Help Finding Prop Evinrude 50

Cherokee Lake

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Aug 30, 2015
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I recently acquired an E50BELCTA. A 1983 50hp Evinrude, seems a good motor, starts 2nd or 3rd try, runs strong.

Needed a new prop, so I ordered a Solas Amita and a matching BRP hardware kit from here on iboats using the prop selector guide.

Shipping was extraordinarily fast, I received what I ordered in less than 48 hrs.

Anyway, go to install the new prop and hardware kit, I slide the new thrust washer on, and it doesn't slide all the way on the shaft, it's too small.

Trying the new prop with the old thrust washer, the prop doesn't mate up, the old thrust washer is too large where it mates up with the new prop.

Of course new prop and new thrust washer mate up, as does old/old.

The hub on the new prop is a smaller diameter than the hub on the old prop.

Doing some research, I find the the OEM thrust washer for an E50BELCTA is p/n 320305.

The thrust washer currently on the motor is a p/n 318841--clearly stamped on the side with an "M" inside an outline following it.

Doing further research, I find a 318841 thrust washer fits a 90hp Johnson/Evinrude, among others I'm sure.

What gives? And how do I find a prop to fit the current thrust washer and my 50hp motor, as a prop for a 90 hp isn't right.

BTW, the old prop is all crudded up, the best I could come up with is it measures 11 ?/? w/a 17 pitch.

The new Solas Amita is a 12" x17 pitch with a J/E BRP hardware kit 40-75H.

I am thankful in advance for any help I can get, and forgive a newbie a long rambling post and any dumb questions.
 

Sea Rider

Supreme Mariner
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Sep 20, 2008
Messages
12,345
Welcome to Iboats,

Should have checked which was the current factory delivered prop sent with that 50 HP, check if other pitches are available and go from there selecting other brand props. Sometimes you have to deal with prop hardware incompatibility which original props don't have.

What's the condition of the old prop as to wot test it and check if inside safe wot range.

Happy Boating
 
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steelespike

Supreme Mariner
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Apr 26, 2002
Messages
19,069
When you say the washer won't go all the way on the shaft are you sure the washer is ok not damaged or bent
Perhaps a defect that could be removed with a little sand paper. No crud on the shaft?
I wonder if it is a V4 shaft or gear case?
​ Maybe prop sales will send you another washer.
 

Cherokee Lake

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Aug 30, 2015
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5
Sea & steele, thanks for the replies.

Got off work early enough to be able to make it to a West Marine store.

That didn't solve any problems; and I'm glad it didn't, I didn't like the looks of their props compared to the Solas.

I was able to get home early enough to take some pics to better illustrate what is going on.

002.JPG

Here's the 2 thrust washers, the current one to the left, a factory OEM equivalent on the right. As you can see steele, the new washer is a finely machined piece of metal. 006.JPG

A picture of the prop shaft.

025.JPG

Here is a pic with both thrust washers on the prop shaft. As you can see the current T/W on the left slides all the way down the shaft, the OEM equivalent, that's as far as it goes.

019.JPG

Here is a pic of the new T/W laid onto the old prop 020.JPG

And a pic of the current thrust washer with the current prop

016.JPG

A pic of the current prop, you can see why I want a new one

013.JPG

And finally, a pic of what the Evinrude is pushing.

Wish I could tell you more about it, but the Model/serial numbers don't match up with any of the Coast Guard boat manufacturers codes--that'll be the subject of a new post. It's a 15', fiberglass center console, and I can safely say it was made in '85

I expect steele is correct in saying that this may be the shaft from a V-4 as a Google search for for the p/n on the current thrust washer found an ebay ad for the washer removed from a 90hp Johnson.

So, looking for a prop to match the shaft and thrust washer. It seems to be easier to find a thrust washer to fit a certain prop, than it is to find a prop that fits a certain thrust washer.

Hope the pics better illustrate the problems, and again thanks for any help.
 

steelespike

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Apr 26, 2002
Messages
19,069
What is the diameter of the gear case?Does the new prop fit the shaft but for the washer problem? Does it fit the gear case? but for the lack of a washer.
 

Cherokee Lake

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Aug 30, 2015
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steele,

When you ask for the diameter of the "gear case", do you mean the diameter of the shaft the prop slides onto?

When I get home this evening I can investigate further.
 

steelespike

Supreme Mariner
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Apr 26, 2002
Messages
19,069
If the gear case is from a V4 (I don't know if thats possible)then We need the diameter inside and outside.
And how does the prop fit the gear case and shaft disregarding the lack of a washer.
I had A revelation; We are dealing with a gear case/shaft/washer problem.Closer to a mechanical problem than only a prop
problem. Someone over in E/J repair surely will know if the shaft or gear case is the problem.Tell them I sent you Worse that will
happen we'll get yelled at.My thoughts are the old prop is maybe a OMC and fits either washer.
I desperation a Machine shop may be able to turn down the washer to fit the shaft.
 

Cherokee Lake

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Aug 30, 2015
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steele,

The new prop does not slide all the way down the prop shaft.

So, regardless of either thrust washer, it doesn't fit.

The prop shaft on the motor measures 1&1/16".

The new prop and washer are made to fit a shaft measuring 15/16".

Thing is, in the past, somebody has solved this problem, and found a prop that fits.
 

steelespike

Supreme Mariner
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Apr 26, 2002
Messages
19,069
Maybe they took a 90 hp hub and put it into a 50 hp prop.Of course the new prop may have to be an OMC prop so it fits the 90 hp washer and so you can find a hub to fit both.?You may have the hub and insert in the old prop.
 
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Cherokee Lake

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Aug 30, 2015
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Alright, had a workathon the past couple of days to make it to a 4 day weekend, but I believe I have figured the out the problem.

Managed to make it by one of the local marine stores, and was able to talk to the crusty, old marine mechanic.

Showed him the old prop, he looked at it about 2 seconds, didn't even try to make out the numbers on the hub.

"Why that's a 13 & 1/4, bout a 17 pitch"

"What motor did it come off of?"

"50 horse Evinrude I told him"

"Large Gearcase" he replied.

So, apparently somewhere along the way, the gearcase on the motor was switched out and replaced with a "large gearcase".

Used iboats prop selector tool and this time, selected one of the 50hp with the "large gearcase" choices

Lots and lots of 13 & 1/4 available, including a 17'.

I've got an RA number from iboats, I'll order me a 13 & 1/4, and hopefully next weekend I won't be so embarrassed at the launch ramp.

Thanks for sticking with me steele.
 

Sea Rider

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Sep 20, 2008
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Whichever prop you select mut be tached with a healthy tach to check if inside wot range for that engine. Blind guessing prop purchase is no good for engine..

Happy Boating
 

Watermann

Starmada Splash of the Year 2014
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Jan 12, 2013
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13,747
Whoa a 17"p prop for a 50 HP? What's the gear ratio of that large gear case? My 55 HP Johnson on a 16' aluminum boat runs a 12.5" x 13"p. I'm thinking that 17"p will take 5 minutes to get your boat on a plane and not even get 3500 RPMs. Mine originally had a 15"p prop but it was really old and didn't have the cupping or rake that the new props do so I got stuck with the 15" that would only get about 4600 RPMs.
 
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