Gray smoke and strong smell

Mx5000

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Equipment
Kubota mx5000
Jun 25, 2018
11
0
0
Ohatchee, Alabama, USA
So I have recently replaced the head on a MX5000(4wd) (V2403). The previous head had a crack between oil port and water jacket. After replacing parts and starting I am getting a lot of gray smoke that seems like unburnt fuel. Could I have messed up an injector while swapping them to the new head? What is the troubleshooting procedure for this? The tractor seems to run ok. Do I crank up and start breaking lines at the injector and see if the engine sputters? How do I do this with out getting sprayed? Could this be something else?


On a side note; I replaced a broken tach cable and when I cranked engine the tach needle spun 360 degrees and broke needle and just kept on spinning. Any ideas as to what could cause this?
 
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D2Cat

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L305DT, B7100HST, TG1860, TG1860D, L4240
Mar 27, 2014
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40 miles south of Kansas City
If you're wanting to check the injectors to isolate which one it might be, you can start the engine and when it is running loosen the nut on the line at the top of the injector a couple(2) of turns. If nothing changes in the way the engine runs that injector is doing nothing.

Tighten it back up and go to the next if it stumbles. That injector is working.


A couple of turns will only let fuel dribble right there at the nut.
 

MilkyWay

Member
Dec 5, 2010
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Dahlonega, GA
....On a side note; I replaced a broken tach cable and when I cranked engine the tach needle spun 360 degrees and broke needle and just kept on spinning. Any ideas as to what could cause this?
I'm glad this happened to you!! No,, wait, that didn't come out right.
What I mean to say is that the first and only time my tach spun 180° in the-blink-of-an-I, and broke the needle off near the base, is when I had the instrument panel off for the 1st time then re-assembled it. I very innocently reconnected the cable and the electrical plugs, fired it up and closely watched the needle peg against the clock-wise stop and break off, with low start-up/idle rpm. It, the tach immediately settled down to normal rpm indications. I don't see how the electrics could have anything to do with a cable driven tach, but to this day I think there must be a "reset" of some kind on the instrument panel assembly to assure this does not occur. You are the only other person to mention a similar situation, not that I feel any better about my experience as you ended up with a damaged needle as well as I. I don't know if the needle can be accessed for replacement or not, and I guarantee no one sells a replacement needle. My tach still works by the way, as nothing like that has ever happened before or since. The needle broke off 1/4" from the "base" such that I can claim that it still works and reads correctly. I even mentioned this in my old post concerning a BAD hydro leak on my L5450. It had been a while since the panel R&R and I forgot that the tach was cable driven and therefore blamed the broken needle on a failure on my part to know about said "electrical panel reset" procedure.
 
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thepumpguysc

Member
Aug 8, 2018
267
1
16
Sunny South Carolina
When u swapped the inj. from 1 head to the other..
did you use new washers? did you use new pre-cups? did u TORQUE the injectors in the head? or just "crank'm on down"??
How about the valves?? are u experienced in "setting/adjusting" valves? do u know what the lash is?
You can break the line free AT the injector & BEFORE loosening it, draped a shop rag around the line to keep from getting sprayed..
Its NOT fool-proof> but it helps..
Depending on WHEN you get the smoke, is how you should test it..
IF the smoke is at idle, break the lines loose at idle..
IF the smoke is at part or full rpm.. well, u know the rest..
The injectors have a small needle{pintle} that stick out of the end of the nozzle..
IF you damaged THAT, the spray pattern will be greatly affected.. causing an incomplete fuel burn in the cylinder & depending on how bad it is.. wash-down a cylinder.. {flood w/ fuel}
Breaking the inj. loose 1 @ a time "should" show if that's happening.. Just watch the smoke.. Good luck & heres hoping for the best..