B2100 Almost Impossible to Start

[petenpole]

Good morning and I have a 2 fold q1uestion and wondering if they are related.

My 2100 has 801 hours on it and the previous owner was not great about its ongoing maintenance. I have cleaned the fuel filter and its clean as a whistle, the air cleaner is out (only while in my shop and I do diagnostics). The engine shows no signs of being molested or apart in its life. Whe3n the engine is running after being warmed up the only time I see any exhaust smoke is when making a hard turn with the mower deck engaged and it is not excessive. The tractor seems to have good power for mowing and use in 4WD with mower engaged. I can maintain about 2450 RPM when the mid PTO is engaged.

The tractor shows approx 7 ohms of resistance on the jumper strip for the glow plugs to ground. With the ignition switch turned to glow plug warm up and the glow plugs attached I only register 9.6-9.8 VDC on a good charged battery.

First: It takes 3-5 minutes of cranking to get the tractor to even start to act like it will run and that is only with the throttle in the idle position. And it is belching black smoke like mad ( i know black smoke on startup can be normal) but this seems almost excessive. Sometimes the cranking is so prolonged, I have to use jumper cables to get it to finish cranking to start. If i shut the tractor off after it has been run 30 minutes to use restroom or get a drink, it takes even longer to get it restarted.

Second: I have now started leaving the tractor at an idle when i need to get off, and when I do the blow by on the left side of the engine from the breather tube that appears to be going to the valve cover is voluminous. Its a not wet to the touch and not black in color just gray and its unreal how much is expelled through the breather tube.

I am looking for advice, are these 2 issues related or stand alone issues? Should I be looking at a valve adjustment ( if even possible)? Is this an issue related to the injectors or glow plugs? I do have the WSM for the tractor, but before I tear it half apart I would like some expert opinions as to where to start.

Many thanks

Bill in NW Missouri

 

[Motion]

As always do as you feel is best. I'd have the battery load checked. Perform a good compression test. Test each glow separately.

 

[petenpole]

As always do as you feel is best. I'd have the battery load checked. Perform a good compression test. Test each glow separately.

Thank you for the suggestions, as most of my life has been repairing Gas engines, do we simply pull the injectors for a compression test and does it require any unusual compression tester or will any work?

 

[Roadworthy]

The glow plugs are wired in parallel. You can't check them all at once with an ohmmeter. If only one is good you'll get continuity. Your glow plug voltage is about right. Many run at 10.5 volts, they are not really a twelve volt device. The tractor will have some sort of voltage drop. Black smoke is frequently caused by a blocked airway - too rich a mixture. If your air filter is clean check for other blockages between the air filter and the intake manifold.

 

[Motion]

I believe it's easier to do a compression test using the glow plug holes, if you pull the injectors there's sealing rings and heat cups to deal with. I'd suggest pulling the glow plugs (measure ohms) and measure the diameter, pitch and length, then purchase the correct size which may come in a set, some set are very expensive, I prefer to have a good gauge and purchase adapters as needed. If it doesn't the you need a 1,000# gauge and a hose to connect, make sure you have a good battery, record your readings and see what your WSM calls for. I can't speak for anyone else but when buying a used piece of equipment I don't care what the PO or dealer says I automatically change the filters, oil, fluids, coolant, etc. I also like to do a base line compression test weather it's gas or diesel and record for future use. And if easy to achieve get real oil pressure. When removing pieces /parts from multiple cylinder engines mark/number them. Good luck

 

[kubotafreak]

Bad fuel? Repetitive cranking can cause the billowing of black smoke. Sounds like low compression if you have confirmed plugs are getting hot. Pull the oil cap when its running to see how much blow by is in the valve cover. It should not look like a steam locomotive.

 

[petenpole]

Taking the sage advice, I have gotten 2 glow plugs out and they both glow red battery voltage applied. The 3rd is being a challenge but it will get pulled and checked.

If all 3 glow red I will go find the appropriate compression guage and fittings and go from there next

 

[petenpole]

Bad fuel? Repetitive cranking can cause the billowing of black smoke. Sounds like low compression if you have confirmed plugs are getting hot. Pull the oil cap when its running to see how much blow by is in the valve cover. It should not look like a steam locomotive.

When Warm and idling the breather hose is puffing a lot of exhaust not black or blue.

 

[Motion]

Glowing red that's one sure way to prove (LOL), ohm meters work very well and you have the specs. to go by. Don't leave them energized too long they'll burn up. Cranking 3-5 minutes will surly test the battery not only are you damaging the starter but the glow pugs are cooking (at least two) not to mention dumping fuel on top of the rings. I recommend stopping until you can preform a compression test, at the very least put your finger on top the glow plug hole and spin it over (you shouldn't be able to but don't put your finger in the hole). As cheap as glow plugs are I'd buy all three.

