primer on my 20hp rope start

[Newyota]

Have this new to me 1985 johnson 20hp with a primer instead of a choke on it and wonder how many times should this be pumped and should it be pushed all the way back in when starting or leave out part way till it starts?Will this vary by engine and condition.?

 

[gm280]

Newyota, I have never worked on or used such a primer system like your before. But looking at the exploded view of your priming system, it looks like you push it in for an additional shot of fuel for cold starting. I would think you would push it once and see if that started the engine when pulling the rope. If it doesn't then push two times and try. Once you figure out the proper number of times, that is what you will use there after. But I would only push it in once for starters. Maybe others that have used such a primer can chime in for their experiences. JMHO

 

[flyingscott]

Pump it once or twice and leave it out and start the motor until it warms up and push it back in.

 

[SeaDooSam]

If it is a button you press I would say 2-3 times. Don't do it too much or you'll flood the carb.

 

[Newyota]

thanks..will do..

 

[R DAVIS]

The primer on these motors does NOT squirt fuel into the motor. There is no choke on these motors.

It is only a (normally open) solenoid which opens a (normally closed) valve inside the primer assembly, allowing the fuel pump to squirt fuel into the intake, but only as long as the primer solenoid is activated (this means only so long as the key is being held in, which is holding the valve open, and the engine is being cranked). As soon as you quit pushing in on the key, the valve closes and shuts off fuel flow through the solenoid. Pumping it does nothing except cause the solenoid to open and close each time you push in on the key. You can hear the solenoid click every time you push in on the key. If you pump it without cranking the motor, you are doing nothing except making a clicking noise, as no fuel is going anywhere.

What you want to do when the engine is cold, is to push in on the key WHILE CRANKING the motor. The motor should start quickly if the throttle is in the fast idle position. You might need to pump the solenoid momentarily while cranking, until it starts to fire, but don't hold it open more than a couple seconds at a time while cranking, to avoid flooding.. As soon as it starts, let up on the key (quit pushing it in) so as not to flood the motor. If it tries to die, push in on the key for only a half second or so. You may need to do that several times until the motor starts to run on its own. You may also need to adjust the speed of the motor with the fast idle lever while it's trying to start and during warm up. Do not use the primer when the engine is warm so you don't flood it.

Normally the red lever on the solenoid should be in the run position which is as far to the right (clockwise) as it will turn. If your battery is dead and you have to rope start it, turn the red lever 90 degrees to the left (so it's at a right angle to the run position). That manually opens the primer valve. You will then need to turn it back to the run position as soon as it starts. You can also use the manual lever to start your motor in case the primer solenoid or its switch fails.

If your primer has a Schrader valve on it, the purpose is to hook up a can of "engine tuner" to clean carbon out of the motor while running it.

Be careful not to over tighten the screw on the strap holding the primer solenoid in place. That may cause it to crush the valve inside the solenoid. It should only be barely snug, not too tight.

 

[flyingscott]

The primer on these motors does NOT squirt fuel into the motor. There is no choke on these motors.

It is only a (normally open) solenoid which opens a (normally closed) valve inside the primer assembly, allowing the fuel pump to squirt fuel into the intake, but only as long as the primer solenoid is activated (this means only so long as the key is being held in, which is holding the valve open, and the engine is being cranked). As soon as you quit pushing in on the key, the valve closes and shuts off fuel flow through the solenoid. Pumping it does nothing except cause the solenoid to open and close each time you push in on the key. You can hear the solenoid click every time you push in on the key. If you pump it without cranking the motor, you are doing nothing except making a clicking noise, as no fuel is going anywhere.

