25 HP Johnson primer solenoid - I'm stumped!

rrc0

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I purchased a used 25 HP Johnson outboard (J25RLCDC) 1986 model formerly a rope start converted to electric start. Can't cold start without removing hood, turning the red primer solenoid lever to the manual position and pumping the fuel line bulb. My first step was to check the solenoid for power. Yes, the primer solenoid does click when key is on and pushed in. So I tried removing the small fuel line from the solenoid to the carb. It squirts gas 4 ft when solenoid in manual position and fuel line bulb is squeezed. However, it does NOT squirt fuel when red lever in normal position (pointing to back of solenoid) and key is turned to on position and pushed. At this point is should squirt fuel, correct? The line is pressurized and bulb is rock hard. Now to confuse me more, with engine running, when I remove the hose and push the key in it squirts fuel 4 ft. Please help. Stumped!
 

R.Johnson

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Re: 25 HP Johnson primer solenoid - I'm stumped!

With the small hose to the back of the carb removed, push the key in while cranking, and see what you get.
 

F_R

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Right, simply pushing the key in when it is not cranking does nothing. You have to push the key in while cranking.
 

rrc0

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Thanks for a prompt reply to my first post! I was not clear. I turned key to on position and pushed in. Audible click from solenoid but no gas from line. Then I pushed key while cranking the engine. Still no gas from hose (a few tiny bubbles, but no squirt). But this baffles me...with the engine running (and hose removed) a push in on the key yields a great gas squirt from the hose after a momentary pause.
 

Joe Reeves

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Dismantle the primer solenoid and clean it. Something is jamming the automatic portion of the fuel flow.
 

Dhadley

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Re: 25 HP Johnson primer solenoid - I'm stumped!

rr, you are correct. With pressure in the line the primer will squirt fuel even if the motor isn't cranking over. The solenoid is an electric valve. Activating the solenoid allows the pressure to be released. If the pressure was created by pumping the bulb the motor does not have to be turning over.

With the motor running the fuel pump is creating constant pressure (hopefully) and the primer will release fuel any time it's activated.
 

F_R

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Copied straight out of the owner's manual: Push key in and hold while cranking.
 

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rrc0

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Re: 25 HP Johnson primer solenoid - I'm stumped!

1) Primer solenoid is getting 1) fuel and 2) electrical power. It squirts gas in manual postion (red lever perpendicular to solenoid body and fuel line bulb pumped). It also squirts gas when key is pushed, engine is running and primer solenoid is in normal operating position (red lever parallel to solenoid body). However, it does NOT squirt gas to carb under the proper starting conditions (fuel line pressurized, red lever in normal position, key pushed in with or without cranking). Your ideas/suggestions are welcome!
 

Dhadley

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Re: 25 HP Johnson primer solenoid - I'm stumped!

F R, yes, it will work while the motor is cranking. But try it for yourself. Pressurize the bulb, pull a line off and either push the key in (in the On position) or move the manual lever. It is supposed to squirt, trust me. That's why the 4 step starting method works so well. That's how you get the almost instant start from a primer and not a choke. In some rare cases a starter can pull all the juice and the solenoid not work while cranking. Rare but possible.

rr, as Joe suggested, pul the top off and inspect / clean everything.
 

F_R

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Try it myself?? Heck I try it every time I start my motor. It simply will not cold-start without holding the key in while cranking. Never has since I bought the motor new.

I am not disputing that it will give a squirt as long as there is pressure in the line. What I am pointing out is that if the motor doesn't start immediately, that squirt is gone and it never will start without more priming. Holding the key in provides that additional prime.

There is more to it than the pressure in the line. There is also suction from the carb pulling fuel through the open primer.

If it ain't broke, don't fix it.
 

Dhadley

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Re: 25 HP Johnson primer solenoid - I'm stumped!

The line squirts fuel in behind the carb. The carb does not pull fuel thru the primer.

The best way I've found is to;
1- Pressure the line by squeezing the bulb.
2- Turn the key to ON but do not turn to the START position.
3- Hold the key in for an 8 count.
4- Turn the ket to START.

