HD7GB won’t stay running

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   Dad has a HD7GB crawler loader.  Had the big 3500 6 cyl turbo diesel. 

We rebuilt motor in 2013 and machine has run good since. 

This week, he starts it after about 10 min dies. Will start and dies within seconds.  

So first we change fuel filters. In process find line from tank was split. Thought that was our issue. 

New filters and line on, runs for about 10 min again and then dies.  

Searching online seems like this is a relatively common problem with Roosamaster injection pumps- which this has.  They clog the check valve? Which overpressurizes pump shuts it down

So plan is to blow out return line and remove/clean check valve. Dumb question- where is the check valve?  Is it just the fitting in pump where return line connects? 

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Tiger Joe Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 12 Aug 2012 Location: Pittsburgh Points: 40	Post Options Post Reply Quote Tiger Joe Report Post Thanks(0) Quote Reply Topic: HD7GB won’t stay running Posted: 28 Aug 2025 at 5:47pm
	Dad has a HD7GB crawler loader. Had the big 3500 6 cyl turbo diesel. We rebuilt motor in 2013 and machine has run good since. This week, he starts it after about 10 min dies. Will start and dies within seconds. So first we change fuel filters. In process find line from tank was split. Thought that was our issue. New filters and line on, runs for about 10 min again and then dies. Searching online seems like this is a relatively common problem with Roosamaster injection pumps- which this has. They clog the check valve? Which overpressurizes pump shuts it down So plan is to blow out return line and remove/clean check valve. Dumb question- where is the check valve? Is it just the fitting in pump where return line connects?

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DMiller Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 14 Sep 2009 Location: Hermann, Mo Points: 33938	Post Options Post Reply Quote DMiller Report Post Thanks(0) Quote Reply Posted: 28 Aug 2025 at 6:10pm
	The return fitting atop the Top Cover of the pump. Remove the line and remove the fitting to inspect then clean, then in some not too distant period of time ready yourself to remove said pump for the coupling replacement internally.

Tiger Joe Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 12 Aug 2012 Location: Pittsburgh Points: 40	Post Options Post Reply Quote Tiger Joe Report Post Thanks(0) Quote Reply Posted: 4 hours 58 minutes ago at 9:20am
	Got it running. So looks like someone has been in this before- no check valve on top of pump. Found return line plugged. Again, this appears to be modified from original, it’s metal line that wraps around engine, then turns into rubber hose- then back to original metal somewhere under cab. That hose failed. I was able to blow it out. We are just going to make an entire new hose and put a new valve on the bottom of the tank also.