Johnson 10hp Seahorse: issues with fully going into gear

[tredragon]

Today on the lake we had our boat out for just the second time since I bought it. We rode around for most of the day with no problems, but upon returning to the dock, all of a sudden the RPMs went up and yet we slowed WAY down. I thought maybe something in the lower unit had stripped out. We could move at about 1/3 throttle, but any more and we were just revving up the engine with no resulting propulsion.

When I got home I noticed that the shifter linkage wouldn't fully go into FWD. I pulled the prop and found quite a bit of fishing line wrapped around the shaft, which I removed. Then I noticed that if you put it in FWD and spun the prop a bit, then it wouldn't go fully into REV. If you put it in REV and spun the prop a bit, now it wouldn't fully go into FWD. It would go about half the way (the shifter linkage).

If I then put it into neutral and spun the prop around and tried to shift it, I could eventually get it to go all the way into gear, but rarely would it go from REV w/spinning prop to fully into FWD, or vice versa.

Any ideas what might be the problem?

 

[Daviet]

Re: Johnson 10hp Seahorse: issues with fully going into gear

If you are trying to shift the engine without the engine running you have to rotate the prop by hand to let the cluth dog and gears mesh and align themselves to go into gear completely.
It sounds like your problem, RPM going up and boat slowing down, sounds like a classic case of a spun prop hub.
Do you know how to check for a spun hub?

 

[tredragon]

Re: Johnson 10hp Seahorse: issues with fully going into gear

If you are trying to shift the engine without the engine running you have to rotate the prop by hand to let the cluth dog and gears mesh and align themselves to go into gear completely.
It sounds like your problem, RPM going up and boat slowing down, sounds like a classic case of a spun prop hub.
Do you know how to check for a spun hub?

Not exactly. I started by pulling the prop off but then realized there was a lot more that I would have to pull in order to check any more gears. Please let me know how to check for spun hub. I thought that might be the case but wasn't sure.

 

[tredragon]

Re: Johnson 10hp Seahorse: issues with fully going into gear

I don't hear any strange sounds when in either gear spinning the prop but how else can I check for spun hub?

 

[Daviet]

Re: Johnson 10hp Seahorse: issues with fully going into gear

Your prop should have a brass hub inside of a rubber bushing. Remove the prop and scribe a line across the hub onto the prop. Install the prop and run the engine until it acts up, remove the prop and see if the scribe marks still line up, if the marks don't match up you have a spun hub and will need to get the prop rehubed.

 

[tredragon]

Re: Johnson 10hp Seahorse: issues with fully going into gear

I'm pretty sure it's spun. I'd buy another one just to have a spare, even if it's not spun. I can find them new, but can't find anything used. I guess if I knew what other models used this prop it might be easier to find a used one. Seems a 8.25" 8 pitch non-thru hub standard spin prop would work...now, which other models besides my Johnson used this?

 

[Daviet]

Re: Johnson 10hp Seahorse: issues with fully going into gear

I am sure there is a number of engines that used that prop depending on boat size. Look in the "Top Secret File", there is a list of salvage yards there. Find some close to you and give them a call.

 

[kfa4303]

Re: Johnson 10hp Seahorse: issues with fully going into gear

HI tredragon. Here is a handy link for your little 10hp.

Johnson

 

[HighTrim]

Re: Johnson 10hp Seahorse: issues with fully going into gear

What year motor do you have? What is the model number? Shoot me a PM.

 

[tredragon]

Re: Johnson 10hp Seahorse: issues with fully going into gear

Thanks guys. Chris, I sent you a PM.

Still looking for a used prop, which may be hard (and is it more likely to spin again or is that just an unavoidable thing from getting caught on something?).