'38 Neptune 1.2 hp - Seized

[garycolwill]

I recently bought what I now know is a 1938 Neptune 1A38 1.2 HP outboard, amongst other motors. This was the only one that was seized. last night I took the gas tank and head off and squirted a bunch of PB Blaster into the cylinder. This morning I came out to see if that had any effect and it did.

I'm now able to rotate the flywheel by hand and everything moves along with it. The cylinder also looks pretty darn good - it has a bit of light surface rust, but now that the piston is moving that's been cleared away and there seems to be no pitting.

However, it does take a small bit off effort to turn the motor by hand. Not much, mind you, but the motor does not turn as freely as, say, the Evinrude Elto I have have sitting next to this one on the rack.

What should be next steps? Also, does can anyone tell me what spark plug goes with this? It would be really cool if I could find a service manual or any other source of info about this motor.

Thanks!

 

[garycolwill]

I guess these Neptunes aren't very popular... :joyous:

 

[brim_buster]

http://muncie-neptuneoutboard.com/

 

[Scott Danforth]

the bearings are probably toast.

 

[garycolwill]

Scott, good idea - I think I'll just take this completely apart and check the bearings and other things. I'm a little nervous about pulling the flywheel. I was reading recently about the British Seagull (because I was told that this was one, though I now realize that's not the case) and the article was strongly suggesting that removal of the flywheel with a puller would do catastrophic damage to the motor. I wonder if that also applies here or if I can use a puller on this Neptune 1A38. Any thoughts on that?

 

[garycolwill]

Well, I took the gear box apart - no oil but lots of black grease. No signs of emulsification, and everything moved well - smooth but not loose, so I put it back together. I'll clean it up and inspect it closer then relube it later.

Next I took the carburetor and then the cylinder off and the piston, con rod seem fine - nice and smooth movement. no binding. The piston did show light scoring on it and the bottom ring was a little stuck, but both were intact and the cylinder seems ok, so not sure what that's all about. I went ahead and took the piston and con rod off as a unit (just two screws holding the big end onto the cap. The bearing surfaces seem fine, as does the crank pin (see pics). However, even with all this apart, the motor is hard to move. So, it must be the crankshaft bearings. I've got a puller putting tension on the flywheel and some PB Blaster soaking in overnight. We'll see if a little tightening on the puller and a few slams with a rubber mallet will do the trick tomorrow.

 

[garycolwill]

The PB Blaster did the trick again. The flywheel came right off with very few extra turns of the wrench on the puller, then the magneto plate lifted off and now I have the heart of the motor in my hand. And, as Scott surmised, the crank bearing is the only thing left and the crank is still very hard to move. So, what's left to do? I need to figure out how to remove the crankshaft from the body and then see what can be done, if anything, about the bearing surfaces on the shaft and on the body (block?).

Anyone know what the process is to do that?

 

[garycolwill]

I was very surprised to find that the hardest part to removed was the key that holds the flywheel to the crankshaft. There is also a collar that works like a cam lobe and actuates the points - I'm wondering how to get that off.