LTX 1040 wont run

[notmeofficer]

Hello Cub Cadet folks.. I am having an issue with my tractor and I need some suggestions in diagnosing the issue

tractor has 25 hours on it.. long since out of warranty

Was running and mowing and it died.. no restart

Tractor is like new...
Has fresh battery
perfect grounds
main fuse ok
has spark...


Will run if I directly spray gas in carb

I do not smell any gas when I crank

Fuel fresh/full/flows freely/lines not kinked/filter clean

I suspect

Fuel solenoid?



It has 12 volts coming in.. not sure how to check if its working

or one of the safety switches.. (if there are more than one)
Seat?
Mower deck?

Not sure where those are or how to check


Any suggestions would be most welcome

Thank you very much

 

[Bob_Bainbridge]

Safety switches would prevent engine from cranking so you can eliminate them. If it runs with gas sprayed into carb, you definitely have a fuel delivery problem. I gather that you checked the fuel coming out of the filter OK. If it has a shutoff solenoid check for 12 volts across the coil. Remove the hose at the carb and see if fuel comes out. If it does you may have a stuck float/needle valve in the carb. If fuel doesn't come out trace the hose back towards the tank to find the culprit. I'm not familiar with the 1040 and don't know if it has a shutoff valve or possibly a fuel pump which could be failing. The larger Kohler twins have a rocker arm actuated pump.

Bob B.

 

[notmeofficer]

Thank you Sir
I will look at what you suggested
The internet lists a fuel pump for this model Kohler...but I didn't see one... although I may have mistaken a device for a smog piece that looks like the picture of one... but its static... with no power to it so I don't see how it could be a pump... its located above the carb under the motor cowling

 

[Dave M7040]

I know your initial post stated fuel runs freely but I am uncertain how you determined this.
The most critical test is fuel delivery to the carb. not just at the filter where gravity will bring the fuel as it is lower than the top of the tank.
A pump is needed to get thje fuel up to the level of the engine which is above the tank especially when the tank level is low.

The fuel pump is typically a vacuum operated pump located on the engine itself.
Here is a typical picture. Ebay for $10 to $40 depending on if it is a China made product or American

The brass small plug in the center of the pump is actually an air filter made from particles of brass bonded together so air can pass through.
This allows the pump diaphragm to move back and forth under the vacuum of the engine and deliver the fuel.

Trace the black fuel line shown in your first photo and you should find it.
It will have a black line for fuel from the tank and then the output line to the carb,
Finally there will be a vacuum line going to the intake manifold on the engine.
Disconnect the fuel line at the carb and direct it into a container as someone cranks the engine.
Fuel should be coming out in pulses.
If not a new pump may be in order.
If the pump tests OK then the problem may be a stuck float or possibly the fuel cut off solenoid may be stuck.
To test the fuel delivery solenoid remove it from the carb and apply 12 volts with the solenoid body being grounded.
You should see the solenoid plunger retract. When you shut down the engine the plunger is pushed up by the spring to stop fuel delivery.
Remember you are working with a flammable liquid so dont do this inside your garage where a fire could result.
Dave M7040

 

[notmeofficer]

I know your initial post stated fuel runs freely but I am uncertain how you determined this.
The most critical test is fuel delivery to the carb. not just at the filter where gravity will bring the fuel as it is lower than the top of the tank.
A pump is needed to get thje fuel up to the level of the engine which is above the tank especially when the tank level is low.

The fuel pump is typically a vacuum operated pump located on the engine itself.
Here is a typical picture. Ebay for $10 to $40 depending on if it is a China made product or American

The brass small plug in the center of the pump is actually an air filter made from particles of brass bonded together so air can pass through.
This allows the pump diaphragm to move back and forth under the vacuum of the engine and deliver the fuel.

Trace the black fuel line shown in your first photo and you should find it.
It will have a black line for fuel from the tank and then the output line to the carb,
Finally there will be a vacuum line going to the intake manifold on the engine.
Disconnect the fuel line at the carb and direct it into a container as someone cranks the engine.
Fuel should be coming out in pulses.
If not a new pump may be in order.
If the pump tests OK then the problem may be a stuck float or possibly the fuel cut off solenoid may be stuck.
To test the fuel delivery solenoid remove it from the carb and apply 12 volts with the solenoid body being grounded.
You should see the solenoid plunger retract. When you shut down the engine the plunger is pushed up by the spring to stop fuel delivery.
Remember you are working with a flammable liquid so dont do this inside your garage where a fire could result.
Dave M7040

Dave

Kudos to you for very clear diagnostic directions. Thank you so much

 

[JRobyn]

What Dave said. If it will run a bit on carb cleaner or starting fluid, you have a fuel problem.

You can actually also test the fuel pump by removing it, RINSING IT with water, and applying little pressure/vacuum pulses to the pump pulse line with your mouth while submerging the input line in some water. Of course, if you do this and the pump is ok, thoroughly dry it before reinstalling.

Since it seems to have suddenly quit, the fuel solenoid is the most suspect IMHO. Sometimes you can test it without removing by listening very closely while a helper switches the key off and on. You should be able to hear a slight click. Mine has a separate/dedicated ground wire that was broken. So check the wiring condition closely.

- Jay

 

[rcbe]

OP - 12vdc solenoid at bottom of carb is NOT a fuel solenoid,per se. It is an after-fire solenoid, meant to minimize the loud bang that sometimes occurs when shutting down and only controls fuel flow to the carb power circuit...not the idle circuit.
If you are able to confirm fuel flow to the carb, can hear the solenoid "click" when ign key is turned on, get the engine to "pop" by spraying rattlecan carb cleaner directly into carb throat while attempting to start, then time to pull carb, fully tear down, soak overnite in liquid carb cleaner, probe EVERY orifice/passageway with a small dia stiff brass wire/magnifier and blow out w/compressed air; rebuild carb clean with new kit, especially new needle/seats and gaskets.
good luck.

