2005 M6800 Rops. Shuttle Shift. 1247 hrs. Intermittent starting problems - need help please.

[Gus1957]

New here: Bought the tractor new. 18 years old.

Tractor always sits outside. Always great starting in cold below 20F to -20F. My snow plow tractor.

Fuel indicator light on even though fuel gage works and there is plenty of fuel above 1/2.

Been having odd starting symptoms for a couple weeks of not cranking quickly when turning key. Key has been weak and slow to return. When I seemed to snap it more quickly tractor started.Many times I've had to break ice off of it to be able to turn it. So I changed it with no difference.

Battery, Starter/solenoid checked. Ground strap to frame removed and cleaned - silver plating looked clean.

I turn key and hear feel solenoid click and I can feel it. Tractor turns 2x and stops.

I'm thinking a safety switch or other solenoid in starting circuit bad?

Wednesday it was 30F and light snow. Tractor just started and ran 4 hours strong no issues. Turned it off to unload firewood outside and wouldn't restart.

Next morning 16F. Went out used glow plugs and fired right up like normal. I was able to get it in the barn to work on it. Tried shutting it off a few times and it restarted. While in barn changed oil/filter and fuel filter. Remove starter and battery to do checks. After 8 hours it started right up. Went to get more oil and 1 hour later back to no start.
Friday went and bought ignition switch - won't start now.

I've read that the Fuel Indicator light - ON can serve as a Charging Indicator Problem too - but battery is fully charged?

All ideas appreciated.

Thank you!

 

[Gus1957]

42F this morning. Had the battery on slow charge since I had been trying a lot to start it yesterday. Put it back in tractor.
Different ;
Tractor turns over fast but won't start like no fuel?

 

[Russell King]

May have water in fuel that is freezing up and stopping fuel flow? Look for water in a water separator if you have one on the tractor.

Perhaps summer blend fuel is gelling up?

I have no idea about the key switch problem now that it’s brand new

 

[GreensvilleJay]

When did you replace BOTH battery cables ???
'turning slowly' is usually a sign of old, corroded cables can pass volts but NOT amps.

 

[Gus1957]

May have water in fuel that is freezing up and stopping fuel flow? Look for water in a water separator if you have one on the tractor.

Perhaps summer blend fuel is gelling up?

I have no idea about the key switch problem now that it’s brand new

It has winter mix fuel with Power Service additive as well. Not cold enough. I changed fuel filter the other day and cleaned out water separator while I was waiting for oil to drain.

 

[Gus1957]

When did you replace BOTH battery cables ???
'turning slowly' is usually a sign of old, corroded cables can pass volts but NOT amps.

Both cables were replaced 6 years ago with the new battery.

 

[fried1765]

Both cables were replaced 6 years ago with the new battery. View attachment 118194

Have you had the "SIX" year old battery load tested, and have BOTH ends of the cables been cleaned in past six years?

 

[Gus1957]

I took battery out and took it to NAPA and they load tested it and I watched it in the green as ok.

Battery cables are clean and had di-electric grease on them. I put it on terminals too when I reinstalled battery. I even took ground wire off the frame and checked it. Silver plating was bright with no corrosion.

 

[Russell King]

Ugh!
I would start with seeing where you have good fuel flow. I like to start at the middle like at the filter but others say to start at the injection pump since that is where you really are concerned about.

You should also verify that the air intake and exhaust system are clear of obstruction and the filter is not blocked.

please state which tractor is giving you the problem since you listed two in your profile

 

[Gus1957]

Hello Russell,

M6800. TY

 

[GreensvilleJay]

slow spinning starter won't be fuel related....
remove starter, test on bench,see how fast it spins.

could be a bad starter solenoid. the high current one not the control or 'starter ' relay.

if the attached drawing IS yours, the solenoid is on the starter. You 'may' be able to bypass it to put 12v on the starter. I don't know, other should that have worked on similar units.

Also there may be a real ,fat ground wire between engine and frame, again others may know.

If it spins fast on the bench and slow on the tractor, look for bad ,high current wires.

hmm, jumper a good battery to the 060 terminal and try to start. if it spins fast then fat +12 cable from battery to 060 is bad.

 

[Russell King]

Hello Russell,

M6800. TY

Sorry I see that is in the title now!

Since I think you said it is fuel related (spins normal but won’t start) but @GreensvilleJay thinks it is still an electrical problem I guess you should state what you are having a problem with today.

I am going to bow out since I seem to be doing no good anyway!

 

[Gus1957]

Tractor is back running smoothly with 5 restarts after removing water separator and cleaning out orifices and passages. There was some back slimy stuff in there . Biodiesel ?
The only concern now is that the Fuel Idiot Light came back on .
Hoping there was a Kubota Expert on here to identify the issue.

Thank you !

 

[Russell King]

Tractor is back running smoothly with 5 restarts after removing water separator and cleaning out orifices and passages. There was some back slimy stuff in there . Biodiesel ?
The only concern now is that the Fuel Idiot Light came back on .
Hoping there was a Kubota Expert on here to identify the issue.

Thank you !

There are biological growths in diesel that will grow in the tank.

Using some biocide as shown here, will help eliminate it. I believe it clogs the fuel filter so don’t be surprised if you notice the filter is clogged up faster than normal.

5 Best Biocide diesel of 2024 - Top-Rated Reviews & Deals

Glad your tractor is back to normal