is it possible for a prop to be so warped that it just totally cavitates and completely ceases to function? Is it possible that the prop strike damaged something else?

Once I got home, I removed the prop and started the motor and shifted in and out of gear. The prop drive shaft rotated normally, and does not appear to be bent.

Is it worth just buying a new prop? Should I scrap the motor and use the 15 hp motor that is in the corner of the garage?

Thanks.

Scott
 

ONERCBOATER

Chief Petty Officer
Joined
Oct 11, 2010
Messages
536
Re: Prop bent too much to function?

yes it is possible to damage a prop beyond functionality, yours sounds pretty bad off, iboats sells props, look under boat propellers here and you can get one, suggest you use the prop calc function and choose one, well worth it if the motor is in good shape. sorry you didnt get the chance to try it out 1st. if you need help selecting a prop let us know what type of boat hull type, material, and length, and if possible the weight of boat, that should help us get you in the right ball park.

sean
 

Biged007

Petty Officer 2nd Class
Joined
Sep 9, 2010
Messages
176
Re: Prop bent too much to function?

Sean I went one step farther, If you do the search that was mentioned you will see they run about $90.00 from Michigan Wheel. ? 2 is it worth the $$$ look at any outboard same age HP 4 sale and I think you will be shocked.
P.S. the dia. and pitch should be stamped on the prop you are replacing usually a good start considering the previous owner already did the homework.
 

schwar74

Cadet
Joined
Nov 28, 2010
Messages
17
Re: Prop bent too much to function?

Thanks guys. I'm assuming the prop was original. There's a part number on it that jibes with props for motors this size. BTW its actually a 1974.

Scott
 
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