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paulz
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# Posted: 18 Sep 2025 04:14pm
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Trying to get my old backhoe going. Wont start. No primer by the filter i can see. Thought maybe Lp but read bad idea…
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toyota_mdt_tech
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# Posted: 18 Sep 2025 08:39pm
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Brake cleaner in air inlet, see if it will pop.
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travellerw
Member
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# Posted: 18 Sep 2025 11:58pm
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Modernish diesels will usually self bleed if there is air in the lines. However it can take a whole poopton of cranking.
I usually crack the line at the injector and crank until liquid diesel comes out. Do that for each injector. Then see if she will pop off.
If you don't see diesel at the injectors, then you got a feed problem. Usually plugged line, filter or tank pickup.
I really avoid starting fluid if I can. Being dry its hard on things. There are also some diesels that will be damaged with it (I have 2 generators right now that had busted rings from starting fluid). However, I don't think a hoe would be too bothered by it as a last resort.
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toyota_mdt_tech
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# Posted: 19 Sep 2025 07:45am - Edited by: toyota_mdt_tech
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Quoting: travellerw I really avoid starting fluid if I can
Its why I mention brake cleaner. It was just to see if it would pop as mentioned in my reply.
If it did pop, then you know fuel issue. Next plan was to inject a small amount of air into the fuel tank, maybe 5 lbs or so with a line at injector pump cracked open. Watch for fuel to leak out. Close off, shut compressed air off.
This can be done with a blow nozzle and a shop rag around filler neck and blow nozzle tip. Saves the starter from a poopton of cranking.
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paulz
Member
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# Posted: 19 Sep 2025 01:13pm
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Thanks guys. Will try the brake clean, but the fuel filter o-ring broke so will be a few days.
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Brettny
Member
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# Posted: 19 Sep 2025 06:48pm
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Just use staring fluid. If I remember it's no new machine.
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DRP
Member
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# Posted: 19 Sep 2025 08:12pm
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I usually wrap a rag around a blow nozzle and gently pressurize the tank at the fill nozzle while someone cranks it over, you want 5 psi shoving the fuel up the line not 100!
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paulz
Member
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# Posted: 26 Sep 2025 07:27pm
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Quoting: DRP I usually wrap a rag around a blow nozzle and gently pressurize the tank at the fill nozzle while someone cranks it over, you want 5 psi shoving the fuel up the line not 100!
Ill try that. Still no start today. Perkins 3 banger. Ive bled the injector pump, primed the fuel pump.. cant get to the nozzles, they're under the fuel tank. Squirt of brake clean down the air cleaner tube does nothing. A shot of starting fluid and it pops once.
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gcrank1
Member
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# Posted: 27 Sep 2025 11:18am
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On my dad's old Ford 5000 if you ran it dry you had to crank like forever to get it to go
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toyota_mdt_tech
Member
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# Posted: 29 Sep 2025 08:26pm
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Quoting: DRP I usually wrap a rag around a blow nozzle and gently pressurize the tank at the fill nozzle while someone cranks it over, you want 5 psi shoving the fuel up the line not 100!
Must be an echo in here. 
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paulz
Member
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# Posted: 6 Oct 2025 09:29am
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Still fighting this tractor diesel. Tried the tank pressure and 100 other things. At the point now it seems as if the pressure rack inside the Lucas CAV pump may be stuck, gummed with varnish inside. More work and testing, I just need to be able to ground clean around my well shack before winter.
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travellerw
Member
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# Posted: 6 Oct 2025 10:24am
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Quoting: paulz Still fighting this tractor diesel. Tried the tank pressure and 100 other things. At the point now it seems as if the pressure rack inside the Lucas CAV pump may be stuck, gummed with varnish inside. More work and testing, I just need to be able to ground clean around my well shack before winter.
Remember, just 3 things to run. Air, Compression and fuel. You must have all 3.
Since it will pop off with starting fluid, then you most likely have compression and air. So your idea of being gummed up or clogged is probably sound.
I have a small diesel generator that was in the same boat. I had to take the entire fuel system apart (from the tank to the injector) and clean it. Good old fashioned carb clean worked very well. Unfortunately, that is getting hard to find as most have switched to just acetone as an ingredient.
I hope you don't have to go that extreme on yours (my generator had sat untouched for at least 5 years). Hopefully its just the rack.
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DRP
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# Posted: 6 Oct 2025 06:57pm
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Sometimes you run it on ether for long enough to get it to loosen up and take diesel. If you do that barely keep it running, there is a lot of head gasket oomph in ether.
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paulz
Member
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# Posted: 6 Oct 2025 07:59pm
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It wont do more tan an occasional pop on ether, thats a bit scary. Shoot a lot in it does nothing.
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DRP
Member
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# Posted: 7 Oct 2025 07:37am
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I'd check compression at that point.
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paulz
Member
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# Posted: 7 Oct 2025 08:22am
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How?
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travellerw
Member
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# Posted: 7 Oct 2025 11:17pm - Edited by: travellerw
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You need a diesel compression tester (about $80 on Amazon). It involves taking the injectors out and installing the tester in the hole.
However, if you are going that far, I would bleed at the injectors first. You crack the fastener above the bleed off pipe for 1 injector, then crank over till you see raw fuel squirting out. Tighten it back up and repeat for each cylinder (you have now confirmed good diesel flow up to the injector). Then see if she will fire.
If you get no raw fuel, then you have confirmed a block somewhere.
If she doesn't fire (and you had good fuel to the injector), then the next logical step is a compression test!
I really don't think its compression as you had this running in the past. If it was running, then parked for a period and now won't run, the most likely cause is fuel.
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gcrank1
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# Posted: 8 Oct 2025 09:28am
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I had to disassemble an old aux shop oil burner heater 'carb' waayyy back, it just wouldnt flow. The whole thing was a gummy mess inside from sitting for ? years. I suspect the same thing happens in a diesel engine system. Might even be worse as a pump is trying to force fuel through and keeps compacting the gummies?
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