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Tomotomo



Member Since: 13 Feb 2018
Location: Bucks
Posts: 71

United Kingdom 
2 cylinder diesel engine advice
Maybe could tell me the likely cause of my kubota z482 dumper engine refusing to start even with easy start.... I have had whole fuel system apart injectors are firing. So that leaves air and compression. As there is plenty of air its something compression based.
It could be loosing compression through push rods I can see vapour puffing up when I crank.?! Valves all seem to open and close ok. Would a piston ring failing cause this? Any advice greatly appreciated Bow down
Post #894585 28th Mar 2021 9:21pm
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#1784



Member Since: 11 Nov 2020
Location: Almunge
Posts: 40

Sweden 
Do you get smoke out of the exhaust?
Assuming this is a hydraulic machine, there is one more possibility, that the hydraulic system is loaded preventing the engine to start. Make "really" sure all controls and levers are in "neutral" position"
Post #894588 28th Mar 2021 9:31pm
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Tomotomo



Member Since: 13 Feb 2018
Location: Bucks
Posts: 71

United Kingdom 
Yes machine is hydraulic. All controls in neutral. It wont turn over with any levers engaged. Yes it smokes from exhaust when you crank. A thick grey smoke. Occasionally one cylinder catches but never amounts to anything.
Anybody know if its possible for injection timing to go out.? I think its cam driven so I had ruled that out, but I am at a bit of a loss now. Thanks for your help
Post #894592 28th Mar 2021 9:36pm
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Bluest



Member Since: 23 Apr 2016
Location: Lancashire
Posts: 3993

United Kingdom 2007 Defender 110 Puma 2.4 XS CSW Java Black
Does it have a decompression lever/mechanism? My little Yanmar diesel does. If so, maybe it’s partially or fully engaged? 2007 110 TDCi Station Wagon XS
Post #894598 28th Mar 2021 11:03pm
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#1784



Member Since: 11 Nov 2020
Location: Almunge
Posts: 40

Sweden 
How did the problem start? "Out of the blue" one day or has there been increasing starting issues over time?

I still think your symptoms are matching that it's trying to start but is held back by hydraulics. Before tearing the engine apart, is there any way of ensuring there is no load on the engine at startup, either remove the pump(s) or by putting pressure line(s) directly to tank?
Post #894609 29th Mar 2021 6:50am
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Notyalc



Member Since: 27 Jul 2018
Location: Northumberland
Posts: 139

United Kingdom 2003 Defender 90 Td5 HT Epsom Green
Re: 2 cylinder diesel engine advice
Tomotomo wrote:
Maybe could tell me the likely cause of my kubota z482 dumper engine refusing to start even with easy start.... I have had whole fuel system apart injectors are firing. So that leaves air and compression. As there is plenty of air its something compression based.
It could be loosing compression through push rods I can see vapour puffing up when I crank.?! Valves all seem to open and close ok. Would a piston ring failing cause this? Any advice greatly appreciated Bow down


Does it have glow plugs?

If they aren’t working it will not want to start. Smoke suggests you are getting fuel, but without heat it won’t want to fire very easily.

Also needs to be spinning fast, so good battery needed.
Post #894625 29th Mar 2021 8:21am
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blackwolf



Member Since: 03 Nov 2009
Location: South West England
Posts: 16808

United Kingdom 2007 Defender 110 Puma 2.4 DCPU Stornoway Grey
My suspicion would be a lack of compression, especially if easy start has been used regularly.
Post #894627 29th Mar 2021 8:34am
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Tomotomo



