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Why is bearing housing on 9.9 notched?

S

Stevetheno

New member
I have 1985 9.9hp 2 stroke. I now know that it has drive and gear case design I. Its been patiently stored in my garage for 20 years. Decided to go thru it this winter and get it ready to use again. Unit is low hours and in excellent condition. Opened up gear case to inspect. All looks good except I am puzzled by one feature. The bearing housing is manufactured with notches on the end that the prop thrust washer butts up to. The thrust washer is grooved on inside to align with shaft grooves. The thrust washer collar is also notched and the notch pattern matches the bearing housing. If the thrust washer was to be installed one way, the notches in the thrust washer collar would fit between the notches in the bearing housing. This would lock the thrust washer to the bearing housing and effectively prevent the prop shaft (or any part of the drive train for that matter) from turning. If the thrust washer is installed the other way, than a neck on the washer keeps the collar from contacting the bearing housing and the prop shaft can rotate freely.

My question is if the thrust washer collar is not supposed to lock to the bearing housing, why do the notches exist?

Also, when I said the gear case was in excellent condition, that wasnt quite true. One of the “ears” between the notches in the bearing housing has been sheared off. And, the “ears” on the thrust washer collar are worn and nicked. It appears that the washer collar has contacted the bearing housing under some conditions in past operations. But, I am not sure how to prevent this. There does not appear to be any spacers or washers missing from the shaft-prop assembly.

Any insights appreciated.
 
???-----That thrust washer was designed to be the tool to remove the bearing carrier.-----Damage is there because someone did not realize that there is a left hand thread.
 
racerone said:
???-----That thrust washer was designed to be the tool to remove the bearing carrier.-----Damage is there because someone did not realize that there is a left hand thread.
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interesting. Thanks! That thrust washer is no longer available. Do you know if I can replace it with a later year (like 1986) thrust washer that would not have the notches? The bearing housing is available, but same question; could it be repalced with a later year model that would not have the notches? Thanks!
 
Stevetheno said:
interesting. Thanks! That thrust washer is no longer available. Do you know if I can replace it with a later year (like 1986) thrust washer that would not have the notches? The bearing housing is available, but same question; could it be repalced with a later year model that would not have the notches? Thanks!
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What year is that motor ?I do not believe there was a 9.9 in 1985 just a 9.8 and they are not the same. Or is this a Mariner 9.9 which would be a Yamaha built motor? My guess is your motor is a later Mercury built. The notches on the thrust washer face out towards the prop. They are only flipped over to remove the bearing carrier. There should be a metal cap that goes over the notches when it is not being used as a tool.
 
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flyingscott said:
What year is that motor ?I do not believe there was a 9.9 in 1985 just a 9.8 and they are not the same. Or is this a Mariner 9.9 which would be a Yamaha built motor? My guess is your motor is a later Mercury built. The notches on the thrust washer face out towards the prop. They are only flipped over to remove the bearing carrier. There should be a metal cap that goes over the notches when it is not being used as a tool.
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Thanks. Everything on it says Mercury. The serial number is 0A947038. I couldn’t find any dates, except on the electrical ignition switch box. Its stamped 1985, but I guess it could be a 1985 part on a later model unit? Also, the notched thrust washer arrangement seemed to match exploded view diagrams for the earlier versions of the unit.

I have not been able to locate any caps, and none was on it. Possible to use a later year thrust washer version without notches?

Thanks
 
Sure----A later year thrust washer will fit.----Support your local friendly shop that can help you with this puzzle.-----My wild guess is an 86 / 87 model.----Perhaps even an 8 HP with 9.9 cowling.
 
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