Jinma 284 fuel system questions

angelugs · Nov 10, 2017

Still troubleshooting the fuel system problem with my 284. Is it possible for the fuel system primer to get clogged up with gunk like the sediment bowl filter and the screened filter in the banjo fitting on the intake side of the primer? If so can the primer unit be removed and cleaned out without having to remove the entire injection pump? I cleaned the screened filter on the intake side of the primer and fuel flows fine from the sediment bowl to the primer. But when I remove the output fuel line and try pumping the primer or turn over the engine, VERY little fuel spurts out. In fact most of the time no fuel is seen. Sometimes a good spurt will occur but mostly none. If the injection pump is bad does that mean the primer is bad too?

thepumpguysc · Nov 10, 2017

Loosen the line at the FRONT of the injection pump.. That's your feed line.. you might just have air trapped in the system.
Loosen that line, pump the hand primer until you get fuel & no air & tighten.
There looks to be another bleeder screw to the left.. Once your get fuel UP TO the injection pump, loosen the bleeder screw to purge all the air out of the fuel gallery.. & tighten.
Next, loosen ALL the lines AT THE INJECTORS & spin the engine until fuel squirts out & tighten..
DONT spin the engine for prolonged periods or you'll burn up the starter.. do it in 10 sec. intervals, let cool for 20 & start again..
Good luck.. IF all else fails, theres a NEW pump on ebay for 400.00.

nepa · Nov 10, 2017

Good answer from thepumpguysc, but are you sure that you took care of all the screens/filters? My eleven year old Jinma 284 had three before the main filter that I entirely ripped out and opted for an inline filter instead that can be changed in a few minutes. But as Bob said, keep that fuel clean and never store fuel in any container that has even a trace of water in it. Good luck.

jacques54 · Nov 10, 2017

Do you clean the screen filtrer IN the hose at the inlet of the priming pump. Clean it open the bowl valve flush the hose the reinstall. Remove the hose from priming pump to the filtrer then try the priming pump. It should pump, unless pump puppet valve stay open by bug sludge.
Make your way with a GOOD flow hose by hose in a pail right To the inlet of fuel pump. Then bleed the system and loosen injectors tubes and crank the engine until fuel squirt beside the nut.
Tight the tube nut then the engine must start. Be sure the STOP is not pulled. (deja vu )
It seem you win the bug jackpot. Good Luck.

RonMar · Nov 10, 2017

Havn稚 ever had a screen problem, but if I do, I will also replace them with an inline can filter.

There are a couple of places you need to let the air escape. One is on top of the fuel filter housing. Loosen the nut there to release air. The next big place is at the top of the injector pump. Standard screw head but it has a ring thru it. With these loosened one at a time(filter first) pump the primer/lift pump till fuel comes out. Once these are purged, then loosen the nuts at the injectors and crank it over till fuel comes out there.

Bob Rooks · Nov 10, 2017

Algelugs, I see that you ignored my post. Ok, no big deal - it's your engine, but you must know that the diesel bugs (dead or alive) are very corrosive and can destroy a fuel injection pump, and injectors.
Yes, the priming pump can be removed from the injection pump body, but that is really unnecessary because the check valves can be removed and inspected without doing it. My experience was that the bugs had corroded and pitted the valve seats so bad that the pump would barely pump fuel. The priming pump can be replaced for around $40 if necessary.

angelugs · Nov 11, 2017

Au contrair Mr. Rooks. Actually I'm in the process of doing pretty much what you suggested but not convinced that's the only problem I have. Just couldn't see why I wasn't getting hardly any fuel spurting out of the primer when I removed the fuel line from the output side and pumped it. So I removed the first fuel line and shot some air through it. No problem there so I turned on the fuel at the petcock and got a trickle smaller than the size of a pencil lead but it was a steady flow. Next I removed the primer to see if it was working properly and it was. Flashing back to all the crud I've found in every filter, I drained the tank and removed the sediment bowl assembly which by the way sucked big time since I couldn't spin it off without first removing the petcock (thank you Mr. Chinese engineer). The entire filtering screen in the tank was rotted away. Now I'm thinking of doing away with the sediment bowl setup and installing an inline filter instead. How much trouble am I going to have removing the fuel tank? Looks like it could test my expletive vocabulary. What makes things worse is my FEL is still on the tractor. FYI, you can purchase stainless steel mesh screen material on ebay in multiple micron ratings.

Bob Rooks · Nov 11, 2017

Ok, thank you for the acknowledgement. Installing an inline primary filter is good but it won't remove water like a sediment bowl will. It appears that you have a real problem with contaminated fuel so it won't hurt to have both. I don't think it's necessary to remove the fuel tank if you can rinse it thoroughly with a garden hose and then apply a heat lamp for drying. If you can get 7µ or 10µ stainless screen that would be great. Make sure it fits with no gaps.
I have personally seen a 4,000 hp EMD diesel engine brought to it's knees because of the bugs, and the ensuing repairs. Here is a good short read on the subject:
Diesel Bug Explained - Bacteria Contamination of Diesel - Freephone

933 939 for more info

angelugs · Nov 30, 2017

Still haven't been able to get my 284 to run. Got a couple more questions. One, if I unscrew the hard supply lines for the injectors at the pump should I be able to see fuel squirting out when I turn the engine over? I drained the fuel tank, dumped a 16 oz. bottle of Power Service tank cleaner in it and let it set over the Thanksgiving holidays. Then I rinsed the tank out with a few gallons of kerosene. I've replaced the sediment bowl assembly with a new one, drained and filled injector pump with fresh oil, checked that the hand primer is getting fuel and pushing it through to the filter then to the input side of the injector pump. Still wasn't seeing any fuel at the injectors so I removed each line and shot air through them. After that I still wasn't seeing fuel so I removed all three lines from the pump and turned over the engine. No fuel coming out of any of the outputs. Second question is, how long do you have to crank (or how many times) to bleed the system?

thepumpguysc · Nov 30, 2017

IF you have fuel UP TO the inj. pump inlet & nothing coming out, the control rack is stuck.
You'll have to dig deeper..
Remove the inspection plate on the side of the pump & unstick the rack.. its supposed to move right & left.. its stuck.