1977 9.9 evinrude gear case specs

[TonyMe]

I just got a 77 9.9hp and was looking at the lower unit and it appears like it has a leak. Grabbed the prop and it seems like it has a lot of end play (in and out). Is there a spec on how much end play there should be? On my 1990 9.9hp I have there is almost no end play at all. It shifts very good in and out of gear.

I do have an OMC service book from 1989 but there are no specs. Would a factory service manual have more detail about the gear case and have those kind of specs?


Thanks, Tony

 

[kbait]

Re: 1977 9.9 evinrude gear case specs

check out this link: OMC 9.9 - 15hp

 

[the machinist]

Re: 1977 9.9 evinrude gear case specs

I just went out & checked the 3 motors I have left from 74 to 92 one had prop forward/aft movement of just under 1/8" down to barely noticable.

My guess is that someone has left out the (brass for early motors or nylon for later) 5/16"+- thrust washer that should be under the prop nut.

 

[TonyMe]

Re: 1977 9.9 evinrude gear case specs

Yes I think that thrust washer is missing but the the prop shaft it self has a lot of in and out movment with out the prop on it. It shifts very smooth with the muffs on it but haven't put it on the boat or water yet. So I don't know if it will pop out of gear or not. I couldn't find any specs on that site but there is a lot of very good info on that site.

 

[the machinist]

Re: 1977 9.9 evinrude gear case specs

If you look at the top of the web main header, I say my articles do not replace factory manuals, but suppliment them. Therefore I don't have specifications. Don't even know if there are any as I am just a shade tree mechanic.

If your shaft itself is moving more than 1/8", I would think there is something wrong in the gearbox. And of course you have no idea of what the prevuious owner did, or had done.

I think I would drain a bit of oil out of the gearbox & check it for contamination (metal flakes, etc.). If that looks OK, then run it on the water to see if you can determine any malfuctions.

How does the shifting go? Any loss of movement in the shifting lever from Forward to Neutral & Reverse could be some indicator???

 

[TonyMe]

Re: 1977 9.9 evinrude gear case specs

I wasn't saying that the article wasn't complete (didn't know they where yours) just wanting to know if there are any specs. I have an OMC manual but it doesn't have anything in it. I have the opportunity to buy a factory service manual for it but if there are no specs then I won't buy it. This is the reason I was asking. I did drain the oil and thought it looked good. I would say the shaft moves around .040" - .050" with my eye (didn't put a indicator on it yet).

Everything seems fine with the shifting to me but never had a problem with one to know the difference. It goes in and out of gear nice and smooth on the muffs. I don't know if I will get a chance to put it on the boat this year anymore or not.

And your article is very informative and detailed. Very Nice

 

[bwkre]

Re: 1977 9.9 evinrude gear case specs

I have the service manual for the 76 9.9hp. There are no specs given for the end play. The only spec for the gearbox that is listed is in the "Clearance Chart". It reads " Propellar shaft in front gear bushing .0087 Max - .0002 Min. Ive had mine apart and do know that the bearing in the bottom of the gearbox is a cup & cone. It wouldn't take much end play in the shaft to cause problems. Looks like you might be taking it apart. There is at least 1 special tool required for assembly if you take it apart. It is for installing the cradle and pivot pin.

 

[the machinist]

Re: 1977 9.9 evinrude gear case specs

If you only have .040-.050" end thrust, I would think that is OK, my 92 has about double that. That gearbox is one that you do not want to tear into just to see what makes it tick. If the oil you drained out looks good & no settlings in the bottom & it shifts fine, you may best run it & see what it does. From my experience there is no real adjustment (or replaceable thrust washers) internally on these units as the forward thrust is governed by the front Timkin tapered roller bearing. So if there was good oil in there & that front bearing is not deteriorated (no filings) you have a unit that has a bit of slop, maybe just because of compounded tolerences.

bwkre - not understanding what the factory "Propellar shaft in front gear bushing clearence" means, except possibly lateral clearence in the bronze bushing in the forward gear to prop shaft.

 

[bwkre]

Re: 1977 9.9 evinrude gear case specs

bwkre - not understanding what the factory "Propellar shaft in front gear bushing clearence" means, except possibly lateral clearence in the bronze bushing in the forward gear to prop shaft.

I'm not sure but you are probably right. I just copied exactly as it was written. The manual makes no reference to shaft end play or how to account for it. I don't remember any shims when I resealed mine. My shifter bushing / seal was bad so I had to take it completely apart.
Your articles are a great help by the way.

 

[TonyMe]

Re: 1977 9.9 evinrude gear case specs

Ok Thanks for all the info and input. I have to pull it off to check the water pump and everything else so I will see where I have to go from there. I am going to pull the bearing and seal assembly off to change the seals. The outside seal is not in straight and the spring is almost falling off of the seal.

Another question, would it be better to use the 2 seals or the new style that you referenced in your article?

What is the purpose for the chrome water pump? Is it meant for salt water?



Thanks, Tony

 

[the machinist]

Re: 1977 9.9 evinrude gear case specs

If you are careful & use a seal puller or screw a couple of sheetmetal screws into the old seals & pliers, you should be able to pull the old seals without pulling the bearing housing. If not then, if you pull the housing, by all means check the internals. HOWEVER somethimes these housings are a BEAR to pull on older motors.

As for the seals, either, however I tend to lean for the dual back-to-back ones (they have seemed to performed well for over 20 years).

The chromed pump in the service manual is indicated for use in debris infected water.

 

[TonyMe]

Re: 1977 9.9 evinrude gear case specs

Thanks again and appreciate the help and input.

Tony