It should fire up almost instantly. Yes, you may have to add more fuel by holding the key in. Most of the time on mine I have to hit it a couple of times until the intake and reeds get completely wet.
 

F_R

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Re: 25 HP Johnson primer solenoid - I'm stumped!

I reckon you motor must be different than mine. On mine the primer fitting is at the carburetor flange, which is between the intake manifold and throttle butterfly. Thus, it is exposed to manifold pressure (vacuum), and sucks fuel. If there is not lower pressure in the manifold it won't run anyway.
 

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Dhadley

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Nope, they're all basically like that. They inject fuel behind the carb. That particular one injects directly into the intake runner and reed cage. The idea is that it gets fuel to the reeds before the motor ever turns over. That way when you do turn it over the fuel is already at the point it gets pulled into the crankcase. That's why a primer motor will start quicker than a motor with a choke.

Some of the early primer model crossflows injected directly into the intake by-pass area. The theory was that it went directly into the intake port. It did but until the reeds got wet the motor would tend to spit back at a dead idle. They moved the cf injection point to the top of the carb very much like your carb.

Their whole idea (of primer vs. choke) was that you no longer are depending on the carb to supply fuel to start a cold motor. The carb itself does not pull fuel from the primer or add pressure to it. Pressure to the primer is from the bulb or the fuel pump itself (the primer is fed from the outlet or pressure side of the pump). The primer is just an electronic valve. When you activate it, it releases fuel that's under pressure.
 

F_R

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Bye.
 

rrc0

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Re: 25 HP Johnson primer solenoid - I'm stumped!

I am impressed by my first post on this forum. Great information. Thank you for exlaining the primer solenoid's operation. The photo incldued by FR is the same primer and hose connection as mine. So back to why mine does not squirt fuel. Two replies said clean it. Do I remove the 4 screws shown on diagram in front? More complete breakdown? How could I tell if the starter is drawing all the power? It is a brand new Die Hard marine starting battery. Very frustrated that this motor runs great but will NOT cold start without removing hood, moving red lever to manual and squeezing bulb.
 

Dhadley

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Let's look at what we know about your issue. We know fuel is getting to the primer based on the fact that when you test it manually it suirts fuel. We also know the priner solenoid works based on the fact that you say it suirts fuel with the key after the motor is running.

Have you ever primed the line and tried it with the key without moving the red lever first? By trying it I mean having the primer line off so you see it squirt.
 

rrc0

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Yes. Pulling line off at carb (with fuel system pressurized) and pushing in key (both at ON and Crank position) yields no squirt. That is the frist thing I tried. Summary:
1. Auto position, key on, key pushed = no squirt
2. Auto position, key on, key pushed, engine cranking = no squirt

1. Manual position and gas line bulb squeeze = squirt
2. Auto position engine running, key pushed = squirt
 

Dhadley

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Re: 25 HP Johnson primer solenoid - I'm stumped!

What happens if you squeeze the bulb til firm then flip the red lever manually (without squeezing the bulb again)?
 

Joe Reeves

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Re: 25 HP Johnson primer solenoid - I'm stumped!

As Dhadley states......

1 - Remove one of the small primer lines from the carburetor or intake manifold.

2 - Have the RED lever over top of the primer solenoid, facing the other end of the solenoid (automatic position).

3 - Pump fuel primer bulb up hard.

4 - With engine NOT running, turn the key to the ON position, then push the key inward.

Fuel should shoot out of the primer solenoid hose due to the pressure in the fuel primer bulb. If it does not, dismantle and clean the primer solenoid as mentioned previously.

If fuel shoots from the primer solenoid hose with the engine running as you state in your last post (and previously), there is no reason that I can think of why it would not function otherwise.
 

Dhadley

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Re: 25 HP Johnson primer solenoid - I'm stumped!

Joe, the only thing I can think of if it won't squirt under manual line pressure is that it may be losing line pressure. IE- squeeze the bulb but before he gets to the key switch the pressure bleeds off. Like a bulb that has no check valves and is hooked to a tank with no anti-siphon valve.

Once running the fuel pump provides constant pressure the primer will work properly. He does state that with the manual valve open and then he squeezes the bulb, it squirts. Possibly losing the line pressure?
 
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