New here and have issue with JD 777

[tassmannn]

I never thought I would need to be on a Small engine forum, but here I am. I have a JD 777 that seems to starve for fuel. It is a carburated engine with no ECM, and very few things to go wrong...I thought. In the past, it was the fuel pump, and when I changed it, all was right with the world. Well, I've changed the fuel filter, fuel line, return line, and even the fuel shutoff solenoid with all OEM parts (The solenoid was a bear!) I've looked at the schematics and there really isn't much to this machine. After all of this, it still will run under a load between 15-30 mins, and start to starve for fuel, at least that's my impression. If I stop and choke it, it will start up again, but then I know it's not fixed and run it back to my shop. Gas is clean and I use fuel additive K-100 in it, and use it a lot so gas sitting in the machine is not an issue. Seems like when it warms up is when these symptoms happen.

Any assistance would be greatly appreciated

 

[bertsmobile1]

The instant the engine stops whip open the fuel cap
If you hear air getting sucked in the the vent is blocked
Other possibility is floating debris in the fuel tank getting sucked down into the fuel outlet & partially blocking it .
Final one is damaged fuel lines.

 

[tassmannn]

Thanks @bertsmobile1 I will test the cap when the rain here subsides. Tank is spotless. I did see some debris on the underside of the fuel cap where mud dobbers tried making nests. Hope it is that simple

 

[davis2]

Thanks @bertsmobile1 I will test the cap when the rain here subsides. Tank is spotless. I did see some debris on the underside of the fuel cap where mud dobbers tried making nests. Hope it is that simple

Did you open the carb and ensure no debris inside? Just a thought. If you did it already, sorry to waste your time...

 

[tassmannn]

Thanks, @davis2, never a waste of time for me, and all suggestions are welcomed. I looked at the carb when I replaced Shutoff Solenoid, but didn't totally break it down. I will run the unit later today to test the cap. If the cap isn't the issue, that will be my next step.
Thanks again!

 

[tassmannn]

Well, it wasn't the cap. Stalled after 10 mins under load, and it vents fine. Guess I need to remove the carb.

 

[bertsmobile1]

BEcause of EPA regulations fuel line is now 2 or 3 layers of different rubbers
The inner 1005 petrol proof liner is very weak & can rupture
Then the petrol flowing past gets between it and the second ( fibre reinforced ) layer and swell up like a blister till it eventually chokes off the fuel supply

When a customer comes in with a problem like yours I usually remove the bonnet then fit red inline spark testers and go mow .
When the engine starts to die I watch the testers.
If they flash till the bitter end then I know there is a fuel side problem
If they stop flashing and then the engine slows down & stops I know it is an electrical problem .
I just finally completed a JD Z225 that had busted my balls with 5 warranty callouts .
Ended up being exactly that problem is the section of hose that went from the tank outlet to the fuel tap.

This thing would run for up to 2 hours then shut down, refuse to start for several days then fire right up no problems
When I checked the fuel flow from the tank it was always good .
Ended up using the auxillary tank I keep for these types of problems to work out there were no problems from the tap to the engine so I bought the JD replacement top fuel line & problem solved .

 

[tassmannn]

Update.....It was the carborator