Member Since: 13 Feb 2018
Location: Bucks
Posts: 71

United Kingdom 
Thanks for all the advice.
I have just replaced glowplugs with brand new set.
I never use easy start. It was an act if desperation to see if it would do anything.
Recent history up to this point. Used machine a week ago noticed it sometimes cut out at idle. Checked fuel filter and was slightly deformed. So parked machine up in shed.
Following weekend fitted new fuel filter and an additional pre filter and new glowplugs.
Bled fuel system. And a Shocked load of cranking later nothing!
Left it until following weekend. Entire injection side apart lines blown through and injectors tested on pump. Bled a load of cranking and nothing... tried spraying easy start tiny kick but nothing really. Tried again this weekend even heated up head with hot air gun... absolutely zip.
Post #894710 29th Mar 2021 4:03pm
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Dinnu



Member Since: 24 Dec 2019
Location: Lija
Posts: 3140

Malta 2012 Defender 90 Puma 2.2 CSW Santorini Black
Maybe try to squirt some engine oil down the heater plug holes, that can help seal the rings if it is a compression loss from the rings. 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black
Post #894754 29th Mar 2021 6:42pm
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Tomotomo



Member Since: 13 Feb 2018
Location: Bucks
Posts: 71

United Kingdom 
Ok thanks, I will try the engine oil down the cylinders. How much shall I put in, 100mm in each ? Do I leave It to soak for 24hrs or do I try cranking straight away?
With regards the hydraulics being engaged I am pretty sure they arent as all levers and linkages are in neutral positions.
I have even tried removing alternator to reduce drag on engine but made no difference.
There is no decompression lever on these engines.
I suppose it always took a few spins to fire up but always did. It also has loads of power over entire rev range so never really considered it reaching the end of its life...thanks for all the tips Thumbs Up
Post #894766 29th Mar 2021 7:10pm
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htb2



Member Since: 02 Nov 2018
Location: aberdeenshire
Posts: 507

Scotland 
Would not put as much oil as that down bores as could hydraulic it
Post #894772 29th Mar 2021 7:24pm
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Dinnu



Member Since: 24 Dec 2019
Location: Lija
Posts: 3140

Malta 2012 Defender 90 Puma 2.2 CSW Santorini Black
100ml is a bit too much. Engine capacity is about 500cc, so probably combustion chamber is not much larger than perhaps 25cc.
But what you can do is after injecting the oil, turn it over a couple of times with the heater plugs still out so any excess oil is ejected from the heater plug holes during compression. You will also wet the valves to make for a better seal as well.

Then try to start it up right away.

Edit. 25cc combined combustion chamber volumes assuming CR of 20. So each cylinder will be somewhere around the 12 or 13cc. 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing
2012 90 CSW, 2.2TDCI, Santorini Black
Post #894780 29th Mar 2021 8:11pm
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Tomotomo



Member Since: 13 Feb 2018
Location: Bucks
Posts: 71

United Kingdom 
ok thanks. I will try adding the oil to the cylinders tomorrow.
Post #894796 29th Mar 2021 9:07pm
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#1784



Member Since: 11 Nov 2020
Location: Almunge
Posts: 40

Sweden 
Hot air gun down intake during starting can aid as well, but sounds like there is something else going on, as mentioned perhaps lost compression for some reason.
One last try on the hydraulics, please try to hold one of the hydraulic levers to activated position when trying to start, preferably one that is directly activated (not pilot controlled) and for a "light load" function
Post #894802 29th Mar 2021 9:32pm
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Tomotomo



Member Since: 13 Feb 2018
Location: Bucks
Posts: 71

United Kingdom 
Update
Big thanks to Dinnu for the engine oil down the cylinder tip.
Did that and it fired up straight away! So this suggests it was/is iffy compression.
So at least the mystery is solved.
I have a compression test kit arriving tomor so will see what's going on..
Do we think that all my cranking and subsequently all that diesel spraying into cylinders could have washed the residual oil away on the bores causing the piston rings to loose their sealing abilities?
I'm not denying the engine might be worn but could this series of events highlighted it? Or is that all wishful thinking and I should be looking to get a replacement engine Big Cry Anymadsivev
Post #894993 30th Mar 2021 7:21pm
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