Gearcase question

[neps989]

I am working on a1984 6 hp Evinrude E6RCRM that has a trashed gearset and gearcase. I may have found a used gearcase assembly that will work, however I am coming up with two different part numbers. One is 0397708 the other is 0397709. Online parts lookup indicates that 0397709 was replaced by 0439005 but gives no replacement part number for 0397708. Can anyone tell me the difference between these gearcases?
Thank you,
Rob

[fleetwin]

Rob
This is a tricky replacement indeed….I’m wondering where you came up with the part number 397709?
First off, we have to confirm what engine you have….E6RCRM describes a 1984 short shaft/15" 6hp….Keep in mind, the model number only describes the engine as it was when it came off the assembly line. In other words someone could have converted this short shaft model to a long shaft….So, you need to confirm whether or not you have a short shaft/15" or a long shaft/20" gearcase… Is there a 5" gearcase exhaust hsg extension present? If so, someone converted it to a long shaft/20" model.
The part number for a complete gearcase I have found is: 393848 which supercedes to: 439005. The part number: 397709 also supercedes to 439005, so I am guessing it is the part number for a complete gearcase from an earlier year. I don’t know what 397708 is, does not come up…
I did find reference to 397709 in the 1983 book, but I think it is a mistake, describes it as a long shaft gearcase….

So, start over for me…Tell me what the part number is for the gearcase you have found, is it a new gearcase or just a used gearcase with a described part number? Do you have a link to the seller’s posting so I can have a look?
In any event, the proper part numbers for the 1984 short shaft 6hp you described are: 393848 which supercedes to 439005, either of these will work on your engine.
There were many little changes made to these gearcases through they years, which will make important differences…You will want to make sure you can return the part in case it turns out to be the wrong one. I can only imagine you are paying a premium price for a part that is NLA: the last posted price for these new gearcases was around $900…

[frankr]

Darned if I know. marine engine gives a bunch of confusing part numbers, none of which are 377708. They give different numbers for long and short, but both supersede to 439005 at $942.16.

[neps989]

Thank you for responding, I will try my best to answer your questions.
The part number for the used gearcase as supplied to me by the seller is 397396, replaced by 395102, then replaced by 397708. The motor is supposed to be a 1987 8hp. If I go to online parts look up and go to gearcase assembly it indicates 397396 was replaced by 397708 standard shaft. If I click on more information it indicates this part 397708 was used on 1987 E8RCUD.
If I go back to the parts listing and pull up gearcase assembly 439005 and click on more information I find that part number 439005 is used on my E6RCRM and the E8RCUD from 1987.
I got my motor from the original owner and it has not been altered. It is a short shaft, no extension added. I have seen a gearcase photo from a 8hp that had the drain/ vent hole on the opposite side compared to my 6hp . If not for that, the two gearcases looked identical. Could that be the difference between the two gearcases?
I hope you can follow this mess of part numbers. I have been using marineengine.com as my source.
Thanks for your time.
Rob
Rob

[fleetwin]

OK, well the driveshafts are different on the 84 models when compared to the 87 models…Your driveshaft should have a groove near the top of the driveshaft for an oring that seals the splines. The 87 models did not have the oring groove in the driveshaft, the splines were sealed with an extra seal on the powerhead. I’m pretty sure the 87 models used the ball shift vs the clutch dog found on your 84 model as well. The ball shift unit will surely work on your engine but the innards will be totally different than found on your engine….

[neps989]

I am fortunate to have the original driveshaft that is still in good condition. The parts lists for the 84 and the 87 show the same pinion gear, and the same clutch dog part numbers. Maybe I will be able to make this work using my drive shaft? I do have a decent gear set, prop shaft, and clutch dog that i was going to use but found issues with my housing.
I guess it is time to order some parts.
I will update as soon as I can.
Thanks for all your advice.
Rob

[fleetwin]

Yes, you could use your driveshaft in the replacement gearcase. As you know, the driveshaft simply pulls out of the gearcase, so swapping it is simple. Perhaps the ball shift design was introduced in 1988. In either case, the ball shift gearcase will fit and can be used on your engine, you would just have to use a later parts books for any future internal parts replacements…
I am assssuming I am correct, your driveshaft has the groove for the oring, and the unit you are looking has no oring groove…
How much does the seller want for the used gearcase? Do you have a link so I can look at it?

[neps989]

You are correct , my driveshaft does have the oring groove. I am unable to locate a part number for the oring.
I am waiting for a final price and some pictures from seller. He claims he has two that should work. I have seen lower units from this seller listed from between $130-$175.
I will update when I get the information.
Rob

[fleetwin]

Well, that is surely a fair price if the units are OK…
I would go ahead and install a water pump kit during the gearcase replacement, use the OEM pieces which include a new oring. But sure to lube those splines properly with the moly lube included in the water pump kit…
Are these gearcases on ebay, post the link and I will have a look…Don

[neps989]

This lower unit is not on ebay. Seller has sent me pictures of the lower unit still attached to what is suppose to be a running motor. He is asking $150 for this lower unit. I am having problem loading the picture to this post. I have to leave for work and will try again later this eve.
If I decide to do this I will definitely do the water pump kit. I wasn’t sure if the o ring was included with kit.
Thanks again,
Rob

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