Kubota 300 Issue

[RogerAS]

Damaged or loose sealing washers are one of the most important things to look for when inspecting and servicing a fuel system.

Try the test that I wrote earlier once you have checked the sealing washers.

Henry

I'll make a run to the parts store after work tomorrow with inlet fitting in hand. I'll get all new  pressure washers. I'm going to buy some "brand new" fuel line for both the feed and return lines. I wish there was a diesel proof clear line so I could see any air getting into the system! My Jerry can has a fitting where I used to run the return at the very top of the tank, and I'll place a peanut butter jar there and start the engine. If it passes the no bubble test I'll put it back to returning to the main tank. I find it doubtful that this is THE issue as the engine ran great in the current configuration for 4 years, but I'm willing to try anything at this point.

RS

[vdubnut62]

I have an old International tractor that once did the same tricks. What I finally found was a screen 'way down hidden under the fuel intake fitting in the injector pump. It just about made me replace the injector pump before I discovered it because it had 9000 plus hours on it, and I didn't think it could possibly still be in good shape.
15 years later , it's still running on the same old CAV pump
How all the crud  I found in the little plastic screen got past the filters, I will never know.  Maybe it was algae and grew in there?
Ron

[rl71459]

My Thermo King C201 (isuzu) drove me nuts due to a plugged inlet strainer screen in the lift pump banjo fitting... I didnt know it existed until then.

Rob

[Lloyd]

Also check to make sure the fuel supply line isn't collapsing...I've seen that happen with the same symptoms...It sounds as if air is in the the suctions side...filter...olive...copper washer...or a cracked fitting...I have seen this happen with the same symptoms.

Lloyd

Llyod,

You may be on to something here. When I removed the inlet fitting I noticed the copper washer between the inlet fitting and the injector pump was distorted a little bit. I will replace that little devil and give it another try.

Thanks,

RS

Number 1 rule in diesel...is never to re-use the sealing washers...they're cheap and should be replaced, when ever  and injector/fitting has been apart.

Also...check your fitting at the tank suction...maybe it's getting old.

Lloyd

[vdubnut62]

Generally, when diesels have a fuel (or air due to bad sealing washers) leak on the suction side, they will not start right back up until the fuel system is
bled of all the air.  Sounds like a blockage to me. Could "something" be lurking in the fuel tank and blocking the pickup from time to time? That can also cause a fuel line to collapse, I have had that happen too.
Just my .02
Ron

[RogerAS]

Update,

I just finished the work to bring the fuel system back to par.

Since I am now employing the jerry can for the Honda gas engine I had to "borrow" the tank from my ZZ Briggs.

After making sure the tank was still clean, which it was, I fitted brand new hoses, clamps, both sediment and inline filters, new copper "banjo" washers. New fuel bought this morning from a different place than usual. The new/old tank is about 6" higher than the outlet for the jerry can, mostly because it was light enough to position just so and still fill easily.

The engine has been running for 45 minutes with no load, only the cooling fan driven, at full throttle, and for these engines that's about 2,200 RPM. I did the bubble test on the bypass from the injector and this is NOT happening.

The engine seems to be running steady and true with no bogging or misses. It started on the second or third rotation and came right up to speed. The usual clatter of the diesel ignition is there, but it always has been. Even though this is a water cooled engine the mechanical end is still kinda noisy. I don't hear any valve clatter or tappet rattle. The lower end is not rumbling.

I plan on running the engine for several hours, as the tank from my old Briggs seems to be about 1.5 gal and see if anything happens. If the engine doesn't have one of its fits that is.

If the engine still seems to be happy after this long test run I'll mount the big alternator back, add more fuel, and see if this is indeed the issue. If the engine then stumbles at least I can rest easy that it isn't NOW a fuel delivery problem.

I am beginning to suspect that my fuel went bad on me. Here in Arkansas from late spring until mid summer we get most of our power from sun, then the heat demands air conditioning. We rarely have to run the Kubota. I filled my tank back at the end of March and don't remember adding any until the first of June. If my fuel source is not top notch to start off letting it sit for months couldn't help. I also suspect my fuel lines may have been leaching gunk as post removal inspection showed some slime, not very much at all really, on the walls.

