Thrust washer 1988 Mariner 40HP

jcmaillet

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New to boating. Bought a 1988 Sylvan 820 Advantage, 20 foot, 40 HP Mariner Outboard. Previous owner used it mostly for fishing on a lake. We are using it now on the Ohio River.

Last weekend we were cruising up river back to the dock and had a suspected spun hub happen. Pulled it out of the water and took the boat to the closest shop. They confirmed it was a spun hub. Unfortunately they were zero help fixing the problem. They said the could not figure out the correct size prop replacement as my prop had no identification numbers on it, not sure if they it worn off or what, looks like it could have been the original propeller. Did some research, asked for a few recommendations, and bought a Michigan 12.25 x 9p replacement. It is slightly bigger than the original prop, and less pitch, but it seems to fit on the boat nicely.

The problem is that the shop took the prop off the boat, so I did not see how it came off. They left the prop off when I picked the boat up, and said they were going to put all the hardware back on. I didn't realize that they just left everything sitting on the back of the boat until I got home, only thing that was left was the bolt and locking pin.

I already ordered a new lock washer that goes under the bolt. My question is, is there a washer that goes in between the prop and the lower unit? It looks like the back of the old prop is worn pretty bad, so I'm not sure if it was already missing if there is suppose to be one. Seems like the new prop would grind against the lower unit.

All help is appreciated
 

GA_Boater

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What is the serial number of the motor? 1998 was a crossover year with 2 cylinders, 3 cylinders and 4 strokes coming on the scene.
 

jcmaillet

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The plate on the motor contains the following information: Mariner 40ELO 6E9 428768. Just to clarify, it is a 1988 model.
 
Joined
Oct 5, 2017
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It would depend on the prop. If the prop sits too low once it is on the prop shaft and you cannot lock it into place with the prop nut, you could purchase a thrust washer to make the prop sit higher and fill the shart better.
 

GA_Boater

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It would depend on the prop. If the prop sits too low once it is on the prop shaft and you cannot lock it into place with the prop nut, you could purchase a thrust washer to make the prop sit higher and fill the shart better.

That means you are using the wrong prop. Thrust washers are NOT meant for shimming, they are for absorbing the horizontal thrust of the prop from damaging the case.
 
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