Oil & Fuel GC1705 Fuel Pump

[Radiodial]

My low-hour but out-of-warranty GC1705 has developed hesitation and stumbling at power above 1800rpm. Did the basics: drained and flushed tank, new filter, bleed everything to the Injector rail, had the injectors cleaned and tested, all with no effect. Only clue I have is that when you first turn the key on and warm up the glowplugs, I swear the fuel pump used to run steady and then only click intermittently once pressure was reached. Now it just runs steady all the time, rat-tat-tat-tat-tat.
What all does your GC's do? Fuel pump steady or intermittent with the just the key switched to on?

RJ Dial
Mendocino, CA

 

[Dmacleo]

my 2010 gc2400 does the rat-tat-tat-tat-tat key on engine off.
was curious as not run today.
68 deg ambient, set throttle 1/4 way turned key on. let it tat away 60 seconds. turned to start. turned over 5 times running.
let run 2 minutes then turned off for 5.
same throttle.
turned key on for 30 seconds (yup tat away) then turned to start. before full 2 turns engine running.
only time had issue with starting was when I had fuel line break right after pump but that left evidence on ground. red evidence..

but starting ok and power above certain rpm are not the same. get a fuel pressure check done.

all this key on crap means nothing. all that matters is fuel pressure when running and that leads to governor stuff.

 

[zzvyb6]

sounds more like a dirty air filter. All my fuel pumps rat-tat with key on.

 

[WranglerX]

THE Rata tat-tat is the electric lift pump between tank and fuel injection pump....

 

[Radiodial]

THE Rata tat-tat is the electric lift pump between tank and fuel injection pump....

Correct, but with just the key on, does the pump clicking go intermittent after a few seconds, or does it just keep steadily clicking away?

 

[Radiodial]

Folks are misunderstanding my question, let me try again. Does the pump run continuously with the key on?

I'm trying to determine if I have a fuel pump issue to explain the loss of power at high RPM. I crimp the line just before the Injector pump, and mine keeps running, which could indicate that the pump is bad, or it could just be the pump has an internal pressure bypass.
RJ

 

[hube2]

When the key in the on position, with the tractor not running, there is a continuous clicking. It does not stop or become intermittent. This is normal and this is what my tractor has done since day 1.

This is my understanding: There is a pressure sensor of some type in the pump. The pressure sensor causes a relay to cycle turning the pump off so that it does not build too much pressure and then turning the pump back on when the pressure drops. The continuous clicking is the relay that is switching the pump off and on. It is hard to tell but the clicking stops when the engine is running because the pressure never gets to a point to trigger the sensor.

 

[Radiodial]

When the key in the on position, with the tractor not running, there is a continuous clicking. It does not stop or become intermittent. This is normal and this is what my tractor has done since day 1.

This is my understanding: There is a pressure sensor of some type in the pump. The pressure sensor causes relay to cycle turning the pump off so that it does build too much pressure and then turning the pump back on when the pressure drops. The continuous clicking is the relay that is switching the pump off and on. It is hard to tell but the clicking stops when the engine is running because the pressure never gets to a point to trigger the sensor.

Thanks, so that eliminates the pump failing at high RPMs as the source of the problem. Kinda verified that by also loosening the nut on each injector while the engine is running. Plenty of fuel pressure, and the engine stumbles when I do that to each of the 3 cylinders, indicating the injectors are working.
This is a mystery!
RJ

 

[Dmacleo]

runs all the time just can't hear it w/ engine running of course. had a fuel leak on mine right at the pump output so had to check that some time ago.
I would check air cleaner as mentioned above.