What you want to do when the engine is cold, is to push in on the key WHILE CRANKING the motor. The motor should start quickly if the throttle is in the fast idle position. You might need to pump the solenoid momentarily while cranking, until it starts to fire, but don't hold it open more than a couple seconds at a time while cranking, to avoid flooding.. As soon as it starts, let up on the key (quit pushing it in) so as not to flood the motor. If it tries to die, push in on the key for only a half second or so. You may need to do that several times until the motor starts to run on its own. You may also need to adjust the speed of the motor with the fast idle lever while it's trying to start and during warm up. Do not use the primer when the engine is warm so you don't flood it.

Normally the red lever on the solenoid should be in the run position which is as far to the right (clockwise) as it will turn. If your battery is dead and you have to rope start it, turn the red lever 90 degrees to the left (so it's at a right angle to the run position). That manually opens the primer valve. You will then need to turn it back to the run position as soon as it starts. You can also use the manual lever to start your motor in case the primer solenoid or its switch fails.

If your primer has a Schrader valve on it, the purpose is to hook up a can of "engine tuner" to clean carbon out of the motor while running it.

Be careful not to over tighten the screw on the strap holding the primer solenoid in place. That may cause it to crush the valve inside the solenoid. It should only be barely snug, not too tight.

He has a tiller with a manual primer it absolutely SQUIRTS fuel in. Everything you are describing is the electric primer which he DOES NOT have.

 

[82rude]

Used primers for years and years on snowmobiles.theres no need to leave the primer out atall.Every motor is different but for example I will use my 670 h.o. ski-doo as an example.On a -30 day 1 1/2 pumps with the primer left in for starting.Warmer days was 1/2 pump that's it .Never failed to work.You may have to fool around a tad but you will get it and the 20 will start perfectly every time.

 

[flyingscott]

Used primers for years and years on snowmobiles.theres no need to leave the primer out atall.Every motor is different but for example I will use my 670 h.o. ski-doo as an example.On a -30 day 1 1/2 pumps with the primer left in for starting.Warmer days was 1/2 pump that's it .Never failed to work.You may have to fool around a tad but you will get it and the 20 will start perfectly every time.

I had 2 of those 25 hp evinrudes with primers. You leave the primer out because it's like letting it warm up with the choke on.

 

[82rude]

Never owned one so I have to bow to your experience though I don't see how it would act as a choke unless it also closes the plate?Sorta sounds like an enrichiner system on a sled?Ok just read the service manual on the 20 hp .its a push pull system and by rights you shouldn't have to leave out atall .It mearly squirts fuel into the system and by rights should not pull fuel in on its own unless the o rings are faulty.flyingscott did you leave it out part way as a method of giving it a extra squirt if the motor acted up?Never knew outboards had that system ,interesting.

 

[flyingscott]

Never owned one so I have to bow to your experience though I don't see how it would act as a choke unless it also closes the plate?Sorta sounds like an enrichiner system on a sled?Ok just read the service manual on the 20 hp .its a push pull system and by rights you shouldn't have to leave out atall .It mearly squirts fuel into the system and by rights should not pull fuel in on its own unless the o rings are faulty.flyingscott did you leave it out part way as a method of giving it a extra squirt if the motor acted up?Never knew outboards had that system ,interesting.

There is no choke plate on that motor. The primer does push fuel through and squirt it. But once you pull it all the way out both ports are open and fuel runs through it ti richen up the mixture. Since the primer is connected to the float bowl once the fuel pump starts working it pushes fuel through the primer. This allows it to provide fuel for a richer mix for warm up. The only way to shut the primer off is to push it in fully. When the orings go bad the fuel leaks right past them and you have a rich running motor. A check valve prevents the primer from having fuel and air run backwards into the float bowl. This is not a simple primer like on a snowmobile much more to it.

 

[82rude]

Yes it seems by your description to be much different than the simple sled primer.Thanks for the explanation.

 

[flyingscott]

that's why when you could still buy the complete assembly they were around $100.

 

[82rude]

ouch!

 

[racerone]

The primer draws fuel from the float bowl.---That fuel is NOT pressurized by the pump.-------If primer is pulled out fuel will be drawn in due to suction in the intake manifold.