FUBAR lower unit? 70hp Evinrude

[SoggyBritches]

Re: FUBAR lower unit? 70hp Evinrude

Heres the beginning.

Reverse gear looks great.

Forward and pinion not so good.

Heres where im stuck. How do I get the drive shaft out? Ive tugged on it a good bit.

Homade slide hammer for pulling that drive shaft bearing housing assy. Theres a weld bead on the blade end.

I believe I see what happened. The thrust bearing and shims (35-36) appear to have failed and welded to each other and eventually reduced in thickness. Causing the pinion to pull away from the drive gear just enough to overload the drive gear/pinion teeth (improper contact). ?

Thats my theory so far, and jives with the story of spontaneous failure.

Where to find gears?

 

[SoggyBritches]

Re: FUBAR lower unit? 70hp Evinrude

It looks like the forward and reverse gears are interchangable? If there wasnt so much damage, i could weld up a tooth or two and swap the ring gears. ? But the pinion is toast all the way around.

 

[boobie]

Re: FUBAR lower unit? 70hp Evinrude

The fwd and rev gears aren't interchangable. You'll have to remove the pinon gear nut, then the gear to get the drive shaft out.

 

[SoggyBritches]

Re: FUBAR lower unit? 70hp Evinrude

The fwd and rev gears aren't interchangable. You'll have to remove the pinon gear nut, then the gear to get the drive shaft out.

Ok. Thanks. After seeing so much of how this was engineered, I should of known it was the stupidest possible method.

 

[fishfeatures]

Re: FUBAR lower unit? 70hp Evinrude

never had issues with gears so am looking on with interest, sorry for your troubles SoggyBritches, hopefully it's not too bad. Good to see you tackling the issue and posting progress, keep it up .Hopefully you'll have it fixed in no time, the guys on here are a fountain of knowledge so make sure you use them if ever in doubt.

 

[SoggyBritches]

Re: FUBAR lower unit? 70hp Evinrude

never had issues with gears so am looking on with interest, sorry for your troubles SoggyBritches, hopefully it's not too bad. Good to see you tackling the issue and posting progress, keep it up .Hopefully you'll have it fixed in no time, the guys on here are a fountain of knowledge so make sure you use them if ever in doubt.

Thanks fishfeatures. As the govt says. Never waste a good crisis.

I just hope it helps someone down the road.


Ok, i believe this is the cause for failure. After looking at how the pinion gear teeth are broken, it also appears to fit this theory. There was contact. But not as much as probably should be.

According to the diagram, after removing #38 (bearing housing assy) I should have removed 2 shims, 1 thrust washer, and 1 thrust bearing.

This is all I removed. Its all there was.

 

[SoggyBritches]

Re: FUBAR lower unit? 70hp Evinrude

Ok, so I will post all my questions in one place now.

1. What is the part# for the Lower Drive shaft?

2. How do you remove the Lower Drive shaft from the Upper? (I see the little hole on the side, no set screw or pin.?)

3. What lower units are interchangable with mine? (evinrude 70hp 3cyl 70873c)

4. How do you remove the propeller shaft? (It currently is still in place with the forward gear and shift assembly). Its the only thing left I have to remove.

5. Will this 1975 65-75hp lower unit (or parts from it) interchange with my whole shebang?
1975 Johnson Evinrude 65 75HP Lower Unit Fits 73 on Up to 77 and Higher | eBay

Thanks in advance.

 

[Faztbullet]

Re: FUBAR lower unit? 70hp Evinrude

1. What is the part# for the Lower Drive shaft?

2. How do you remove the Lower Drive shaft from the Upper? (I see the little hole on the side, no set screw or pin.?)

You do not have a 2 piece driveshaft in that model,only the 2001 and up have those...the OEM is 0388795 ss to >0390946->0396728.

3. What lower units are interchangable with mine? (evinrude 70hp 3cyl 70873c)

Any 3 cylinder "big gearcase" from 1978 and up that has 4 spline driveshaft..horsepowers include 60/70/75....

4. How do you remove the propeller shaft? (It currently is still in place with the forward gear and shift assembly). Its the only thing left I have to remove.

Shift it into forward, unscrew shift rod and remove and pull propshaft/forward gear and front bearing housing as a assembly....

Will this 1975 65-75hp lower unit (or parts from it) interchange with my whole shebang?
1975 Johnson Evinrude 65 75HP Lower Unit Fits 73 on Up to 77 and Higher | eBay

No as the 1975 models are a hydro mechanical shift and shift backward from your unit....

 

[ACAMS]

Re: FUBAR lower unit? 70hp Evinrude

Ok, so I will post all my questions in one place now.

5. Will this 1975 65-75hp lower unit (or parts from it) interchange with my whole shebang?
1975 Johnson Evinrude 65 75HP Lower Unit Fits 73 on Up to 77 and Higher | eBay

Thanks in advance.

I am pretty sure (96.875%) that the lower unit pictured will work ...... look at the pic and see if it looks the same!

look at the shift rod!

I don't think they changed until 1979, because I have several of those motors.

 

[SoggyBritches]

Re: FUBAR lower unit? 70hp Evinrude

Thank you Faztbullet and ACAMS for your replys.

Looking at my driveshaft, its definately a 2 piece. However, it may be permanently press fitted. And not marketed as a 2 piece. ? There is no part # on it.

Also, which direction is forward shift? In or out. I have tried every way and in between. And that prop shaft still wont come out. If I shift out, and pull on the prop shaft, the prop shaft pops out only out about a 1/2" and stops, and the clutch/shift shaft is now clicked in the IN position.
So naturally, if I shift IN, and pull on the prop shaft, nothing also. The forward ring gear appears to just sit still, while the prop shaft lugs in and out.

I already ordered that 75' lower unit that I linked to. The seller told me it would work as a replacement for mine. Even though taking that with a grain of salt, I figured the chance was worth the nice price considering im not finding much else.

Even if that 75' shifts backwards, so long as it fits, dont bother me none. Thats when you just call it a 'special edition'.

 

[Faztbullet]

Re: FUBAR lower unit? 70hp Evinrude

I don't think they changed until 1979, because I have several of those motors.

About 1977 is change....

Even if that 75' shifts backwards, so long as it fits, dont bother me none. Thats when you just call it a 'special edition'.

You will need all the 1975 bellcrank levers,linkage and shift lever to make it shift as throws/lengths are different

 

[SoggyBritches]

Re: FUBAR lower unit? 70hp Evinrude

You will need all the 1975 bellcrank levers,linkage and shift lever to make it shift as throws/lengths are different

Ok. thanks. I hope atleast the internals (drive shaft, gears) are the same.? I'd just use them in mine. If I could get it apart completely.

I got the prop shaft out finally. Just had to wiggle, tug, and oscillate it around for about 10min. Came out little by little.