1966 JD450 diesel engine running rough.....?

[little1406]

Greetings Yellow Iron Enthusiasts,

I am a newcomer to your club. My first machine is a 1966 JD450 crawler loader with backhoe attachment. It has 1100 hours so it's not yet worn out. Everything more-or-less works on this machine but it has not received the best maintenance over the years. I found the HLR transmission to be FIVE GALLONS low on fluid....! Amazingly the remaining 3 gallons served to make the thing drive perfectly during the look-see visit and it wasn't until I tried to drive it up onto the trailer, which produced a pronounced tilt, that the lack of fluid made the thing stop moving completely. I've restored the transmission fluid (yes, I'm going to look for the leak) and have been using the machine a little, just trying to get used to it. I've never had anything like this before!!!

The engine starts easily and runs just fine when it's cold. But once it's all warmed up (temp gauge shows mid-range), the engine starts missing and hopping and carrying on like a gas engine with the choke on. I cleaned a couple of pounds of dust out of the air cleaner and it made no difference at all.

I have not looked at the fuel filter(s) yet. The diesel fuel in the tank might be kinda old.

Any ideas?

[LeonardL]

I would change the fuel filter or filters, which ever you have. If this machine has sat for a while, then I would probably go ahead and drain the fuel and clean the tank as well. Also make sure the fuel tank vent is open as insects like to clog them up. Thus your system will pull a vacuum in the tank. You will find it just under the fuel fill cap and is a small round tube that should be easy to see. You can blow it out with compressed air or run a small wire down through it.

[little1406]

Thanks, Leonard.

I bought new fuel filters at the local dealership and found the section in the manual that showed where they are on the right side of the engine.

But when I went to replace them today I found a totally different-looking filter. It's a rectangular glass box held in place by a sortof sheet metal spring clip....!

My 450 is a 1968 model according to the s/n list in the FAQ on this site. Anybody seen that "glass box" fuel filter before?

Scott[/img]

[LeonardL]

Hey Scott,
Yes, the glass filter is a Stanadyne filter and is used largely on later models. So, either some time along the way your machine could have had an engine changed out or someone may have just changed the filter system. Either way you have a simpler filter to change. Just tell your dealer what filter you have and they should exchange it for you.
The filter is held on by a spring holder that goes on over the outside of this filter. This is the sheet metal you mentioned. You simply push in at the top of this holder and lift the end at the same time. It will release the filter and it will practically fall off in your hands.
Ask your dealer about the different procedure for filling the filter and bleeding the air out it. Or... you can find it in the archives here on the forum. If you have trouble finding it here, then bring it back to us on this thread and we will walk you through it. It's really simple and most dealers will help you with the change.

[little1406]

Leonard (and all),

I took off that Stanadyne filter today and was stunned to see what looked like mud oozing out of the inlet port when I tilted the filter. I've never seen such crud in a fuel system before.

With the filter off, I pumped the primer lever on the fuel pump a couple times, which causes fuel to shoot out of that port on the filter mounting surface. Unfortunately, with every squirt of fuel came quite a bit of blackish crud. My fuel system is severely contaminated it seems.

What could this stuff be? How can the fuel pump (which is before the filter) be working properly with all this stuff going through the check valves?

Do I need to remove the fuel tank from the crawler in order to clean it properly?

What about the fuel lines? Blow them out?

Thanks in advance for any advice.

Scott

[shinnery]

Sounds to me like you have diesel algae in your system. Flush the system and add an algaecide to the replacement fuel.
Bryce

[kedorland]

If algae....would the machine have to had biofuel sitting in it to grow?

Kevin

[jtrichard]

No regular fuel gets it

[little1406]

Thanks, Bryce!

Now that you mention it the stuff did look rather like an algae mush.

I had no idea algae could grow in diesel fuel. But it makes sense for this machine. It's seen very little use in recent years and has just been sitting with the tank half full.

BTW, as a physicist, I just love the by-line in your signature!

