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Wayne
Wayne, Journeyman
Category: Construction and Road Equipment
Satisfied Customers: 8431
Experience:  worked on many road graders, Bull dozers , skid steers, Rollers
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I have a kubota mini ex. Looks like a 17 or 18 hp 3 cyl

Customer Question

I have a kubota mini ex. Looks like a 17 or 18 hp 3 cyl diesel.
It is really hard to start when cold. Impossible to start when hot.
Checked glow plugs, replaced one bad one. Changed fuel. Fuel flows well.
Notice a lot of air in return line off injectors when running. Haven't seen that before on other diesels I had.
Put in new battery turns over quickly.
Not much smoke though and when won't start no smoke at all.
If you hit it with ether when cold it will kick back and then run with starter for a while then start.
But if hot no amount of ether helps.
Submitted: 1 year ago.
Category: Construction and Road Equipment
Expert:  Wayne replied 1 year ago.

Hi I'm Wayne

I will help you with this

That sounds like a valve/compression issue

have you adjusted the valves,

it is critical on them engines

intake and Ex both .006-.007

Hi, If this helped you

Please rate my answer 3 or more stars

Do not use the Poor/Bad rating,

Click on the more info request

Thank You

Wayne

Customer: replied 1 year ago.
I will have a look. But why no smoke ?
Typically no.smoke is a fuel problem and compression wont affect that . Right?
Expert:  Wayne replied 1 year ago.

Hi

I believe you have 2 issues here

let's work on the compression 1st , then we will move to the fuel issue

also when was last time fuel filter changed

drop it to see if it is low on fuel or spilling over

Hi, If this helped you

Please rate my answer 3 or more stars

Do not use the Poor/Bad rating,

Click on the more info request

Thank You

Wayne

Customer: replied 1 year ago.
Adjusted valves. Don't thiink they were too bad. No difference on start.
Fuel filter is fine. Fuel flow is full bore when line removed in front of pickup pump.
Fuel is present at injector pump.
Expert:  Wayne replied 1 year ago.

OK

Thank you for that , now loosen the lines at the injector

crank over and see if you are getting a good quantity of fuel

if not then check the fuel shut off solenoid , make sure that is working

Customer: replied 1 year ago.
Ok. So i had it running. At near full throttle for about 10 minutes. Then it started to falter and slow down.
Bringing it down to an idle it was running rough then stalled.
Obviously a fuel problem.
The pick up pump is new.
The guy before me changed it.
I had an oil leak because he did not remove anpf old gasket so i removed cleaned and put back on.
While I had it off I checked that it was working by loosening inlet to injector and depressing plunger that would normally be actuated by cam shaft.
I then checked if have fuel at injectors as you suggested and i do.
But not at first. Had to turn it over several times to get it.
Customer: replied 1 year ago.
I doubt fuel shutoff solonoid is issue as I have had it runnimg. Butas a matter of interest what would it look like ?
Customer: replied 1 year ago.
Btw. The fliter is just a little in line unit. Clear plastic you can see its full.
Plus i took the line off in front of and watched it and after it and watched it flow. There is no appreciable difference in volume. There alpewra to be a in lune one way valve between the filter and the pick up pump. It is orianted correctly and once again no appreciable reduction in flow after the valve.
Are there any filters or screens inside the injector pump that can be ome clogged and can be removed or cleaned ?
Expert:  Wayne replied 1 year ago.

Hi

OK, this is interesting,

I suggest you install a 1 way check valve at the

fuel pump, so it can not leak down or back

see how that works

Wayne

Expert:  Wayne replied 1 year ago.

Hi

OK, this is interesting,

I suggest you install a 1 way check valve at the

fuel pump, so it can not leak down or back

see how that works

Wayne

Customer: replied 1 year ago.
Like I say it has one.
However i havnt checked that it works.
I will look at that tomorrow.
Still i dont think that would cause it to stutter and stall after 10 mins operation.
Expert:  Wayne replied 1 year ago.

Morning

It would cause that being that it running out of fuel

yes check the check valve

Customer: replied 1 year ago.
the check valve is fine.
Expert:  Wayne replied 1 year ago.

Morning

Well it is a fuel issue no doubt

I would say the only thing left is fuel pump, or injection pump

I would suggest the fuel pump

Wayne

Customer: replied 1 year ago.
Fuel pump is new.
And working.
Expert:  Wayne replied 1 year ago.

Hi Thank you for that

I was reading back in your posts,

very hard to start when it is hot,

did you do a compression test

Customer: replied 1 year ago.
No. I assume the compreson test would have to be done at the glow plug port or injector port?
I only have a set for a gas engine so the fittings are all for standard spark plug threads.
Expert:  Wayne replied 1 year ago.

Hi

You can use one of them with the rubber tip

and hold it in with 2 hands and have someone crank it

Expert:  Wayne replied 1 year ago.

Hi

You can use one of them with the rubber tip

and hold it in with 2 hands and have someone crank it

Customer: replied 1 year ago.
Injector or plow plug port
Expert:  Wayne replied 1 year ago.

Hi Sorry for delay

We have company from out of town, Colorado

glow Plug port , looking for 325 to 450 LBS

Expert:  Wayne replied 1 year ago.

Hi

I'm Just following up with you

did my answer help you ,

let me know Please

Customer: replied 1 year ago.
Havnt been able to get back to it. Will have to wait till saturday.
Expert:  Wayne replied 1 year ago.

OK, Thank you

Expert:  Wayne replied 1 year ago.

Hi just following up with you

did my answer help you

Let me know Please

Wayne

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