1977 35hp 35702h Evinrude

[stone88]

Hi all

Struck a rock causing the lower crank bearing and central sleeve bearing to both crap their pants.

Sleeve bearing has left deep pits on the crank bearing surface from one of the needles breaking in two.

Questions i have so far, which are really just options going forward:

1. Can welding add material to the crankshaft and a lathe take it back to perfect smooth diameter?
2. The part number of the 35hp crank is 321939 but i often see the 25hp crank 321747 being sold as the 35, are they compatible in the same crank case?

Bought the motor for cheap so would be economical (and fun!) to do.. there is a relatively cheap crank out there with both bearings..

thanks in advance.

 

[racerone]

Crankshaft can not be repaired in the home workshop.--------Consider that welding usually bends a shaft.---And bearing surfaced are " hardened " as well.

 

[F_R]

Really hard to believe that hitting a rock caused that damage. Not that it matters at this point. Toast is toast.

 

[stone88]

Thanks chaps

And fair enough - i have no experience with either boating or outboard motors.. And the motor was in a pretty rotten condition on teardown.. thermostat was stuck open from a small shell fragment lodged in the spring, which resulted in salt and scale build up that eventually distorted the water jacket gasket.

Just a gut feeling that after 52 years of duty the rock strike could have been the final nail in the coffin. ..then again i read that a motor of my year would be fine on a 1:100 mix and it was shorty after both of those nails that she jammed up.

Perhaps the metal fragments from one bearing failure caused the other to go

 

[racerone]

No , no ---That motor runs on 50:1 mix , nothing else.

 

[jimmbo]

I think you are aging your motor a few yrs too many, a 77 model would be about about 42 - 43 yrs old, depending how you count the Model Year release date.

 

[Crosbyman]

try free classified ads on AOMCI site maybe somebody can help out …

I got rid of a Merc 20 years ago because it punched a 1'' hole on the side of the power head….

today… knowing better... I would look for parts and at least try to fix it

 

[racerone]

To answer question # 2 there were changes made to the crankshaft splines in the late 1970's on the 25 and 35 HP models.-----And sellers are not always sure of what they are selling !-----And I doubt that the rocks had anything to do with this failure.

 

[stone88]

Ok great thanks gents. Yep added a decade on to the age somehow.

I found this: https://greenbayprop.com/321939-evinrude-johnson-outboard-crankshaft-25-35-hp-1977-5150 It's listed as having good bearing surfaces. from fresh water use, and comes with some what of a return policy but if is as it states in the listing should be fairly straight forward. Shipping to NZ is a steep though!

E-mailing them revealed it comes with the needles, retainers and metal sleeve of the centre bearing and the lower bearing.


Would the 100:1 mix cause this kind of damage? Or could it be dirty fuel? The fuel tank is an old metal thing. I poured out the old fuel but didn't put too much time into getting every last drop..

 

[F_R]

Can't say I've ever personally witnessed one damaged by 100:1. But as I understand it, the chief problem was rust of bearings during long storage problems. With that I mind, I suppose it might have caused your failure.

Another thought, that model was plagued by overheating in certain areas (weedy lakes). And overheating can cause gasket leaks and water intrusion into the crankcase----a bearing killer for sure.