JD 850 Yanmar Injector Pump instructions needed

[Summercloud]

I'm working on a 1986 John Deere 850 tractor with a 3 cylinder Yanmar engine.
The owners said it wouldn't start after not running it for a number years.

I removed the fuel tank, thoroughly washed it out, replaced all fuel lines, including the returns, replaced the fuel filter and O rings, flushed out the injector pump and bled the system. After a good charge, it fired up. Ran fairly even, but the acceleration and idle were erratic.

I noticed the throttle lever had been damaged and modified (cowboy tractor). So I removed the Governor inspection plate, Injector Pump and side plate. The Pump was a bit gummed up, the governor spring was chewed up from the cam gear and the governor link and lever adjustment were swinging in the wind.

Prior to reading that this pump has the makings of a Swiss watch, I disassembled it, washed it and reassembled it (using my best judgement and the increments and markings on the different parts). Bought a new spring and set up the governor as per some instructions I found posted here on TractorByNet (thanks).

It seems to run a bit better, but not as smooth idling as I would think, and it feels like it's pulling too hard under load. I suspect the adjustments of the Injector Pump is still off some what. I've searched for just some tech information, but it's like finding the Holy Grail.

Does anyone know where I can find some information on the Injector Pump rebuild settings? I could just keep pulling it and resetting and maybe get it right, but I'm afraid I going to wear out the nuts and bolts after too many tries.

 

[beenthere]

:welcome: to TBN

Might that info be found in the service tech. manual that covers the JD 850?

 

[Summercloud]

Thank You, 'beenthere'!

Perhaps... but I'm not sure. And, neither I nor the owner want to spent $300 for the tech. manual just to view one page, one time, that might not even contain the calibration specs we're looking for.

I was just hoping some experienced soul out there might have been there-done that, and could point to a downlaodable .pdf of just the settings. I did see a post where someone did just that for other tech. info. But that was among the dozens I have viewed... still looking.

This Injector Pump is a fairly simple minded mechanism, most Wrenchers can disassemble and reassemble it. Yet, like the complexity of a clock, if the time is not accurately set, it's function is deemed worthless.

The unit I'm working on was just gummed up with stagnate fuel. The internal machine surfaces are immaculate. I cannot see scrapping it as a core for a questionable rebuilt unit of even a new replacement. It sorta defeats the purpose of rebuilding this old tractor and just purchasing a New one.

 

[beenthere]

$300 ??

That is a bit on the high side.
Per a previous post on here... $45
http://www.tractorbynet.com/forums/private-party-ads-archive/173548-jd-850-1050-factory-service.html

Google jd 850 service manual and look at the various hits. Can also order from Deere.

Likely you could talk to a Deere service dept and get get the schematic printed from a service book there. I'd be surprised (although it is CA) that they wouldn't help you out. They may look at you as potential good customer, if they are on their toes.

 

[zzvyb6]

Pistons and injection pumps are numberd 1, 2, 3 counted from the flywheel end of the engine.

Engine flywheel has 3 sets of timing marks. The sets are numbered to match the piston numbers.

Turn flywheel until the number 3 piston TDC mark aligns with timing index mark on starter housing. (Number 3 is the reference because 1 and 3 are hidden by the frame, etc.

Attach tool JDF-14 or an old cutoff piece of fuel injection line onto fuel injection line #1 with a drop catch can at the end.

Turn key switch on. Do NOT start engine. Push fuel shutoff solenoid plunger in.

Turn flywheel clockwise (viewed from flywheel end) until fuel flow stops.

Keep turning flywheel clockwise slowly until fuel flows again in a stream.

If fuel flow does not stop, you are on the exhaust stroke instead of the compression stroke.

Slowly turn flywheel counter clockwise until fuel flow changes from a stream to drops then stops.

turn key off. Flywheel is now at the point of beginning of fuel injection.

Check position of timing mark on flywheel. Timing mark on flywheel must be aligned with timing index on starter plate.

If marks are not aligned, for every 2.2 mm that the marks are misaligned, the injection timing is off 1.0 degree.

If timing is less that 1 degree off, no adjustment is necessary.

If more than 1 degree, adjust injection pump timing.

Keep in mind the flywheel turns counter clockwise.

If timing mark on flywheel has not reached timing index, ****** injection timing by increasing total shim thickness under injection pump.

