My BX let me down today....

r0GuE · Jan 17, 2004

This morning I went out to the shed to get my BX for some light snow removal. I have about 3 ½ inches, and I wanted to hit my neighbors too. I held the glow plugs (and therefore the fuel pump) for 30 seconds and gave it a shot. No start. I tried and tried and while it seemed like it was close… no cigar. It produced huge amounts of black smoke. I have about ¼ tank of conditioned fuel (I doubt I have the mix right as the container only gives directions for mixing with 100 gallons of diesel). It was cold today, but not ridiculous, perhaps 25 (but it had been very very very cold last week. The fuel in my 5 gallon can is gelled and wont get through the screen. Gee I should have treated that too.

I finally got it started tonight, but I’m wondering what was wrong. Given that it turned over and smoke but would not start, what is your vote? My guesses for possibilities are:

Too cold (it was before but not that cold when I tried to start it and it did turn over.

Weak Battery (again, it was turning over, but perhaps not heating the plugs enough?)

Gelled fuel (I did finally get it started and it ran fine once I did).

Flooded (could I have flooded it by holding the glow plugs / fuel pump on for 30ish seconds?)

I’m very curious, but not proficient enough with diesel (or any other kind) engines.

Thanks!

JDgreen227 · Jan 17, 2004

I honestly don't know if it's possible to flood a diesel engine, but 30 seconds sounds like a long time to use the glow plugs at 25 degrees. I have only used the air intake preheat system on my JD one time, the factory suggests 10-15 seconds at zero degrees. I used the preheat for five seconds at six above zero the other day and it fired right up.

I would advise you not to let your fuel tank get down to a quarter full when the weather is really cold. Condensation is a real problem if you combine cold temperatures with a low fuel supply. If your engine cranked fast enough it's a safe bet your fuel supply was at fault, not the battery. I have never seen heavy black smoke from a diesel tractor at startup, fine black smoke or grey smoke, yes.

If you flood an older gasoline engine you are supposed to hold the throttle down and crank the engine, but I don't know if that advice applies to a diesel engine. Anybody else know about that one?

Junkman · Jan 18, 2004

If you touch the accelerator when starting a diesel engine, you can flood the cylinders. Most are started by leaving the accelerator in its base position. As for the fuel, it was probably just gelled. Contrary to popular opinion, the winter air is very dry and condensation is not as much a problem in the tank as it would be on a humid day in the summer. Keeping the fuel tank full in the winter is an old wives tale as far as I am concerned. The reasoning is flawed about condensation. One reason to keep the tank full in the winter is the same as in the summer.... You don't want to run out of fuel at any time. I fill my tank every time I put it away. That way, I know that I will never run low. Get a block heater and you will not have any problems. I am running summer blend (home heating oil) in my BX22 and have not had any problems. A couple of evenings ago, it was -11 and I had the tractor out for about an hour moving some things around. Never had a problem with the fuel. If I do have a problem, I will switch to a winter blend, but I also use Power Service in the fuel... Seems to do the trick for me.... /forums/images/graemlins/smile.gif
One other thought came to mind.... if you have a gasoline powered car and you let the fuel get low, there can be water at the bottom of the tank that will be picked up by the fuel pick up that floats just below the surface of the fuel. This is only on cars..... on tractors, the fuel is taken off of the bottom of the tank, so if you get water into the tank, you will know about it quickly.....

JDgreen227 · Jan 18, 2004

Junkman,

Good info in your post, it's amazing how much I can learn from the other members here on TBN. I cannot recall a time I logged on and DIDN'T learn something new.

rbarker · Jan 18, 2004

( I finally got it started tonight, but I’m wondering what was wrong. Given that it turned over and smoke but would not start, what is your vote? )

I went through this last week with the same symptoms only colder conditions. Warming the tractor solved the problem and I will be installing the block heater when I get a chance. I was unable to determine whether it was fuel related or just cold related.

Junkman · Jan 18, 2004

( I finally got it started tonight, but I’m wondering what was wrong. Given that it turned over and smoke but would not start, what is your vote?

............ I was unable to determine whether it was fuel related or just cold related. )

It is both ........ They are both seasonally related.... /forums/images/graemlins/grin.gif

RalphVa · Jan 18, 2004

It's very important to open the throttle about 1/4 to 1/3 when starting a very cold engine. Did you have the throttle set at idle?

On my old Benzes, they have a hand-set fast idle on the throttle that you'd better use, else you might let up too much on the foot throttle and kill the engine. In very cold weather, you HAVE to push the foot throttle down about 1/3 way, maybe as much as half. The hand throttle is just insurance to be sure you don't let up too much once it starts.

Fuel gelling is also a problem. I'd put a light bulb next to the fuel filter, use an anti-gel additive or put 1/3 to 1/2 kerosene in the fuel.

I don't think it's possible to "flood" a diesel engine. Never done it in driving my two Benzes about 250k miles now. Actually, the ONLY times they've ever failed to start, as long as the battery turned the engine over a couple turns, is when I had a radially-cracked fuel line that caused air to be sucked into the line into the suction of the low pressure pump. (Well, there was a bit of cranking on this newer Benz after it was stored for 4 1/2 years. It started though.)

I've driven high mileage rental diesels that wouldn't start, probably from low compression from the high mileage and rough treatment.

Ralph

art · Jan 18, 2004

To flood a diesel Is not really possible but yet it is. A diesel runs by heat of compression causing an explosion. If you can't get enough heat you will just wash the cylinders with fuel. The more cold or unperfect fuel blasts the less chance you have of gaining the heat of a perfect explosion. I'd be running a block heater if I was you. It is a cheap insurance policy for success.

Junkman · Jan 19, 2004

Ralph,
I have owned Mercedes diesels since 1966 until 1995. I know what you are talking about with the small knob that you would twist to increase the engine speed. This knob would only increase it about 300 - 400 RPM. Just enough to keep it running AFTER you got it started. A lot has changed in diesel engines and what you did with your engines then isn't what is recommended today. You can flood a diesel engine and it isn't good to race an engine when it is cold, gas or diesel. Back then, Mercedes recommended that you add up to 10% gasoline to the fuel for winter driving and also recommended to use a quart of Dextron ATF in the fuel to clean the injectors. All that advise is no longer given and is considered bad for modern engines. What you did with a Mercedes that was manufactured many years ago isn't good advise for a Kubota manufactured to todays standards. Even the Mercedes diesels of today are a world apart from the Mercedes diesels of the 1980's. The particle traps are gone and they run cleaner and quieter. Times have changed to say the least. I remember having pulling out the glow plug rod and watching the "glow plug" that was mounted in the dash get red hot indicating that the engine glow plugs were energized. That technology is as ancient as can be. Today we turn a key and hold it for 10 - 15 seconds. Back then, it was for a minute at least and it would take a couple of tries to get them running.

Junkman · Jan 20, 2004

Art...... the concept of how a diesel engine works is one that is not easily understood by many people. I have found that the best way to show them that the fuel isn't ignited except under certain conditions is to put some diesel fuel into a container and then throw a lit match into it. It will not burn! It has to be atomized and have air compressed to create heat before it will combust. This is a totally alien concept to people that have grown up around gasoline and gasoline engines. If when cranking a diesel engine you depress the accelerator and feed more fuel into the cylinders, that fuel will pool on the top of the piston and will actually inhibit the combustion process and result in what you describe.
A good illustration can be found at this web page .