1960 Johnson 40 hp wont's stay running

[willinokc]

At it again trying to get this motor running right. Rebuilt ignition, new plug wires, checked gap on points, rebuilt carb, replaced carb in case I didn't rebuild right, new water pump, new hoses, new head gasket. Runs better but won't stay running, after about 5 seconds it cuts out. Happens after it warms up. Not giving up but man am I getting worn out. Not used to working on engines so I've learned a lot but have the feeling I gotta be missing something simple.

Short video of it running at this link.

http://www.youtube.com/watch?v=gwaIbCqSYm0

Any help appreciated.

 

[bktheking]

Re: 1960 Johnson 40 hp wont's stay running

Disconnect the harness to the motor and pull start it, this will rule out an ignition switch issue. Doesnt sound like fuel as it starts instantly, sounds like it shorting out and killing the ignition. If that doesn't work make sure you have spark on both and dsiconnect any pressure switches if it has then connected, usually black wires.

 

[EvlScooter420]

Re: 1960 Johnson 40 hp wont's stay running

Pull the flywheel off and test the stator. and or copper coils

 

[bktheking]

Re: 1960 Johnson 40 hp wont's stay running

No stator on these motors that I know of, point and condensors and 2 coils.

 

[willinokc]

Re: 1960 Johnson 40 hp wont's stay running

Do have spark on both cylinders, checked that. Don't know of any pressure switches on this model. There are black wires, one comes off of each point assembly which, ground the points out if engaged. One goes to a vacuum switch for overrun, one goes to the ignition switch and completes the circuit when you turn off the key to kill the motor. I've checked both wires for breaks and can't find any.

 

[EvlScooter420]

Re: 1960 Johnson 40 hp wont's stay running

really? See i learn new stuff too lol just a suggestion. will you post back on evinrude 14 hp

 

[willinokc]

Re: 1960 Johnson 40 hp wont's stay running

Correct, no stator. New coils when I rebuilt ignition but I guess it's possible one is bad.

 

[bktheking]

Re: 1960 Johnson 40 hp wont's stay running

It would still run on one cylinder, something sounds like it's taking out spark all together, in all likelyhood a bad ignition switch.

 

[bktheking]

Re: 1960 Johnson 40 hp wont's stay running

Do have spark on both cylinders, checked that. Don't know of any pressure switches on this model. There are black wires, one comes off of each point assembly which, ground the points out if engaged. One goes to a vacuum switch for overrun, one goes to the ignition switch and completes the circuit when you turn off the key to kill the motor. I've checked both wires for breaks and can't find any.

The vaccuum switch is what I was referring to, pressure switch.... That will only kill one cylinder to prevent run away.So spark of both cylinders, disconnect from the harness and hand crank it.

 

[willinokc]

Re: 1960 Johnson 40 hp wont's stay running

Vacuum switch was giving me probs so I've disconnected, was killing spark on lower cylinder. With that disconnected runs on either cylinder, tested by disconnected plug wires while going from each. Video is after vacuum was disconnected.

 

[willinokc]

Re: 1960 Johnson 40 hp wont's stay running

Started to unhook the harness today and thought I would just look around and see what I could see before trying to pull start that beast. Ran fine for a bit and then started acting up again so I went back to basics and pumped the primer bulb from the gas tank. Low and behold if I did that it stopped cutting out. With this in mind I swapped the fuel pump with a spare I had. Bingo, stopped cutting out. Pulled the old pump apart and the diaphragm had a 1/2 inch rip. Go figure.

 

[bktheking]

Re: 1960 Johnson 40 hp wont's stay running

Started to unhook the harness today and thought I would just look around and see what I could see before trying to pull start that beast. Ran fine for a bit and then started acting up again so I went back to basics and pumped the primer bulb from the gas tank. Low and behold if I did that it stopped cutting out. With this in mind I swapped the fuel pump with a spare I had. Bingo, stopped cutting out. Pulled the old pump apart and the diaphragm had a 1/2 inch rip. Go figure.

That is so bizarre, makes no sense as it would start without priming unless you are a really good video editor, I didn't see you touch the bulb.

 

[willinokc]

Re: 1960 Johnson 40 hp wont's stay running

I know, it's weird. It would start fine, run for a bit but after it warmed up it would cut out, just like in the video. When it started doing that I happened to be at the back so I pumped the primer just to see. It stopped cutting out. My guess is when it was cold the choke was getting it enough fuel. When it warmed up and the choke stopped, it was getting some fuel pressure but not enough. Just guessing here though.

The rip was along the lip of the bowl/indention in the fuel pump so I guess it was working to an extent.

 

[bktheking]

Re: 1960 Johnson 40 hp wont's stay running

Cool, well its fixed, now go have a beer