Hit something... shifts but won't push... ('57 18 HP Johnson)

Joined
May 27, 2013
Messages
7
While I was out today I hit something submerged (the lake is way down from the last time I was out and I'm not used to being worried about the bottom). It made a loud noise (thump or clank? memory lapse...), and now I can't remember if it stopped or if I stopped it to see what had happened. When I start the motor in neutral everything seems fine. When I put it in gear--F or R--it starts working hard and smoke starts coming out of the water, but it doesn't push. Any ideas what this indicates?
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Hit something... shifts but won't push... ('57 18 HP Johnson)

Did you check the shear pin? Likely did its job and sheared.
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,129
Re: Hit something... shifts but won't push... ('57 18 HP Johnson)

I dont know that motor but look to see if the prop shaft turns while in gear but the prop doesnt, thatd indicate a broken shear pin behind prop
 
Joined
May 27, 2013
Messages
7
Re: Hit something... shifts but won't push... ('57 18 HP Johnson)

Thanks - I'm new to OBs and didn't think of what should have been my first thought. So a follow up question: the propeller is just spinning on its shaft, so I think that it is the shear pin. I have removed the cotter pin and cone-shaped nut, but now I can't get the propeller off: is there something else I'm supposed to take off? I can't find anything in the manual, but wanted to see if I'm missing something or if there was some trick (tapping it, using a puller--and what sort, etc.)

Thanks!
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,195
Re: Hit something... shifts but won't push... ('57 18 HP Johnson)

That doesn't compute. If the prop is spinning on the shaft, it certainly should be free to come off. Anyhoo, it is supposed to slide right off.
 

jrs_diesel

Chief Petty Officer
Joined
Mar 3, 2010
Messages
552
Re: Hit something... shifts but won't push... ('57 18 HP Johnson)

I had a motor once (3.5 Hp Nissan) that had the shear pin shear into 3 pieces but would not allow the prop to come off. Oddly enough, the prop worked fine and never spun at high RPM. To get the prop off took some work. I tried pulling, gentle tapping with a rubber mallet, and more pulling and this prop did not budge. I had to use wooden wedges between the prop and gearcase with the rubber mallet to get that prop off.
 

Big Jay

Petty Officer 1st Class
Joined
Aug 7, 2012
Messages
244
Re: Hit something... shifts but won't push... ('57 18 HP Johnson)

Had the same thing happen to my '58 this Sunday. Smacked a log. You may have to jiggle the prop while spinning it in Neutral to get the prop off. The pin sticks out on either side of the prop-shaft and when it shears, those pieces fall into the crevice under your prop and can hang you up. What's left is the longer piece still in the shaft, and as the shaft spins it will slide out a bit and sometimes catch the prop making you think the pin is in fact ok.

Jiggle the prop and it'll come off eventually....
 
Joined
May 27, 2013
Messages
7
Re: Hit something... shifts but won't push... ('57 18 HP Johnson)

Thanks guys - I turned the OB on its side and the pieces of the shear pin fell out and I was able to wiggle the prop off. I'm having trouble getting the piece of the pin that's still running through the shaft out; my plan is to gently tap it with a punch and ball peen hammer. Again, being brand new to this I'm paranoid about damaging something.
 

HighTrim

Supreme Mariner
Joined
Jun 21, 2007
Messages
10,486
Re: Hit something... shifts but won't push... ('57 18 HP Johnson)

Spray some penetrating oil on it, and it should punch out with ease. No worries. Carry on soldier!
 
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