Starts without squeezing primer bulb, then dies

[IDFISHER]

I have a '95 60 HP Johnson that after sitting a while (hour +) will start without squeezing the primer bulb but then it will use up all the gas in the carbs and wont start/run again until I refill the carbs with the primer bulb. After that it will run just fine at mid to full throttle, still struggles at idle at times (there's another thread on that). In theory, if it starts, shouldn't that be enough for the fuel pump to start drawing fuel out of the tank and into the carbs without needing the primer bulb?

Could this be a carb or a fuel pump/delivery issue? Has the original VRO pump with the oil delivery disabled. I premix 50:1

- spark has been tested and is good
-compression is dead even across all 3 cylinders, but in the mid 90s which i understand isn't ideal.
-new head gasket installed

 

[racerone]

The fuel pump works on pressure pulses.-------I would test run with another tank and hose.-----The primer bulb is nothing but a manual pump to fill the carburetors.----It has nothing to do with running of the motor.----Fuel just goes through it.

 

[IDFISHER]

The fuel pump works on pressure pulses.-------I would test run with another tank and hose.-----The primer bulb is nothing but a manual pump to fill the carburetors.----It has nothing to do with running of the motor.----Fuel just goes through it.

Thank's, I'll try that. So what would cause the running motor to not be able to draw fuel out of the tank and into the carbs and need to be re-primed?

 

[racerone]

Defective check valves on the air motor of the VRO.---Defective fuel diaphragm on the VRO.-------Plugged pulse limiter for the VRO.-----Air leaks on hose or INSIDE the fuel tank.----There is an option to install a basic fuel pump ( 65 HP commercial model ) on your motor.

 

[IDFISHER]

Defective check valves on the air motor of the VRO.---Defective fuel diaphragm on the VRO.-------Plugged pulse limiter for the VRO.-----Air leaks on hose or INSIDE the fuel tank.----There is an option to install a basic fuel pump ( 65 HP commercial model ) on your motor.

Would any of these things be more prone to show themselves at idle and not high speed? I can run all day at WOT and never miss a beat but it seems to have issues drawing fuel at idle.

 

[racerone]

Simple fact----I am too far away to do hands on work / inspection on your motor.----What other trouble shooting have you done ?

 

[IDFISHER]

Simple fact----I am too far away to do hands on work / inspection on your motor.----What other trouble shooting have you done ?

Just compression and spark so far. Not sure what else to try for this particular issue. I'm not an expert by any means which is why I'm coming here to ask the experts for things to look for, things to troubleshoot, etc.

 

[GA_Boater]

What happens when you squeeze the bulb before starting? It may not be running long enough to draw gas from the tank to the carb if the hose drains back to the tank..

Racer gave a good list of things to check.

 

[IDFISHER]

What happens when you squeeze the bulb before starting? It may not be running long enough to draw gas from the tank to the carb if the hose drains back to the tank..

Racer gave a good list of things to check.

When I squeeze the bulb before starting, it fills the carbs, gets firm and seems to run fine. I had just assumed that once the motor starts, it immediately begins to draw fuel from the tank. Maybe it needs more fuel to run for a certain length of time before it can get from the tank to the carbs?

 

[jakedaawg]

As was previously said, your next step should be to beg borrow or steal a known good portable tank AND different known good fuel line and bulb.