Johnson 25HP surging

[grandpaul]

1995 Johnson 25HP outboard (tiller)

Carb thoroughly cleaned, jets cleared w/ thin wire strand, float needle clean
ALL passages squirt clean with Berryman's spray
New OEM spec spark plugs
Gas tank flushed, fresh gas & oil, 50:1
Cooling tattletale squirts
Fuel line cleaned by pressing both check balls and draining completely
Fuel pump strainer perfectly clean, to tears or holes
Pumped up entire system w/ fuel line OFF of carb till fresh fuel squirted out
Fuel line pumps up, carb choke squirts visibly in carb throat
Engine starts and runs okay in the driveway with hose connection for cooling
Take off and run up to full throttle, okay for a minute, then engine starts surging
Surging stops if I keep pumping the bulb, otherwise surges, sometimes dies

??????

Could this be due to leakage where fuel line connects to engine? it will dribble fuel if I pump it up and keep pumping.

Should there be an o-ring there, on the inlet pin @ engine fuel line connection?

This is EATING MY LUNCH.

Thanx.

 

[bobbyc]

Should be an o-ring at each end of the fuel line...if its missing or damaged, surging will occur

 

[Boobie]

Fuel pump could be bad.

 

[johnnygjr]

Pumping primer bulb simulates a fuel pump going bad,still replace o-rings and test run. Keep us posted

 

[nccatfisher]

Pretty good rule of thumb is if you have a fuel leak visible when you create pressure on the system then there will be an air leak into the system when it is calling for fuel. I believe you have found your problem, you just need to repair it.

 

[grandpaul]

Pretty good rule of thumb is if you have a fuel leak visible when you create pressure on the system then there will be an air leak into the system when it is calling for fuel. I believe you have found your problem, you just need to repair it.

Yep, just need the recoil starter spring and it'll go back together.