Primer Bulb

FreeBeeTony

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Have twin '95 175 Jojnsons....
Primer bulb always pumps up strong after 3-4 squeezes on port engine.
Stb engine does not get "hard".....even after more pumping, engine starts fine but needs more pumping in colder weather.
I replaced the primer bulb on stb engine this spring w/o any change.
Another problem I think is related is that after running for a while (~an hr or so) and shutting down to fish or have lunch....same engine has trouble getting up in RPM's......has problems getting past ~1500RPM......tends to stall out (this is in gear)......like I have to sneak up on it, once it gets up to 2000RPM's it's good to go.
Have dual tanks, doesn't matter which tank is being used.

What would cause the bulb not to get hard? I'm thinking these issues are related.......
I tried pushing the key in today when I was having problems getting up in RPM w/o any help.
Next time going to try pumping the bulb!
 

F_R

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Many primer bulbs have lousy check valves making them not real good pumpers. However, once you get gas to the carburetors, the primer bulb does nothing. You could actually remove it and throw it away, and it would still run---till you run out of gas.
 

lindy46

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Switch the bulbs around and see what happens. Could be a float stuck on stbd engine.
 

dingbat

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You should be able to pump the ball until you can pump no more.

If the primer bulb doesn’t get hard, a float(s) is stuck or misadjusted, fuel pump diaphragm is leaking or the primer solenoid circuit is leaking.
 

FreeBeeTony

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If the primer bulb doesn’t get hard, a float(s) is stuck or misadjusted, fuel pump diaphragm is leaking or the primer solenoid circuit is leaking.

I rebuilt all 12 carbs (twins) myself so I don't think it's a sticking float. so I guess I should see gas leaking somewhere.
 

dingbat

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I rebuilt all 12 carbs (twins) myself so I don't think it's a sticking float. so I guess I should see gas leaking somewhere.

Never rule out a problem because you worked on it earlier. Won a free trip to China because I assumed.......

Fuel going somewhere...have you checked the fuel pump
 

FreeBeeTony

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Did a static test this morning........pumped the SH!T out of the bulb w/o getting hard.
Took the hood and airbox off......no signs of excess fuel anywhere.
Decided to remove/inspect the Pulse Limiter. Verified the blue nipple.
Was able to blow air in both directions w/o much restriction.
Sprayed w/ carb cleaner and seemed "clearer".
Is it supposed to pass air in both directions? Thought I read it was like a check valve and only pass air in 1 direction.
 

racerone

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Totally wrong !!-----The PULSE LIMITER is a flow fuse and protects the VRO fuel pump from a sudden high flow of air / pressure.-----This thing CLOSES in case of an " event " in the crankcase.------So yes it has to let air flow both ways !----If it did not flow both ways the VRO pump would not work.
 

FreeBeeTony

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OK.......understood!
Been doing more research.......is it true that the VRO pump is operated soley by the pulses coming from the pulse limiter?
So there are (3) inputs to the pump: (1) oil, (1) gas and (1) pulses from the crankcase and (1) output: oil/gas mix.
My main concern is the stumbling/stalling while accelerating after running @ 4K RPM for a bit then shutting down for a spell, Definetly seems fuel related to me.......will see if performance changes/improves after pulse limiter cleaning next time out.
If no change I'm leaning towards possibly removing the VRO for disassembly/inspection.
 

racerone

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Correct , air pulses from the crankcase run the AIR MOTOR of the VRO.------The wires are there for the " NO OIL " from the pump warning system.
 

FreeBeeTony

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1st.........Thanks for your continued responses.
2nd.......What do you think of my plan?
Can these pumps be rebuilt?
 

FreeBeeTony

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Update: ran boat yesterday as have in the past..........again after sitting for a while, the stb engine ahd trouble getting up to RPM again. This was after cleaning the pulse limiter.

Still need to check pumping the primer bulb more.......
 

Faztbullet

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When it is stalling have someone pump the bulb and see what happens. If nothing changes swap the vapor pumps on VS bracket and test.
 

FreeBeeTony

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Can you please be more specific........vapor pumps?

EDIT: found it...........#37 on the parts diagram. should I also swap the diaphragm (#38)?
 
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