Lower unit, 6 HP Evinrude, R&R question.

[Tim Frank]

Due to incompetence (mine unfortunately so nobody else to blame), I have to R&R the lower unit on this little gem.
I have a problem with availability of the roll pin that supports the Driveshaft-crankshaft seals etc.
It's available, but will take some time to arrive.

The local dealer says to bring in the bent one and they can probably match up one a bit longer and i can cut or grind it to length.
Does anyone have any idea what the length tolerance would be? Intuitively they would have used a stock pin from somewhere, so i could probably get a match from a bearing and equipment shop, but if tolerance is not critical, grinding to size would work.

Also,how can you be sure that all those parts are still "aligned and stacked" as they should be and that nothing has moved?

 

[racerone]

The pin should stick out about 3/16" on both sides.----Take pride in the motor and it is a very good motor.----Your best bet is to remove the powerhead and inspect that seal assembly.-----Install the lower unit and then the powerhead.-----That upper seal is critical in keeping water out of the engine.----Just takes 7 screws and a few other parts to remove powerhead.----Remove low speed needle and choke knob..

 

[F_R]

The roll pin is stainless steel. You probably won't find one in most hardware stores. A steel one is prone to rust, seal falls apart, water gets into powerhead, water rusts the bearings, rusty bearings break a connecting rod, rod punches through side of crankcase. Clear??

 

[Tim Frank]

Thanks for the responses.
As it turns out, I am going to go the really careful route and take the powerhead off so I can actually verify condition of the seal and associated parts.
Dealer had to order the gasket, so I ordered the pin as well.

FR, I'd have only used a SS pin; the issue was simply how tight the tolerance is. If +/- 1/64 would be OK, I'd have ground it. If by some chance it was +/- 0.004", I'd probably have passed. I could see myself with a stack of pins that i'd managed to grind a few thou too short.

As we all know, once it is too short, you can grind it as many times as you want afterwards....and it will still be too short.

 

[Tim Frank]

OK. Power head is off.
The "package" consists of 6 parts....a few questions.
Would appreciate some advice.
From the top:
1) a gasket 303355 in bad shape, will change it.
2) plate....303356...seems pristine...it's $50- for a new one....unless anyone has a convincing argument against i will reuse it.
3) o-ring...303347. MIA, so no-brainer. Will replace.
4) Lower bearing seal. 303357....seems OK, but OEM manual says to replace...it's $30-, so if anyone has a really compelling case to reuse the old one I'll listen, but probably go with the manual.
5) Spring....303357. Any reason to spend $15- on a new one? It seems fine.
6) Bottom spring washer. This has indents from the support roll pin, but seems OK otherwise. Another $20-. Opinions on reusing?

 

[racerone]

If parts are good you re-use them.--Dimples on the lower washer are there to drive the assemly via the pin.-----Plate 303356 is stationary.---That plate can be re-furbished with some 600 paper and a piece of flat glass.

 

[F_R]

OK, length of the pin is not critical. It needs to be long enough to extend out past the dimples on the spring retainer. But not too long to go down through the slot in the housing if you ever want to drop the lower unit again. IF it has such a slot. Depends on what year it is.

I agree, 303347 o-ring and 303355 gasket should always be replaced. No need to replace all that other stuff if it is in good condition. And glue the 303355 gasket to the plate so the plate doesn't spin. Any suitable gasket stickum to glue it.

 

[Tim Frank]

Thanks guys.
FR ~ I had to order a gasket and so I also ordered the OEM pin.
Are you saying that you'd reuse 303357 ~ Lower Seal ? It looks OK....but nothing to compare it to; the o-ring should be the ultimate seal, correct?

 

[F_R]

Actually, 303357 is the spring. The carbon seal is 303391. But the answer is the same, if they aren't worn out, missing, broken, etc., sure I would re-use them. The o-ring seals the shaft(s) to the carbon seal, the wiping faces of the carbon seal against the plate completes the isolation of the shafts from the outside environment. IF water were to enter the bearing or splines, it would first have to get past the O-ring or the wiping faces of the carbon against the plate. Oil coming down from above (past the bearing) is what lubricates the wiping surfaces and splines as it runs.

 

[Tim Frank]

Got it. Thanks for the advice !