1989 johnson 100 gt

robyn e

Cadet
Joined
Jul 26, 2013
Messages
6
In the top right corner of the motor isa little thing that looks like a compass nedle. Anyone know what it is? The motor has a schraeder valve in it.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 1989 johnson 100 gt

(Fuel Primer Solenoid Function)
(J. Reeves)

The RED lever...... The normal operating/running position is to have that red lever positioned over top of the solenoid and aimed at the other end of the solenoid, gently turned to its stop. This is the normal/automatic mode position. Pushing the key in opens the valve within the solenoid allowing fuel to pass thru it in order to prime and start the engine. Looking upon this solenoid as a electric choke results in a better understanding of it.

Having that red lever turned in the opposite direction, facing away from the solenoid, allows fuel to flow thru it to the crankcase area. One would only turn the red lever to this position in a case where the battery might go dead and the engine had to be started via the rope pull method. Look upon putting the red lever in this position as moving a choke lever on a choke equipped engine to the full closed position. Either one would supply fuel to the crankcase/engine for starting purposes BUT if left in that position while running would flood the engine.

The later model primer solenoids are equipped with a schrader valve, used for attaching a pressurized can of fogging oil etc, available at your local dealership with complete instructions.

Pumping the fuel primer bulb up hard fills the carburetor float chambers of course, but that process also applies fuel pressure to the primer solenoid.

The two small hoses leading from the primer solenoid branch off via tees to each fuel manifold section that would feed fuel to the individual cylinders.

Pushing the key in activates the primer solenoid to allow fuel to flow thru it to the intake manifold passageways. Cranking the engine over causes the fuel pump to engage which in turn sends fuel pulses to the primer solenoid via the 3/8" fuel hose.

Some engines incorporates the "Fast Start" feature which automatically advances the spark electronically so no advance of the throttle is required for starting.
Engines that do not have the "Fast Start" feature will be required to have the throttle advanced slightly.

Starting procedure: pump fuel bulb up hard, crank engine and push the key in at the same time. When the engine fires/starts, release the key so that it falls back to the run position.

Bottom line..... Look upon the primer solenoid as an electric choke.
 

robyn e

Cadet
Joined
Jul 26, 2013
Messages
6
Re: 1989 johnson 100 gt

After priming motor starting and taking off the carberator runs dry and quits. Any help there?
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 1989 johnson 100 gt

After priming motor starting and taking off the carberator runs dry and quits. Any help there?

Not sure of what that means. I'll need a better explanation of what is happening. If you're saying that the engine starts but then runs out of fuel and stops running, that could be a fuel leak somewhere between the pump and the fuel supply, a faulty fuel pump, something of that nature.
 

robyn e

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Joined
Jul 26, 2013
Messages
6
Re: 1989 johnson 100 gt

As long as someone is constantly priming the pump it runs beautifully, but when you stop it cuts out. Any ideas? It is an oil injected motor and was told would be 500 to replace fuel pump or maybe put on a different fuel pump and mix oil myself. Has anyone out there had this problem and can offer cheaper alternatives or tell me if it may not need replacing?
 

Fleetwin

Lieutenant Junior Grade
Joined
Nov 23, 2011
Messages
1,141
Re: 1989 johnson 100 gt

As long as someone is constantly priming the pump it runs beautifully,

That's your key that the fuel side of the fuel/oil pump is ma;lfunctioning. Some of them you can rebuild. Otherwise, replace it or install an old style NON oil injecting pump.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1989 johnson 100 gt

You may be referring to the timing pointer. It's uses to verify/set the ignition timing with a timing light.
 
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