Injector pump leaking diesel into the pumps oil tank

[Bob Rooks]

Follow up. Electric pump still works great. but I see I still have diesel diluting the injector pump oil. Tractor runs great

I have only used the tractor for 10 hours in the last year or 2. Yesterday, I pull the dipstick on the injector pump and fuel gushed out.

I assume this confirms the clearance of the pump plungers is just too sloppy.

Questions;

I assume if I drain the fuel out of the oil sump and replace with 30 W, diesel will flush it out quickly. How long will an injector pump last with diesel fuel as the lube??

Would using a gear oil last longer?

When an injector pump fails, will it damage anything else? Run it until it dies?

I still see my injector on Aliexpress, $183 plus $135 shipping.
Anyone buy parts from AliExpress?
How difficult is it to replace an injector?

https://www.aliexpress.us/item/2255800463164515.html?spm=a2g0o.productlist.main.1.42bab6e0QcqDlp&algo_pvid=fc8e1ba9-154e-4783-9fc6-afa1f33fe9ba&algo_exp_id=fc8e1ba9-154e-4783-9fc6-afa1f33fe9ba-0&pdp_npi=3%40dis%21USD%21198.00%21174.24%21%21%21198.00%21%21%4021021d8f16902145603875859d075e%2112000029569401447%21sea%21US%210&curPageLogUid=MPaT0BMSxkKZ

Your fuel contamination is likely coming from the lift pump you still have installed. You need to take it out of the equation since you have an electric pump now. Shut off the fuel every time you're finished with the tractor, this will help a little.

So, if your trash your injection pump/governor assembly what could go wrong? Worst case scenario would be the rack stuck in WOT and the governor failed (seized) from improper lubrication = runaway engine that may come from together.
Replacing an injection pump isn't difficult, it's timing it that's kinda technical, and throws off the novices every time.

 

[Paddy]

Bob,

when I installed the new ele pump, I did take off the mechanical lift pump and replaced it with a plate a gasket as directed above. I do have compression release and assume this would shut off the run away engine.

Though I'm a mechanical engineer, I would likely fall into the novice category.

 

[Bob Rooks]

Good to know, glad you have it blanked off. I'm a chief engineer myself and have a strong background in earthmoving equipment, and diesel engines in particular, and licensed for medium voltage.
Yes, a compression release would likely stop a runaway, but I wouldn't guarantee the valve train would survive unscathed. Preferred method is to stop the intake air supply. Detroit Diesel has an air dam fitted to all of their two stroke engines
I am a novice at many things.....

 

[Paddy]

Bob,

Have you ever bought parts from AliExpress?

Though I'm an ME, I have worked my entire career in high voltage substation porcelain insulators.

 

[Bob Rooks]

Bob,

Have you ever bought parts from AliExpress?

Though I'm an ME, I have worked my entire career in high voltage substation porcelain insulators.

I haven't personally, but I understand it's the Chinese version of Amazon. They have warehouses in the US, but some of their shipping rates are high.

 

[254OZ]

I have been following this thread with interest as I also have a Chinese tractor that leaks diesel in to the Injector pump oil reservoir.
My tractor is a Jinma 254 with a Laidong KM385BT engine. I bought it new in 2014 and it now has 465 hours on it without any major problems. I have meticulously maintained it and became aware early on (at about 100 hours) that the IP oil was slowly getting diluted with diesel although it didn't seem to cause any problem. I thought it was probably due to the fairly simple design and questionable Chinese manufacturing tolerances and hoped that changing the IP oil at 100 hour intervals and keeping an eye on it would be OK. It hasn't seemed to get much worse over the time since then although I decided at 300 hours to start changing the IP oil at 50 hour intervals to be on the safe(r) side.
At the 400 hour service (about 18 months ago) I decided to fit an electric lift pump and a blanking plate as suggested earlier in this thread. I used a cheap Ebay pump (type HEP-02A) and it has worked without problems since. Some diesel still leaks in to the IP pump oil but the rate of dilution seems to be less than before to the point that I am returning to my previous 100 hour IP oil change.
My KM385BT engine has no compression release and no glow plugs but always starts extremely well. It does have a device on the inlet manifold I have heard referred to as a flame thrower. I have no information on it but I believe it aids starting. I am in Western Australia so it doesn't ever get very cold here so that might be something to do with the starting too.
So, was it worth fitting the electric pump?. Yes, I think it probably was, even if it wasn't the complete fix I was hoping for. Also, it makes bleeding the fuel dead easy compared to the mechanical pump.

 

[Bob Rooks]

The barrel and plunger assemblies in the fuel injection pump are a lapped fit and have no seals, so you can always expect trace amounts of leakage. Also, the barrel and plungers are lubricated only by fuel so it is in the owner's best interests to keep the fuel as clean and dry as possible. Some injection pumps are lubricated by the engine's pressure system, but then you have to be more watchful of the engine oil.

 

[Paddy]

Follow up. I was able to order the injector pump. It took a lot of back and forth. The pump was about $100 and UPS shipping $80.

I understand installing one of these is not real simple so I'll plan the time slot carefully.