[LeonardL]

Your tank can be drained on the machine and cleaned. I have used just hot water and bleach to get rid of the Algae. I use a pressure washer to try and really give it a good scrubbing in the bottom of the tank. You may want to consider replacing the transfer pump as just a precaution. You can blow your fuel lines out with compressed air or if you want to, you can fit a Hudson sprayer or some way to flush them out with hot bleach water as well. Then make sure everything is dry before you pour new fuel and fluids in.
I haven't seen this Algae much but it does occur and it seems worse in especially humid climates. The higher humidity causes more condensation in the fuel tanks of mostly diesel equipment. Although I have also seen it in Gasoline before.
The moisture will collect in the bottom of the fuel tanks and the Algae forms in those puddles of water. It then feeds on the diesel fuel. It also seems to form worse in metal tanks rather than the composite or plastic tanks. Also seems to be worse in machines that have sat for a long periods of time.
Sense you found this in your fuel system, you will want to change all of your fluids and filters as this Algae will form in any Petroleum based product. I've seen it in oil pans of engines and in the bottom of transmission cases. It is... some wicked, nasty stuff! Usually after you get it cleaned up and start using your machine it wont return. It is the sitting that gets it started. Any machine that sits for any length of time, is its own worse enemy!

Sense you are new to the forum... I need to warn you that Bryces signature is pretty close to how things are here some times. The Electrons do get disturbed and bothered in many ways!! Some are not so pleasant! I'm not so sure about the trees not being harmed. But is is usually fun and interesting. So, I'll give you a belated Welcome aboard!!

[little1406]

Thanks a lot Leonard,

I like a detailed explanation.

BTW, during all the crawling under the tractor I did to replace my main hydraulic line I found my transmission leak!

The drain plug was barely finger tight! Drip.....drip.....drip.

Yay!

Scott

[digitup2]

Ha I got a 5 gallon pail of algae up here in Canada I bought a 550J LGP down south [not running] that is all that was wrong with it but we don't see that crap up here at all so I kept the pail full of that crap that was in the dozer .He shut it off early fall and by spring it wouldn't run he said I even had to clean out the injector pump as the crap had worked it's way past the filter You can keep that stuff down south .There is even a bacteria that can shut your nitrogen filled rotary laser down to detect it watch on the back side of the glass for what looks like rusty shine that is the culprit and it will leave the most expensive of laser's rotating with no recognition on a receiver had that happen twice to me .Kind of embarrassing having a machine down with a bug .Digitup.

[LeonardL]

Hey Scott,
I'm glad your leak was only a loose plug. As they say... "A blind hog finds an acorn once in a while".

To "digitup"... Up North of the border... We here in the South, meaning South of you anyway... we have all kinds of nice things to keep us occupied in the equipment world. Moisture being the biggest issue and the things that can grow in that moisture.
Then it turns off hot and dry and we fight dust and well... even more dust!! I've never heard of the Nitrogen bug though. Although it doesn't surprise me. We had some Laser issues as well and it makes me wonder if that is what it was.
I have seen these little 350s condense enough water in the steering clutch housings to darn near fill a three pound coffee can. I would chew the operators out for getting the machines off in the water when they hadn't been anywhere near water.
The further South you go the worse it gets. We get the humidity off of the Gulf of Mexico and Scott down in Texas gets more than we do. There are times when you can actually see it hanging in the evening air.
This Algae or what ever it is, loves the moisture it can find in the bottoms of fuel tanks especially. If left alone it can really do some damage. I too have seen it get into the injector pump and really screw things up.
When I worked for the state of MO, we would have Equipment maintenance training for new employees. Mainly just to make sure they were on the same page as the rest of us. I kept a coffee can about half full of this gunk just to pass around. I would give it a little water and new diesel fuel once in a while just to keep it going. Strange stuff to be sure.

[shinnery]

A couple years ago I tried to buy a Dodge CTD pick-up the Feds had down at Aransas National Wildlife Refuge (where the whooping cranes go) and it would not run due to algae. Someone wanted it more than me. Google had lots of info about diesel algae. Ex BSEE and Navy Electronics Technician Radar.
Bryce

[little1406]

I am happy to report that siphoning out all the old diesel+algae from the fuel tank, purging the lines with clean diesel, and replacing the fuel filter has fixed my "engine running rough" problem.

Apparently, the diesel was just starving for fuel due to an algae-clogged filter.

Thanks for all the help, guys.

Back to work.....