 

[Russell King]

Doubt that glow plugs are the issue if it is hard to start after running for 30 minutes. By that time it should be warmed up enough to start easily.

But since you have them out they are fairly cheap to replace unless your’s are unusually higher priced.

Check the compression as already suggested and save time diagnosing probably phantom issues.

 

[whitetiger]

Taking the sage advice, I have gotten 2 glow plugs out and they both glow red battery voltage applied. The 3rd is being a challenge but it will get pulled and checked.

If all 3 glow red I will go find the appropriate compression guage and fittings and go from there next

There should be the proper test procedure for glow plugs in your WSM

 

[petenpole]

all 3l Glow Plugs glowed after about 4 seconds of 12V. So I again drained the fuel sump, and added agriculture Diesel fuel to the tank to dilute some of the auto diesel i had in there. It didnt take as long to start though it didn't start easily. And yes I had it hooked up to a strong battery. I will add more ag diesel if there is a difference in diesel fuel to see if that helps before i do a compression test.

 

[DaveFromMi]

Sounds like lack of compression if there is huge blow by from the breather tube. Compression is needed to ignite the air fuel mixture.
What does the motor oil look like? If you have piston ring blow by, the oil will be dirty.

 

[jimmyjoe]

all 3l Glow Plugs glowed after about 4 seconds of 12V. So I again drained the fuel sump, and added agriculture Diesel fuel to the tank to dilute some of the auto diesel i had in there. It didnt take as long to start though it didn't start easily. And yes I had it hooked up to a strong battery. I will add more ag diesel if there is a difference in diesel fuel to see if that helps before i do a compression test.

auto diesel and ag diesel are the same except the color.

 

[petenpole]

After exhausting all the suggestions and the limited knowlege I have on Diesels I took the 2100 to the dealer. And.....

All 3 cylinders have less than 150Lbs of compression.

So either I junk it out for parts or locate a good used engine and learn how to split a Kubota and install another engine.

Now i make some hard decisions.

 

[Motion]

At the very least check the valve clearances, run a another compression test. If it's still low then pull the head, check the cylinders, give the head a good going over, place a straight edge and confirm the pistons are all coming up the same amount (bent rods). Get a WSM. It's either the rings, pistons ,head/valves or head gasket. If the bottom end is good have the head checked by a shop. If it's the bottom end then manual will let you know if the pan can come off in place. Take and post pictures. If you're going to own diesels you as well invest in a compression tester. 800 hours it's just getting broke in. Don't throw in the towel with knowledge comes options. I do say it odd that all three have the same low compression. You may have washed the cylinders you won't know until you look. You must have other grass cutting machines, you've been down for over two months. Just my .02

 

[petenpole]

At the very least check the valve clearances, run a another compression test. If it's still low then pull the head, check the cylinders, give the head a good going over, place a straight edge and confirm the pistons are all coming up the same amount (bent rods). Get a WSM. It's either the rings, pistons ,head/valves or head gasket. If the bottom end is good have the head checked by a shop. If it's the bottom end then manual will let you know if the pan can come off in place. Take and post pictures. If you're going to own diesels you as well invest in a compression tester. 800 hours it's just getting broke in. Don't throw in the towel with knowledge comes options. I do say it odd that all three have the same low compression. You may have washed the cylinders you won't know until you look. You must have other grass cutting machines, you've been down for over two months. Just my .02

Yes I have other machines to mow with and there is a part of me that says this fall and winter I am going to become a diesel mechanic, a gas engine doesnt scare me its just the unknown on this beast. But I have tools and a manual so I can start with pulling the head and find what lies ahead

 

[JerryMT]

You said " I have cleaned the fuel filter and its clean as a whistle, ...". How did you clean the filter? I have never seen a fuel filter element that could be" cleaned". Maybe they exist and i have just not seen one. I'd recommend you replace the fuel filter and check the fuel delivery to the pump. make sure the return to tank line is clear.

Diesels need fuel at the right time, airflow and compression to heat the fuel air mixture to its ignition point and produce power. Make sure the intake manifold is clear ( no mouse nest or mud daubers) that the fuel delivery to the injection pump (IP) is available in copious amounts, and the compression is sufficient ( greater than 350-375 psig). If you have had the fuel delivery system apart, follow the OEM's bleeding instructions. If you have the requisite fuel. air and compression, and your the engine is in reasonable mechanical condition, it will start.

 

[Motion]

"Nothing is to be feared only understood"

 

[petenpole]

You said " I have cleaned the fuel filter and its clean as a whistle, ...". How did you clean the filter? I have never seen a fuel filter element that could be" cleaned".

I blew it out multiple times and eventually even replaced it.