Experiencing Intermittent Shut-down

[Wagtail]

Intermittent faults/problems are the worst!

6 months ago (my Autumn) I was happily chain harrowing a fairly flat paddock, HST in Low, revs at 2000 and I'd been at it for about 30 minutes. I'd filled the diesel in the tractor prior to the task. The FEL was raised for visibility. About 380 hours on the rig and all maintenance (50 hour oil & grease) done at the required time... when the tractor just shut down. The battery & engine lights came on as the engine 'withered' away like one of those safety switches would do. I tried to re-start = no joy.

Bugger.

Key off, I put it in Neutral, set the brake and dropped the revs. Hopped off and checked the fuel bowl (red disk at the bottom) then checked the tractor over for, well, anything. Nothing obvious. So I hopped back on and tried starting it again and, after a few turnovers, it fired back up again as if nothing had happened. OK, back to work... for about 10 minutes and the same thing happened. I turned it off, revs down, brake on, Neutral, count to 10 and re-start... It fires back up again and I'm able to finish the job.

Once or twice again it would do this over the next month. Sometimes in Low and sometimes in High, usually when I give it just a wee bit more acceleration on the FWD pedal.

So I reckoned that I was close enough to the 400 Hour maintenance period. I changed the oil & filter and the fuel filter. Did my full hydraulic oil & filter change. Greased everything and inspected the safety interlocks... the 'seat' one was a bit wobbly so I duct taped it in solid! After all of this I took it out again and it eventually happened again. Then it hit me (inspiration, nothing physical... although I may have smacked myself upside the head)... The diesel tank cap! I backed it off and have had trouble free tractoring ever since. HUZZAH!!!

Until yesterday. It's back. :thumbdown:

The only thing I've done different is top up the diesel fuel... could it be the culprit or am I missing something?

 

[Redlands Okie]

From similar post in the forum i wonder if you have a bit of trash in the fuel tank ? As the trash floats and moves around it covers the fuel outlet once in a while.
Check for collapsing fuel lines or kinks.
Clogged vent in the fuel cap or wherever you're vent is.
Loose wiring connection some where in the fuel / fire system such as at the fuel solenoid.
Safety switches , your duct tape may be loosened up by now.
And i be out of ideas for now

 

[TnAndy]

As soon as it starts to happen, jump off and check the fuel bowl again, assuming it is a clear one you can see the fuel in. Any air at all in that bowl ? Keep reading.

Had the same thing happen to my Yanmar at about 50-75 hours new..went thru changing fuel shutoff solenoid (twice, dealer, warranty), checking all the safety switches, changing fuel filters, etc, etc, and it finally turned out to be a bug floating around in the fuel tank that would drift over the tank outlet and block enough fuel to completely shut it down in a random pattern !!

Mechanic at the dealership just happened to noticed the plastic bowl partially empty (mine is located under the right fender inside the rear tire), and actually sucking inward as the engine stuttered to a stop. He pulled the fuel hose off the bottom of the tank and just got a dribble of fuel.....which would fill the bowl again in a minute or so, and allow the engine to re-start (sound familiar ?). Tractor would run fine until that bug floated back over the tank outlet, which might be a minute, or a month, and repeat the process.

They took the tank off, turned it upside down with a clean rag over the filler hole, and found the bug....wrapped in some plastic spiral shavings from where the tank was originally drilled for the outlet fitting.

Things went fine for a couple years, now out of warranty, same thing again. I bought a cheap Rigid brand inspection camera, (saved the pain it takes to remove all the stuff to remove the tank !) drained most of the fuel, and with a long set of 'grabber' tongs, pulled the next bug out of the tank.....a small wasp. A 'mud dabber' they are know as here...they love small holes to build mud nests in, pack them full of spiders to feed their young as they hatch out of the eggs laid first...they are quite aggravating insects.

I figure it got in the filler nozzle of the fuel hose I hang up on a wall (comes down from tank located above to gravity feed my fuel supply), looking for a place to nest, died, and went in the tank when I filled up one time....only explanation I can come up with for how it got in the tractor tank....not like I drive around with the fuel cap off....

 

[Wagtail]

Thanks for the replies, Mates. I have a dreadful feeling that it is a bug or debris in the tank. And, yes, we've got those bloody mud-dauber wasps down here too. I've 'capped' everything I can think of to deter them... even a cap on my diesel fuel nozzle.

After posting this thread I pondered if I'd missed anything in giving you my symptoms or what I've checked. So I just got back from going out to the shed and firing the tractor up. The coolant level is fully topped up at the 'cold' line. The tractor has always started right away and it was no different this time. I raised the bonnet before starting and checked the air filter discharge = steady 'puffing'.

When the slow-wobbly shut down does occur, the tractor has always been operating for at least 15-20 minutes. The temperature gauge has always sat solidly at the 1/3rd in the green mark.

 

[onionfmr]

I feel your pain! I went thru this exact same thing with a Massey 1643 cab tractor. It would run fine for a couple of weeks and then in one day would intermittently shutdown fives times in one run of seat time. It would go into limp mode. Tractor would start and run. But, it couldn't be moved w/o stalling. Very annoying when snow plowing. Tried everything, loosened fuel tank cap, drained diesel tank, cleaned filters, checked for bugs/dirt in tank, nothing. Ended up being a kink in the fuel line caused by the firewall insulation and length of fuel line. If the stars were aligned just right the situation happened. Apparently caused by heat. Opened up the hole in the firewall insulation, shortened the fuel line and never had the problem again in 350 plus hours of operation. Not saying this is your problem. But, worth checking.

 

[pmsmechanic]

These small tractors do not need a lot of fuel flow to keep going so what I like to do when I have a fuel system apart is to add a small 1-2" extension onto the fitting going into the fuel tank. I drill the fitting so that I can tap a small metal or brass pipe into it. This raises the fuel suction off of the bottom of the tank. Then there is much less chance of the fuel flow being stopped by a bug or something. You also leave the dirt and water behind.

 

[CalG]

Are there really fuel tank supply fittings without screens?

Every motorcycle tank fitting has one. Seems deficient.

 

[k0ua]

I would want to be sure it was fuel and not electrical. I would buy and install one of those cheap digital voltmeters on the fuel solenoid so I could watch it when the intermittent occurred to determine if it lost electrical power to actuate the fuel solenoid or do we really have a fuel starvation problem.

 

[TnAndy]

Are there really fuel tank supply fittings without screens?

Every motorcycle tank fitting has one. Seems deficient.

Actually IS deficient ! Would have cost an extra buck or so, so leave it off...... one of these type things would do the trick....

 

[TnAndy]

I would want to be sure it was fuel and not electrical. I would buy and install one of those cheap digital voltmeters on the fuel solenoid so I could watch it when the intermittent occurred to determine if it lost electrical power to actuate the fuel solenoid or do we really have a fuel starvation problem.

One of these at $3 from Harbor Freight will do the trick. It's either electrical or fuel starvation, but my money is on fuel. Quick glance at the primary filter bowl, if a clear bowl, will tell. You just have to be quick to look before it fills back up.