1957 3 hp drive shaft question

[Baby Blue]

I have a '57 evinrude 3hp and looking for some advice on how to repair the shaft on this motor. The shaft stripped where it meets the crank. When I pull the lower unit off the shaft that drives the prop is stripped where it connects to the bottom of the engine. The shaft itself looks ok so it looks like the bottom of the crank is stripped. Would this connect to the bottom of the crank? is there any repair for this other than replacing the crank.
thanks for any advise.
BB.

 

[Daviet]

Re: 1957 3 hp drive shaft question

If the crankshaft is stripped out, you are going to have to replace the crank.

 

[Baby Blue]

Re: 1957 3 hp drive shaft question

that's what I was afraid of but thanks for the reply. Do anyone know where I could buy a replacement crank? is there aftermarket parts available so do I have to find another one for parts?
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[Daviet]

Re: 1957 3 hp drive shaft question

For that year engine, I would bet that you are going to have to start searching the salvage yards. Is the engine worth rebuilding?

 

[asdasc]

Re: 1957 3 hp drive shaft question

That seems like an odd problem to have. Are you sure that is the issue?

What led you to this conclusion? Are you sure that you have inserted it fully into the crank? I don't know this model well so maybe this is a common issue, but I haven't seen any mention of it on here before.

 

[Baby Blue]

Re: 1957 3 hp drive shaft question

This was an outboard my grandfather gave me years ago so I'd really like to get it going again for my son when he's old enough. Motor itself runs very well.
When this happened I was running it on the boat and the engine suddenly raced high rpm but wasn't turning the prop. It acted like it was in neutral but that motor is always in drive (no neutral or reverve). You spin the motor around to work reverse.
Shear pin is fine but for some reason is stripped out where the shaft seats in the crank. Didn't hit anything when it happened and I was in 20' of water so didn't hit bottom. I thought it was a strange thing to break myself. Being 16 at the time I brought it home and cut some pieces of wire to shim in the bottom of the crank and pushed the shaft back in . It worked for a few hours but spun loose again. Obviously that wasn't a good way to try and fix it but I didn't know any better at the time.
I'm going to open it up this week after years of it sitting and take a look again.
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[R.Johnson]

Re: 1957 3 hp drive shaft question

When upper drive shft spline's wear out. the cause is gererally a bent exhaust housing.. One a small 3 HP, this most often caused by backing into something. Either while backing the boat in the water, or while backing the trailer. Are there any peice's bent, or broke on the gearcase?

 

[F_R]

Re: 1957 3 hp drive shaft question

When upper drive shft spline's wear out. the cause is gererally a bent exhaust housing.. One a small 3 HP, this most often caused by backing into something. Either while backing the boat in the water, or while backing the trailer. Are there any peice's bent, or broke on the gearcase?

Aw heck, I've seen lots of them with that same problem. It comes from leaving that ten-cent o-ring out---the one that keeps water out of the splines. Without the o-ring, water gets in there and rusts the splines out of the steel crank. It will happen in just a couple of years if used in salt water---may take a few more in fresh. Let's see, 2009 - 1957 = 52 years.

 

[Baby Blue]

Re: 1957 3 hp drive shaft question

I got it running this evening after a bit cleaning of the carb, plugs, etc. It's been sitting for 20 years and took some work to get it going again. Once warmed up she ran great and after about a half hour it "spun" loose up in the crank and made a whining sound. Again there is only forward on this engine so it's always spinning the prop (no neutral or reverse).
I shut it down and turned the prop by hand. I then put my ear to the crank area and could hear it spinning.
Guess I'm in the market for a crank. going to be very tough to find I'm sure. If anyone knows of a source I'd sure appreciate it.
thanks again for all the info here.
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[TLL]

Re: 1957 3 hp drive shaft question

You will need a new crankshaft and a new driveshaft. I fixed one like this many years ago by removing the crankshaft and cutting/grinding a slot about 1/8" across the bottom of the crankshaft. Then I found an appropriate needle bearing, fit it to the slot, drilled a hole in the driveshaft and inserted the bearing (press fit). The needle bearing then will fit into the slot of the crankshaft and engage with the driveshaft. This motor has been runing for 20 years now. Doing the job was easy, but figuring out how deep to grind the slot, and where to drill the hole for the bearing will give you nightmares.

 

[Baby Blue]

Re: 1957 3 hp drive shaft question

TLL.. interesting repair and good idea. I have all kinds of various parts here at work similiar to what you're talking about. We have pins here at are split down the side and can be pressed in. I'm not sure if they are hardened steel or not. Just wondering if it would be strong enough.
What was the needle bearing off of?
thanks for the advise!
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[TLL]

Re: 1957 3 hp drive shaft question

I used a needle bearing from an old connecting rod bearing. It is solid and very hard. The spring pins you have are hardened, but would not be as strong as the solid needle bearing. I suppose it would be worth a try.