68 Johnson 9.5 HP Engine & Prop Trouble

Tye2791

Cadet
Joined
Nov 9, 2005
Messages
6
I recently took my boat out and had the following problems. The motor would start easily, but would only run for a few seconds (10 at most). It seemed like it wasn't getting enough gas and then it would run like it was getting plenty and then back to like it wasn't getting enough. This went back and forth each time until I gave up. What I know about boat motors could fit in a thimble, but I am willing to learn. All I could figure was that the fuel line was clogged, but this didn't seem to be the problem. Anyway, when the engine would run, it sheared two pins during the process. I recently bought a new prop and pins after getting some great help here so the prop should be fine. When I examine the shaft? (the thing the shear pins slide through and actually turns the prop), it appears now to be worn around the edges and the sheared pin is stuck in it. I know I have more than one problem here and would like to try and fix it myself if possible. Any advice is greatly appreciated.
 

BTF112989

Petty Officer 3rd Class
Joined
Dec 30, 2005
Messages
94
Re: 68 Johnson 9.5 HP Engine & Prop Trouble

On my first guess I would think the fuel pump is shot. Try pumping the bulb while it is running and if it keeps running while you are pumping the bulb constantly then it is probably the fuel pump. I have a 1969 Johnson 9.5 hp. Mine likes to bend the shear pins while they are in place so it is often difficult for me to get them out. I usually have to use a pair of pliers to get the pin out.
 

JB

Honorary Moderator Emeritus
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Mar 25, 2001
Messages
45,907
Re: 68 Johnson 9.5 HP Engine & Prop Trouble

Johnson Troubles
 

OBJ

Supreme Mariner
Joined
Dec 27, 2002
Messages
10,161
Re: 68 Johnson 9.5 HP Engine & Prop Trouble

When you go bending shear pins and wallowing out the shear pin holes, that means the engine is idling way to high. Tye...can we get some history? Is this engine new to you or did the problem just crop up?<br /><br />If the engine is new to you, has it been setting a long time before you got it?<br /><br />Reason for the questions is that it sounds like the carb is pretty much gummed up.....could be wrong here....but that's the way it sounds.<br /><br />Post back with any info or history on the engine you can give.....thanks! :)
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: 68 Johnson 9.5 HP Engine & Prop Trouble

Ditto on the elongated shear pin hole. The rocking or back and forth motion of the prop causes the pin to be slammed one direction then the other until it finally bends and breaks.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 68 Johnson 9.5 HP Engine & Prop Trouble

i agree with OBJ. in 40 years i've only broke 2 shear pins.
 

Tye2791

Cadet
Joined
Nov 9, 2005
Messages
6
Re: 68 Johnson 9.5 HP Engine & Prop Trouble

I tried pumping the primer while it was running and it didn't seem to make a difference. How can I tell if the fuel pump is shot? <br />I've had the boat for a few years, but only get out 5-6 times a year. I havn't had this problem with it until now. I took it out in November and didn't have these troubles. It may be the idle speed is set too high. I re-read the manual after I posted the first time and it does seem like it ran pretty high. How could I tell if it is the carberator being gummed up? Can I do anything about it?
 
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