No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 hp

[Milemaker13]

OK, so I got this used lower unit on ebay to make my little old 10 horse a long shaft in order to go fishing on the pond nearest to my house (10hp max). I got the unit the other day, finished assembling it today and fired it up but I get nothing from the prop.

Everything went together ok. What can cause this? In neutral I get no prop movement (my original lower unit would turn ever so slowly in neutral).

In forward and reverse the prop turns very slowly forward and reverse. But there is no noticeable prop RPM increase with increased engine RPM. The prop is definitely not coupled to the drive shaft.

With the engine off but shifted into gear I can turn the prop by hand and I feel some resistance in the form of very light "bumps" (broken gear teeth?).

I did check the shift linkage. In fact to rule it out I detached the shift coupler and manually moved the shift rod down as far as possible (reverse) and there is no change.

I have dropped the lower unit (my original one) several times before to change the water impeller and have never had an issue with reassembly. I have adjusted the shift handle/rod before as well.

Does anybody have any ideas what may be going on here? I wanted to jump online to post, but I am going back out to the garage now to disassemble the whole thing and see where that gets me.

My fishing trip has now turned in a camping trip. Bummer!

 

[Milemaker13]

Re: No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 h

Oh, forgot to add that the motor is pumping water as it should. This tells me that my drive shaft is in fact turning...

 

[Scurvy Knave]

Re: No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 h

Sounds like a broken shear pin.

 

[Milemaker13]

Re: No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 h

Prop shear pin? Or something else?

Looking at a part diagram I see a key at the lower end of the driveshaft. Can anyone tell me how the lower gear is attached to the driveshaft? Could this key have fallen out? How would I go about checking that?

 

[nwcove]

Re: No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 h

with any luck , its what scurvy said, but it is more than likely not that easy. id put my money on the pinion gear key , the shaft was probably lifted and the key fell out. ( could also be that someone mistakenly removed the pivot pin thinking it was a drain screw, and now the shift lever is just dangling from the shift rod)

 

[HighTrim]

Re: No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 h

If it doesnt shift manually by moving the shift rod, you are going to have to open up the skeg and see what is going on. There is a chance you have a partially sheared shear pin, so check that first, but if not, time for an inspection.

 

[Milemaker13]

Re: No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 h

Shoot. I'll bet its the pinion drive key has fallen out. When I changed the impeller, the shaft came up because the wrong key was used for the impeller (supposed to be just a pin, but this was a pin with a key head) and it was very tight on the shaft. Dang it. Why in all the instruction threads on changing the impeller has lifting the shaft never been mentioned? Why is it even possible seeing how the impeller is a routine maintenance item. Whatever.

Ok, so if that is what the issue is... How do I go about fixing it? You mentioned opening up the skeg. Simple enough to get open I think, but is the gear set then loose in my hand? And what of the seals? Am I going to need a new seal kit to close it back up?

I really appreciate the discussion. I think we are definitely on the right track here. Thank you all.

 

[HighTrim]

Re: No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 h

I believe it is something to do with the cradle connection to the dog. We will see though.

 

[Milemaker13]

Re: No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 h

That would have to do with the other screw on the outside of the case? Anyhow, can you tell me a little about opening up the gear case and more importantly, sealing it back up again. Thanks-

 

[HighTrim]

Re: No spin from the prop shaft! Bad gear box or missing something here?? 1958 10 h

You will need some spaghetti seal, and sealer. I reccomend 3M847. If all you have to do is inspect in the skeg, invert the whole motor after draining the gear oil.

Remove the skeg screws, then lift off the lower half. Dont worry, nothing will jump out at you. If you can lift the skeg half right off without removing the phillips screw, you found your problem.

Take a pic of what is going on in there and post it for us to see. Here is some info depending on how far you go with it.