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1988 25 Johnson choke

OK if there is a bulb in the supply fuel line what purpose does it serve other than a common choke, when would a person ever need to pump this apparatus?
 
One has nothing to do with the other. The bulb in the hose only fills the carb nothing more does not put fuel in the motor. The primer pushes fuel into the motor itself right behind the carb makes starting much easier. If you just pump the ball in the line and try to start it you will be pulling for a long time. Anytime you cold start the motor you need the primer. There is NO choke on your motor only the primer.
 
When the motor is cranking the fuel pump provides pressure to this primer ( electric valve ) gadget.------------So when you are cranking you push the key in on the electric start models.----This action opens the valve and sprays fuel into the motor for near instant starts.---------
 
Put a carburetor rebuild kit in after i cleaned the carb, and noticed the primer pump does not pump any fuel with the lines off and the bulb tight. When i squirt gas into the carb it fires right up. Gas comes out of the outlet of the fuel pump when i pump the bulb but does not appear to be going in the carb.
 
Just so we know that we're all on the same page..... that engine could have one of two type primer setups.

Does your engine have the electric "Fuel Primer Solenoid" inside that has a RED lever on one end inside with the powerhead.... OR..... does it have the "Hand Choke Pump" located on the front outside portion of the engine?

If the "Fuel Primer Solenoid", the RED lever must be pointed straight at the other end of the solenoid... and should "Click" when the key is in the ON or START and the key is pushed in at the ignition switch. If with the key pushed in and there is no "Click", check for voltage at the terminal of the solenoid.

If voltage is not present, find out why. If voltage is present and still no "Click", the solenoid is faulty.

If voltage is present and the "Click" is there, fuel should shoot out of the small hose that would normally be connected to a fitting at either the carburetor or the intake manifold, whichever the case might be.

Let us know in detail what you find.

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(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 pa$$ 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 pa$$ageways. 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.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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That manual primer pump has to be operated before engaging the starter.-----------It squirts fuel into the intake manifold of the engine for near instant starts.---------Or hurry and get an operators manual.-----Or hurry and ask your local shop to instruct you on how this works.-----------Learn how to start this motor as it will save you some coins in the future.
 
OK, well its running now but only for a short time, the mixture screw is backed out 14 turns just like my buddies motor. It idles for a few minutes and then just shuts off, I can pump the primer and it will start right back up and repeat the same process. Could it be a timing issue? While I am asking just how do ya time this thing.
 
1-1/2 turns is the usual.-------------------What is the history on this motor ? ----What other trouble shooting has been done ?
 
344mafia said:
How many turns then would be ideal for a starting point?
Click to expand...

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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History is the motor sat for a very long time, once it was running its been a pain to keep it idling. $500.00 was just spent on it and it does the same stuff idles awhile then dies and is hell to crank back up. Now it cranks easy but starts that mild backfire stuff and shuts off, even with the idle as high as i can get it by turning the handle it just slowly falls off and dies. I will try the 1-1/2 turns tomorrow and see if that works, by the way I have tried two different gas tanks and bulbs and I get the same results. Thanks guys for all the help.
 
Well I ran the motor, started at 1-1/2 turns out all the way till 1/2 turn out at on several occasions it would idle pretty good. As always it would just die like I pushed the kill switch. So is this a fuel pump problem or is it sucking air from somewhere.
 
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