1958 evinrude 7.5 prop question

[merkdawg]

someone put a 3 blade prop on this motor. I know it came from the factory with a two blade prop. the three blade prop is all brass looks like the brand is CHIGAM. Is this prop worth anything?

 

[merkdawg]

Re: 1958 evinrude 7.5 prop question

someone put a 3 blade prop on this motor. I know it came from the factory with a two blade prop. the three blade prop is all brass looks like the brand is CHIGAM. Is this prop worth anything?

actually what I mean, is what would this prop fit and is there anyone looking for a prop like this?

 

[F_R]

Re: 1958 evinrude 7.5 prop question

Well obviously, it fits the 7.5hp Evinrude and Johnson motors. It would also physically fit the 5.5hp motors of similar years. And Gale-built 5hp gearshift models too. As for diameter and pitch and suitability for a particular boat, I have no idea. Everything for old motors is worth something..

P.S., could that brand be MICHIGAN? Very well known brand.

 

[HighTrim]

Re: 1958 evinrude 7.5 prop question

Clean it up some more, I think you are missing some wording as Frank stated. Should be a number with it as well.

 

[steelespike]

Re: 1958 evinrude 7.5 prop question

Just because it came with a 2 blade doesn't mean a 3 blade is wrong.
Being bronze it may be more sophisticated than the factory prop. If the diameter and pitch is correct for the motor and boat combination
it could perform better than the factory prop. Usually the size is stamped near the base of the blades.
The model number may be on the hub somewhere.If it's a Michigan you can email them and they can tell you the size,what it fits and
maybe what it cost new.They just did a speed prop for a 46-51 33 hp Evinrude Speedifour for me.

 

[Chinewalker]

Re: 1958 evinrude 7.5 prop question

Personally, I would skip the bronze prop for the old motors if you're planning on using it a lot. The heavier props put a lot of strain on the 50+ year old drivetrain, particularly when shifting. Unless you really NEED the marginally extra low end push of the three blade, I would look for an original style 2-blade aluminum prop. If it's going to be a sawhorse queen, then shine up the brass one and leave it be...

 

[HighTrim]

Re: 1958 evinrude 7.5 prop question

I do as Scott says, my show motors have brass props on them polished up. My daily workhorses use aluminum props.

Post the numbers you find and I can tell you what it is from the Michigan database.

Soak the prop in ketchup for a couple days, then wash off. Helps remove the varnish. Here is an example and what it removed from a quick coating in ketchup.

 

[merkdawg]

Re: 1958 evinrude 7.5 prop question

who knew what ketchup could do? Think I might go with chinewalkers suggestion and use the original prop. This prop seems to weigh about 5 lbs. Besides that, how much faster can this prop get me the motor is a 7.5 (ha ha)

 

[steelespike]

Re: 1958 evinrude 7.5 prop question

True its not likely to make like a 25 but might be fun to see how it does.
I believe the wear Chinewalker refers to is from shifting.Once in gear no problem.
If you did decide to try it out you could just start it in gear as we did for many years with the old straight drives
Including the Bigfour 50 hp motors.Might be fun to do a comparison.

 

[HighTrim]

Re: 1958 evinrude 7.5 prop question

Merkdawg sent me a PM with his prop id.

Was a Michigan AM415.

That makes it a 3 blade bronze prop, 8" Diameter x 8 Pitch made specifically for the Fleetwin.

Reccomended use 12-14' runabouts with 1 to 2 passengers.

 

[merkdawg]

Re: 1958 evinrude 7.5 prop question

thx. This prop has some dings on the end of the blade. What is the best way or best file to use on this prop?

 

[steelespike]

Re: 1958 evinrude 7.5 prop question

Some times if the edge as been mashed sort of mushrooming it a little; instead of filing mashed part you can carefully
flatten it with a hammer against another hammer or on a small anvil.Then smooth with a fine flat file.Trying not to remove too much.
Also if the edge is bent a little you may be able to flatten it.If a chunk is missing just try to ease the edge a little as you don't want to remove too much material. If it turns out you have some vibration occasional use may be fun but not as a regular routine.