Problem with 1988 Johnson 150hp

I stumbled on this site trying to figure out a problem with my Johnson, looks like a great site. So here is my problem.

I have a 1988 Johnson 150, that will not stay running on it's own. To start it I pump up the primer bulb, push key in while cranking, it fires right up. After starting up if I don't keep hitting the choke it will die. Last night I tried turning the red lever on the primer solenoid, with lever in normal position it will run like explained above. Move the lever full 180 it cranks runs and does not die, same if I turn the lever 90 degrees from normal. No choking with key. I did not know what the primer solenoid did until I found this site today.
I pulled one of the carbs just to look at it, no real varnish it was actually pretty clean. I did not go into the carb just pulled the bowl to look. Does this sound like I need to go ahead and tear into the carbs, or some other problem?

Thanks

Re: Problem with Johnson 150

You're on the right track with the carbs. I'd disassemble and clean. Pay special attention to the removable jets and small passages.

BTW, it's great to see someone do the research on the forum before posting a question. There's a wealth of information in the archives, we might as well make use of it!

Re: Problem with Johnson 150

(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.