John Deere Yanmar diesel engine just stopped

[Nigelr]

Okay I got the pump off. Tips are

I had to make my own mark on the idler gear because the original was hidden by a bolt head when it was in position.
The next tricky bit was the inlet manifold which needed a 1/4 drive socket with a u/j,
then the gear driven wheel needed a proper hub puller, and
finally I had to cut down a 12mm ring spanner to get clearance for the 3 pump flange bolts.

So I sent it off and the good news is that the pump was the fault, it had a broken driveshaft. The bad news is that it had broken from general disaster in the internals, caused by fuel contamination, and the bill is £1573 with tax!

So this is a cautionary tale for any fellow innocents. The machine gets through a fair bit of diesel so I switched from buying 200-litre drums to using an IBC tank and buying 500l from a tanker which is about half the price. I didn't know about needing a biocide and by the time I realised something was wrong and water was separating out not leaking in, evidently it was a bit late.

Last winter I cleared the mower's fuel system. even vacuuming out the tank, but as Pump Guy said I think, this pump has zero tolerance for water in the fuel and it was too late. Of course it's second-hand and I don't know its history but I assume this was all down to me.

So I hope this helps someone! Thanks again to Spanner, Pump Guy, Egon, Luke and Coyote for your support

 

[Egon]

Nice to see the problem identified.

 

[Spanner]

Oh Deere!
Well, we got about as close as we could get to that diagnosis at Post #44. Gear turning is no guarantee of the pumps internals rotating...

That's a pretty radical end-result Nige and I'm sorry for you to have to suffer such a catastrophic pump failure.

1500 incl. VAT is about 1300 net and their estimate of 800 would have not have allowed for water damage sufficient to destroy the shaft - so your repairer has done you a nice job overall I think. It could have been worse, much worse.

Water: Are you aware of the "Red Ring" in your Water/Fuel Seperator unit assembly? This is the item below the electric pump which has the clear-ish plastic bowl. The red ring inside indicates contaminated fuel when water is present by floating on top of the water. You can drain the water out of the screw-valve at the base of the bowl.
After fuel passes through this Seperator it goes through the fine particulate filter above which is the black screw canister with Japanese character writing on the side.

Checking the 'Red Ring' is a daily task for the Operator along with checking the Oil Level, Coolant etc. prior to starting the engine.

Accordingly (and sorry to say) yes, this is "down" to you - But if you didn't know what/where to look then Murphy's Law enters the equation.

Backlapping: 250 is money you can save yourself as the 3235C has On-Board Backlapping and if you need guidance to carry-out this procedure just ask here after reading the Operators Manual which describes the method.

The essential tool is a 5"-6" paintbrush with an extended handle (2 feet long min.) DO NOT attempt Backlapping with anything shorter.
Backlapping paste is available through your dealer or ask at your local Golf Club Greenkeepers Shed. The R&R brand is available in UK - It's water soluble so it washes off the blades with a hose - and the #80 Grit should suffice for your needs.

Regards,
:wrench:

 

[Nigelr]

Ah I hadn't tuned into the significance of the red ring Spanner, though I have been keeping an eye on the separator bowl. The fuel has been dry all this year so it's a bit disappointing that the pump kept deteriorating, but I suppose there are bound to be a few painful lessons being an amateur using professional kit.

I have been backlapping, thanks. It does generally need quite a lot of maintaining doesn't it? I have to keep focussing on the effect it has on my property, which now has about 3 acres of lawn instead of a field!

Anyway I'm glad that with your help I did this myself, because if I'd called in a dealer and then had the bill I'd have found it hard not to feel I'd been treated like a golf club! But as you say the pump repairers do feel legit.

 

[Nigelr]

So guys, I've got the pump back, the same pump but shiny and looking new. Starting to refit it I've hit an issue straight away I hope you could help me with:

I left the engine as it was before I removed the pump, with the idler and driven gear with the paint marks lined up, and it hasn't been moved since. The pump rotates to one of 3 positions, with a strong spring action, and won't stay in any intermediate position, and at its closest the key is maybe 20 degrees away from lining up with the keyway in the gear.

What to do? Is there a technique?

 

[thepumpguysc]

The pump is SUPPOSED TO be set w/ a dial indicator.. but just rotate the dr. shaft to line up w/ the drive gear & install..
Tighten everything up & start.. You may have to go back & move the drive plate to fine tune the timing to your likeing.. or look on the drive for the old bolt pattern..
BUT>> TIGHTEN EVERYTHING UP.. DO NOT try to adjust like a car distributor.. the pump will lock up/seize..

 

[Nigelr]

rotate the dr. shaft to line up w/ the drive gear & install..

Do you mean rotate the drive shaft of the pump? I can't get it to stay in position.

 

[Spanner]

No Pumpy, Nigels pump had a broken shaft so when he's removed it the ... Hang on, that shouldn't make any difference.

The "3-position spring action" effect is the pump working correctly, since you have a 3-cylinder engine.

I think you're going to have to go through the No.1 piston at Top Dead Centre whole timing exercise thing. Unless...

Are there timing marks stamped on the gears or are the red-paint marks just ones you made upon disassembly? (Sorry, I'm confusing myself at 5am here.)

The FIP gear is bolted to a 'hub' which is keyed to the shaft and secured with a nut.

Did you remove the hub from the FIP for you to say the keyway doesn't line up?

Do you have a mark on both the Idler Gear and the FIP Gear that you are aiming to line-up? ... (I hope so.)

Can you 'count the teeth' needed to turn the engine to co-ordinate the gears correctly? (Does that read ok?)

DON'T actually turn the crankshaft yet - Just think through the issue and we'll work it out. I don't have the installation procedure to post with timing etc. Pumpy might?

Will talk about your Cutting Unit maintenance after engine is running.

 

[Nigelr]

Spanner on the driven gear, that the pump shaft keys into, there's a B stamped and next to it a white paint line. On the idler gear, that it meshes with, there's a white paint mark, and I lined these up together before I took out the pump.

Now I can recover to that position but for now I have turned the crankshaft and consequently both those gears, until the keyway lined up with the pump shaft key. My thinking being that this is the only way it can fit and it's not really different from rotating the shaft of the pump, in that after fitting I could have rotated the crank back to its starting position and with it the pump shaft. I'd be in the same situation as if I'd been able to stop the pump shaft 20 degrees further round.

Then I lined up the two kind of chiselled lines on the flange of the pump body and the 'back' face of the gearcase, as they had been. In my mind it's the same pump.

I am assuming that the pump has been rebuilt with exactly the same timing, the repairers haven't said either way and being the weekend I can't ask.

 

[Spanner]

The pump isn't 'timed' internally per se, other than having a keyway.

After installation it is 'timed' to the crankshaft by use of the adjuster slots on the flange allowing it to rotate some degrees slightly. This is where Pumpy and his Dial Indicator come in.

You can get it very close using the marks left on the flange by the mounting bolts, paint, etc.

If you think you've got it installed correctly, rotate the crankshaft two full turns and the timing marks should all line up again, as they were.