When I opened the prime cock the fuel gurgled several big bubbles and smoothed out just like its supposed to. I caught the expelled fuel in a peanut butter jar to make sure it was still clean, and it was.

Wish me, and the old 300, luck, and thanks very much for all the sound advice offered so freely from all of you. Really!

R

[RogerAS]

Update #2,

Well, since the engine seemed to be doing great after 2+ hours of running I replaced the big alt and started putting a load on. I cranked it up to 40 amps, turned on the AC and waiting to see what happens. Yep, it's sure hot and humid here today and standing over a running engine is sweaty stuff.

It looks like the engine burned about 1/2 to 1/3 cup of fuel under this no-load run.

The oil pressure, according to a mechanical gauge, reads 36LBS and steady.

The water temp, after running for 15 minutes with this load, settled out at 185°F, again according to a mechanical meter.

I did run the load well past my C-20 rate, 70+ Amps, for a few minutes and besides the black smoke and a little climb in temp the engine didn't complain too much at all. I suspect there was just a fuel delivery/quality issue that has now been resolved.

I'll repost another update after a few hours of running under load. The fingers are still fully crossed!

R

[Apogee]

Good job Roger!

Glad you found the problem...

Congrats,

Steve 

[RogerAS]

Steve,

I realize I changed far too many parts of the fuel system to be able, in hindsight, to pinpoint what the issue was.

Yes, I know the fuel system was now at fault, and or I had a bacterial/fungal infection in my fuel, and or the lines were rotting, and or the copper sealing washers were bad. I feel ashamed of myself for being so cheap about this stuff. The new fuel line is diesel/biofuel rated and NOT cheap. The old line wasn't diesel rated and WAS cheap.

The gasoline I have burned in the past couple weeks, not to mention stress hours, easily exceed the effort and cost of doing all this back in spring in ANTICIPATION of running hard during these summer months. One would think this would be a much higher priority. Turkey season CAN cause problems! Man do I feel lousy.

Oh well, I looked into parts to re-ring/mains/head/pump and I may order them so I can rest easy about those hours on this engine when the Army owned it. I bet I could get the engine apart and back together in less than a day. If the old beast will live 'til fall, when it's cooler outside, I may just spruce her up.

Thanks again everyone.

R

[Lloyd]

R,

Glad to here everything is now up to snuff....One thing I learned long ago....it's way cheaper to do it right the first time...as opposed to doing it twice...it near doubles the parts costs, and for sure doubles the labor cost, when the low road is taken...

As a pilot, and a marine skipper, I can tell you the last thing I want is a mechanical failure in-route...but it also carries over for everything I do, from a simple home remodel to what ever...bc I HATE to re-do my work.

Lloyd

[RogerAS]

Update #3,

The engine (300 series) is clicking along just fine, back to sipping fuel, not burning a detectable level of lube and running like a clock. I couldn't be happier.

I'm driving a large frame LN (200 AMP) at a constant, but adjustable, rate. Right now The engine is driving about 20 amps into my 1320 AH 12V bank. The Air Conditioner, this laptop, our 32" CRT type TV and all the other loads come up to about 18 amps drain. Yes the AC unit is very SMALL, but so is our house.

I still feel this engine is getting a little long in the tooth, and I'm thinking very hard about ordering the parts to just freshen it up a mite. I have observed the engine seems to puff a little smoke, mainly white after a burst of black until it warms up. Have the valve guides begun to leak lube, or maybe the seats? Ideas?

Also I need to figure out a tach for this engine. I could attach a small/tiny neo-magnet from a CD drive to the flywheel and read that, but is there a better way to monitor this direct injected engine for RPM? I've not seen much out there for this type engine. I've read about using bicycle computers and don't know if that would work here. I'm concerned with heat/vibration/chemical exposure, thus my mechanical gauge set. Speedometer from a car driven off small belt idler? Ideas?

RF

[Henry W]

Here is a tach that is very easy to install.

http://www.tinytach.com/tinytach/diesel.php

Henry