 

[notmeofficer]

Thank you everyone
Weekend project coming up

I wish all of you a great week

 

[motoracerx]

New guy here. I was having the same problem as described by the OP.

I just installed a new carburetor solenoid repair kit straight from Cub Cadet.

I have spark. Good compression. The solenoid is clicking and plunger was engaging/disengaging prior to attaching it to the bottom of the carb. Fuel is flowing freely from the in-line filter to the carburetor.

The mower ran fine a week ago, shuut it off, no restart. I could not hear or feel the carb solenoid clicking/engaging, so I ordered the new solenoid kit w/ heatshield/hardware/gaskets.

I guess I'll check the fuel pump/diapragm thingy as described above. It's hard to believe that the fuel pump and carburetor solenoid went out simultaneously.

OP, report back!!

Any other ideas or suggestions fellas? Thanks.

 

[motoracerx]

Just checked spark again, it is great. But there is not fuel 'wetness' or smell on the brand new and correctly gapped sparkplug?

When I had the carb off earlier, I generously sprayed carb cleaner throughout the carb. Guess I'll take it off and tear it apart.

Oh, and I see no fuel pump black thing as described above.

 

[rcbe]

moto - trying to interpret what you wrote, suggest you do a simple electrical chk at the carb afterfire solenoid electrical connection with a voltmeter or continuity tester to confirm you are getting 12vdc to the solenoid when you turn on the ign sw. You may well have a problem in that circuit or a failing ign sw, particularly if you are still getting good fuel flow at the carb...
just saw your latest post - yeah, would still chk/fix above first; then try start. If no start, put a cuppla shots of rattlecan carb cleaner right down carb throat while cranking. If still no effort to start, then pull carb, tear down, soak in liquid carb cleaner overnite, probe EVERY orifice/passageway with a small dia brass wire and magnifying glass, blowing out same with compressed air to dislodge crap; rebuild with new carb rebuild kit using only new needles/seats and gaskets.

 

[motoracerx]

And now, if i throw some fuel into the carburetor to where it's getting into the cylinder, I'll get one big backfire, and that's it.???

 

[motoracerx]

moto - trying to interpret what you wrote, suggest you do a simple electrical chk at the carb afterfire solenoid electrical connection with a voltmeter or continuity tester to confirm you are getting 12vdc to the solenoid when you turn on the ign sw. You may well have a problem in that circuit or a failing ign sw, particularly if you are still getting good fuel flow at the carb...

Before I attached the new solenoid to the carb, I made all electrical connections, turned the key on, and the plunger on the solenoid would engage and disengage when I turned the key off and on. I can clearly hear it click when I turn the key off and on with everything together.

Prior to the new carb solenoid, there was no clicking or sound from the old carb solenoid and the plunger on the old solenoid had some drag to it...it wasn't nearly as 'springy' as the new solenoid plunger. Thouught I had this sucker fixed for sure with the new solenoid.

 

[rcbe]

about spooked to respond... is there more info coming? :confused2: try the above reply first and then post back.

 

[rcbe]

Before I attached the new solenoid to the carb, I made all electrical connections, turned the key on, and the plunger on the solenoid would engage and disengage when I turned the key off and on. I can clearly hear it click when I turn the key off and on with everything together.

Prior to the new carb solenoid, there was no clicking or sound from the old carb solenoid and the plunger on the old solenoid had some drag to it...it wasn't nearly as 'springy' as the new solenoid plunger. Thouught I had this sucker fixed for sure with the new solenoid.

OK - I.m clear on the solenoid saga

 

[rcbe]

duplicate

 

[motoracerx]

I have 12.05 volts going to the electrical connector that plugs into the new carb solenoid.

 

[motoracerx]

Sprayed carb cleaner into carb, one big backfire....just like when I tossed some gas into the carb.

 

[Dave M7040]

From Kohler engine web site, description of two possible loctions of fuel pump and operational sequence:
http://www.kohlerengines.com/onlinecatalog/pdf/20_690_01_EN.pdf
See page 21 of 76

Some engines are equipped with one of two optional
pulse fuel pumps. One is mounted to speed control
bracket, and other is mounted to air cleaner base.
Fuel pump has two internal chambers separated by
a diaphragm. Air chamber is connected to engine
crankcase by a rubber hose. Fuel chamber has an inlet
from fuel tank, and an outlet to carburetor. Inlet and
outlet each have an internal, one-way check valve.
Alternating negative and positive pressures in crankcase
activate pump. When piston moves upward in cylinder,
negative pressure (vacuum) is created in crankcase
and in air chamber of pump. Diaphragm
flexes toward
negative pressure, and suction draws fuel past inlet
check valve, into fuel chamber. Downward movement
of piston causes a positive pressure in crankcase and
air chamber, pushing diaphragm in opposite direction,
putting pressure on fuel. Inlet check valve has now
closed, so fuel is forced past outlet check valve, to
carburetor.

As suggested earlier, remove fuel line at carb and crank engine to see if fuel pulses out. Test at filter is no good as gravity brings fuel that far.
Dave M7040

 

[motoracerx]

Took carb off. Remove float. Noticed that the needle is not completely vertical, it is leaning to one side.....it is off center at the bottom of the carb.

Here's a pic from looking from the bottom of the carb. The needle feels like it is in a bind and not wanting to move at all.