1520 again running poor

So, I guess I have some sort of gremlin living in my fuel system. A couple weeks ago it lost power and the engine slowed until it barely ran. I discovered that my fuel filter was clogged up with nasty sludge from my fuel tank. So I drained the tank, changed the filter, and added new fuel with biocide and anti gel additive. All was well for a couple weeks and now it is doing the same thing. It will lose power and run terrible until it eventually dies. I can usually start it up in a few min and it will run okay for a few min and do the same thing again. The glass bowl under the fuel filter has some sludge in it but its not full of it. I figured I would change the fuel filter again (cheap insurance) and see how it's runs. Is there any way to clean out the injection pump without disassembly? Should I just run some sort of fancy fuel system cleaner? What would be the next step in this process? It was -15 this morning, but I am using winter blend fuel and an anti gel additive and the coolant heater is plugged in... So I doubt it is gelled up.

What is the make/model of injection pump your engine has? That can make a difference on troubleshooting your problem.

If there is some sludge in the bowl, I expect there is some in the filter media as well. Change the filter. Then follow through on the pump test which has been suggested.

To Dieseltech's asking what pump you have; it appears there were a couple different pumps used. If you don't know which injection pump you have, post a picture of it. looking at past posts you have made about this problem, it has been suggested to you a number of times in the past few months to loosen the small cover on the side (if it has one) of the injection pump and try running it with fuel leaking out. If it runs that way, but not with the cover tight, it is a sign the pump needs a rebuild. I don't see that you have posted a reply to the results of doing that in the past, if you did do that test.

It is a stanadyne pump. Last time I posted an issue dieseltech told me to loosen the side cover and if it ran better then the pump needs attention. I did this and it did not run better, however after changing the filter it was running good. I just wonder if sediment or sludge is in the injection pump. Here is a picture of the pump....

Also, sorry I did not post the results to this test. I try to post the results or solution to the problem so that folks in the future can read about it if they are experiencing the same problems. I get busy sometimes and forget. A "squirrel" moment....

(quoted from post at 19:09:05 01/01/22) Also, sorry I did not post the results to this test. I try to post the results or solution to the problem so that folks in the future can read about it if they are experiencing the same problems. I get busy sometimes and forget. A "squirrel" moment....

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Thanks for providing that, without the answer one doesn't know if you tried it or not. Since you say it didn't change with the cover loose, that answers that question. I would say change the filter again. If the filter is doing its job the crap isn't reaching the injection pump. There should be a cleanable screen in the inlet of the pump you can check. Remove the inlet line and it will be under the hex plug the inlet elbow is screwed into.

I will definitely check that screen next week. I REALLY wanted to do this tomorrow but the local parts store is closed for new years day, so no filter until Monday at the soonest.

(quoted from post at 01:30:56 01/02/22) I will definitely check that screen next week. I REALLY wanted to do this tomorrow but the local parts store is closed for new years day, so no filter until Monday at the soonest.

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You should consider keeping a spare fuel filter, or set of fuel filters, on hand. It would be cheap insurance, especially since you have been having fuel problems with this tractor. Just keep the spares where it is clean and dry. An oil change is generally planned, and you can pick a filter up, fuel filters plug at random times, generally at the wrong time. I keep a complete spare set of filters on hand for my equipment, I can service them when I want and replace the filters I used after.

Did you check to see if
you have good fuel flow
to the transfer pump? You
may have sludge or dirt
in a line or fitting
restricting fuel flow.

Tomorrow I plan on cleaning all of the lines from the tank to the injection pump. I will look for the screen at the pump inlet and clean it. It will get a fresh filter and I will verify there is good flow from the tank petcock. Figure that should cover all my bases. I may even run some fancy fuel system cleaner thru it. I may even loosen that inspection cover on the pump and see what it does, I did it once before but I might as well double check.

(quoted from post at 12:48:56 01/02/22) Tomorrow I plan on cleaning all of the lines from the tank to the injection pump. I will look for the screen at the pump inlet and clean it. It will get a fresh filter and I will verify there is good flow from the tank petcock. Figure that should cover all my bases. I may even run some fancy fuel system cleaner thru it. I may even loosen that inspection cover on the pump and see what it does, I did it once before but I might as well double check.

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Clean the lines, check the tank, change the filter, and use the additives. Keep a screwdriver handy as you use it but wait on opening the cover on the pump until it acts up. If it won't run and loosening the cover lets it run, you have a result. To loosen the cover right along with those other things won't mean much to me. In the past you have posted it ran good after changing the filter and lines. If I was going to do anything around the cover at this time, along with the other items, I would put a clean white rag below the cover and take it clear off and see if any "mouse turds" come out or are resting behind the cover. Another place to check for them is at the check valve in the excess fuel return line at the top of the pump.

The shutoff valve in your tank is supposed to have a standpipe on it inside the tank. It is a pain to do, but you might want to consider completely draining the tank by removing the valve. Clean the bottom of the tank and clean the standpipe and valve while it is out. Just draining through the petcock could leave a couple inches of crud in the tank.

Would a siphon long enough to reach the bottom of the tank pull out the majority of the trash in the tank?

(quoted from post at 22:52:35 01/02/22) Would a siphon long enough to reach the bottom of the tank pull out the majority of the trash in the tank?

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It could or the hole for the fuel gauge sender can be used for a lower access after the fuel level is below it. With the tank empty, blowing air back through the shutoff valve may clear anything built up inside the standpipe, but removal and visually checking it is the only way to tell nothing is stuck inside it causing a restriction. Just my thoughts from dealing with a couple having crap in the tanks.

Well, I said I would report back with results Monday. Well every parts store in town is currently out of my filter, so nothing new to report. Got the part ordered. Also, I ordered a spare as was suggested.