Montana 4340 losing power

   / Montana 4340 losing power #1  


New member
Sep 20, 2022
Montana 4340C
For those that have Montana tractors an issue can be that they slowly start to lose power and eventually get to where they will only idle. After waiting several days the tractor might start up and idle up fine but within 5 - 10 minutes the RPMs will slowing start dropping off. The first thoughts are either starving for fuel or sucking air. After you eliminate the obvious, replace old fuel lines, potentially clean the fuel tank, and replace the fuel filter, the injector pump is next (extremely expensive). What is not commonly known is that the injector pump inlet has another fuel filter that apparently few know about. The inlet connection consists of a banjo fitting. Remove the banjo fitting and then the connector beneath it. You will have to meticulously fish out the spring and then the plunger assembly and then you will see the top of a plastic filter. Carefully remove the filter and with it will likely come the piston assembly. The problem is very likely that this inlet fuel filter is clogged. Blow it out with air and put everything back, prime to eliminate air and chances are the tractor will spring back to life. Good luck!
   / Montana 4340 losing power #2  
It sounds like your explaning the inlet filter clean out in a Delphi injection pump..
Once u remove the inlet nut..
U can use a pair of needle nose pliers to remove the hold down spring..
THEN, u can use a pocket screwdriver to hold down “the guts”.. while using a 90* pick (scribe) to fish out the filter..which lives on the outside of the hole..
THIS WAY, u don’t have to worry about losing or dropping any springs or pistons that live in the regulator..
   / Montana 4340 losing power
  • Thread Starter
You are correct that this is a Delphi injection pump. The main problem is that after spending 2 weeks talking to so-called tractor experts and mechanics along with looking up information on the internet no one was aware that the inlet filter even existed. It was only after I did a word search for "filter" across the entire tractor parts manual that I stumbled across this additional filter. I did try to minimize taking out unnecessary parts but trying to do all of this and working around the loader frame and then finding that the filter was stuck was a challenge. I didn't find that there was enough room for the pick that I had so a bent paper clip had to do. A learning experience but I was able to save several thousand dollars because all of the mechanics wanted to disassemble and clean the entire fuel system and replace the injector pump at a cost of $1,500 plus labor.
   / Montana 4340 losing power #4  
I hope u r cleaning out your fuel tank and r going to change your filters 2x a year.??
   / Montana 4340 losing power
  • Thread Starter
I inherited the tractor and am having to play catch up. I have already replaced lines, dropped the fuel tank and cleaned it, and will replace the filter regularly moving forward. The tractor is not used a great deal and outside of changing the oil there was no maintenance performed until I got it. To make matters worse, there are not a lot of people that know about or are willing to work on Montana tractors anymore. Making the best out of a bad situation.
   / Montana 4340 losing power
  • Thread Starter
I do have a question for you. In speaking with a couple of Montana mechanics they said that they thought that the Delphi pump had an oil plug and that I needed to check the oil. I have seen one thread where the 3240 needed to have oil put in the injector pump but I can find no where that this is part of the 4340. What can you tell me?
   / Montana 4340 losing power #8  
If we’re talking about the Delphi pump as above.
U need to find better mechanics..
The inj pump is fuel oil lubricated.. not engine oil lubricated..
   / Montana 4340 losing power
  • Thread Starter
That was my guess but wanted to ask. Thanks.
   / Montana 4340 losing power #10  
Thanks to you both, just got the same tractor ['06] w/ loader and was maintained. With all the difficulty in finding good Montana info, bookmarking this info into my library.

Any other sources of viable Montana info would be appreciated.

Montana 4340 in Abilene Texas