If timing mark has passed timing index mark, ADVANCE timing by decreasing total shim thickness.

Do NOT use old shims. Injection pump timing is affected by using old shims. Measure old shims to determine total thickness.

For every 0.1 mm of shim thickness there is approximately a 1 degree change in position of flywheel.

Shim sizes are 0.2 mm (.008") prodeces 2 deg (4.5 mm) on flywheel.

0.3 mm = 3 deg =6.5 mm.

0.5 mm = 5 deg or 11 mm.

Apparently there can be quite a bit of wear on these shims. They show a typical 2 mm shim that is now 1.1 mm.

Let us know if this adjustment id easy and how much improvement the motor gets ! Good luck.

 

[Summercloud]

$310.95 plus tax.
The Parts Guy at our local John Deere dealer said he would be more than happy to order it, if paid in advance. He said it is the same Tech Manual they use in their shop (1800 pages). And, it MAY have something in there about the Injector Pump rebuild settings and placement of the internal parts? (it does cover every implement the tractor can push or pull)
He could also sell me the 'necessary' special tools for assembling and calibrating it.

When asked if I could just have (or purchase) a printed schematic of just the Injector Pump rebuild, he said it's like the difference in a new Injector Pump and having mine rebuilt ....... about the same price. I didn't bother taking off my boot to figure that one out.

You're right about the 'potential good customer' approach. I went in with a neighbor cattle rancher, he was checking out a little JD110 backhoe. Said he wanted to get it after we got this 850 running. Well, the salesman lit up like Christmas morning. Said they would come out and pick up the 850 and 'get it done right' as soon as we started the paper work on the JD110.
He did give us a couple JD caps as we were leaving.

'I'd be surprised (although it is CA) that they wouldn't help you out.' Yep, we got some of the most helpful service people out here in CA...... that money can buy.

I have a NI-ASE General certification, was #12 in Ca getting my Smog/Light/Brake certificate, I've worked on everything from motorcycles to UH-1s. Have a couple roll-aways of just 'special' tools and a small CAM programed CNC shop. I just enjoy working on my own stuff.
Maybe I'm just too old and stubborn to bend over.... and back up to a service desk.

 

[Summercloud]

Thanks for such a comprehensive and detailed timing instruction, ZZVYB6!

I did get a hand full of New shims and cleaned the block off real good.

After reading your timing change for each increment of shim thickness, I was able to get the timing within 0.5 degree.

The engine does settle down a bit smother, and acceleration is more responsive. However, under load it still acts like it's starving for fuel.
I still suspect my set up on the Injector Pump rebuild is a bit off. So, I'll keep looking for some sort of instructions to get it Exact.... or just keep fiddling until I get lucky?

a broken clock is correct at least two times a day

 

[zzvyb6]

How is your supply fuel pressure? If this has an electric fuel pump booster, see if its going on vacation.

 

[Summercloud]

The fuel supply from the tank to the Injector Pump is gravity fed, there is no electric fuel pump booster.
(the image is of the Injector Pump on the JD850)

 

[Summercloud]

Today I found it is possible to successfully rebuild this Injection Pump, even without the highly guarded instructions and specifications.
With close inspection of each part considered and the purpose of its function in relation to related parts, I was able to set it up as it was originally designed.

Along with properly setting the timing, adjusting the linkage with the governor, the results were a smooth idle, responsive acceleration and maximum output under load. For a 30 year old tractor, its performance is amazing.

We are now pressure washing it, lubing everything and taking it up to Reno, NV this week to trade in on that JD110 the owner wanted.

So, if you are considering rebuilding your own Injector Pump and you have a little time on your hands and don't care to pay the $2K the dealer requires, it can be done. Take note of all settings, take pictures of original. Lay everything out and keep it clean.

And if you're real lucky you might know someone that might share some knowledge or instruction data without feeling you are jeopardizing their job or degrading the Yanmar Tractor Industry.

I remember when the first Japan vehicles came over. It was a number of years before they would allow publications of repairs to Chilton, Haynes and others repair manuals, in an effort to protect industry integrity. It did help strengthen dealerships with the exclusive dealership only repairs and service until they became established and could allow the standard consumer to choose their own repairs.

Being a mechanic and building contractor by trade, I sympathize with the needs of a specialized tradesman. But there are still folks out their that put their own food on the the table and need to twist their own wrenches.