B1550 not starting after replacing cylinder head

jamesrhansen

New member

Equipment
Kubota 1550HST
Jun 11, 2020
28
2
3
PA
I have a B1550 HST that will not start after replacing the cylinder head.

The following have been replaced

New Battery
New cylinder head
new head gasket
new top radiator hoses
new thermostat

Glow plugs ohm out to 1.2 ohms each
Engine turns produces white smoke
Cleaned fuel filter
bled fuel lines starting at the one in the back and moved forward bled until diesel squirted out from top of each fuel line where it connects to throttle body
Tolerances set and checked on each rocker arm top of valve

Tried jump starting using second good working battery + to + - to -

Need some help any ideas or suggestions wold be great. We think it is a compression issue. We try to start for 10 seconds let it cool then try 10-15 seconds let cool.

Doesn't start using ether or by spraying diesel into air intake

Thanks
 

jamesrhansen

New member

Equipment
Kubota 1550HST
Jun 11, 2020
28
2
3
PA
What happened for you to decide to replace the cylinder head?

Dave
There was a minute crack int he old cylinder head and the engine would overheat quickly. We replaced the head gasket before replacing the cylinder head and it still overheated. We removed the old cylinder head and gasket and replace the gasket with a new one and the cylinder head with a new one. The new cylinder head came with new valves installed and new springs caps and collets (collars that hold the valves in place)
 

jamesrhansen

New member

Equipment
Kubota 1550HST
Jun 11, 2020
28
2
3
PA
I will check on the smell if it does smell sweet then should i drain the coolant and engine oil and then replace it ?
The head gasket and head were torqued to the proper ft-lbs I replaced the intake manifold gasket, and exhaust manifold gasket when I replaced the cylinder head.
 

Dave_eng

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M7040, Nuffield 465
Oct 6, 2012
5,128
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Williamstown Ontario Canada
After all you have done, I am inclined to go back to some basics just in case...............

Your tractor provides power to the engine stop solenoid to shut down the engine. No power to solenoid means engine is getting fuel.

A timer applies power for a few seconds to the solenoid when the key is turned to OFF which stops the engine.

Check that there is no power to the solenoid with the key in ON and START.

You measured the glow plug resistance. Have you verified that the glow plugs are being powered both in a pre heat position and also the START key switch position.

Stay away from Quick Start.

A compression check would be in order after the above checks.

If easier, as a first step, bring a cylinder to a position where both valves are closed and put compressed air into the cylinder to see if there is obvious leakage.

Dave
 

Pau7220

Well-known member

Equipment
L3650 GST, Landpride TL250 FEL w/ Piranha, 6' King Kutter, GM1084R Finish
Aug 1, 2017
785
276
63
Scranton, PA
fuel line where it connects to throttle body
Diesels don't have a throttle body.... they must be bled at the injector with the throttle wide open

Doesn't start using ether or by spraying diesel into air intake
Don't spray anything into a Kubota.... it can cause SEVERE damage to pistons or rods

We think it is a compression issue.
You may be barking up the right tree. If the injectors are bled properly a compression test is in order. How long was it sitting open or with coolant in the cylinders? Rings may be stuck. Please say you didn't use a whizzer / Roloc disc to clean the block.... many engines have been destroyed with these. The abrasives cause vertical scratches on the rings and cylinders resulting in compression loss. Rust on the cylinder walls from sitting open will do the same thing.
 
Last edited:

jamesrhansen

New member

Equipment
Kubota 1550HST
Jun 11, 2020
28
2
3
PA
Diesels don't have a throttle body.... they must be bled at the injector with the throttle wide open


Don't spray anything into a Kubota.... it can cause SEVERE damage to pistons or rods


You may be barking up the right tree. If the injectors are bled properly a compression test is in order. How long was it sitting open or with coolant in the cylinders? Rings may be stuck. Please say you didn't use a whizzer / Roloc disc to clean the block.... many engines have been destroyed with these. The abrasives cause vertical scratches on the rings and cylinders resulting in compression loss. Rust on the cylinder walls from sitting open will do the same thing.
I did not use any abrasives on the top of the block. I sprayed grease cleaner on a microfiber rag and wiped it off it really wasn't dirty at all.

When I took the head off I cleaned out the coolant with shop towels to get it out of the cylinders.

I bled the fuel lines at the top of the block starting at the one furthest from the from of the tractor and bled it by trying to start it until diesel was shooting out then did the other two fuel lines the same way. I also removed the rubber return hose from the last fuel line that goes back to the tank and tested by trying to start and diesel was squirting from it.

Thanks
 

jamesrhansen

New member

Equipment
Kubota 1550HST
Jun 11, 2020
28
2
3
PA
Diesels don't have a throttle body.... they must be bled at the injector with the throttle wide open


Don't spray anything into a Kubota.... it can cause SEVERE damage to pistons or rods


You may be barking up the right tree. If the injectors are bled properly a compression test is in order. How long was it sitting open or with coolant in the cylinders? Rings may be stuck. Please say you didn't use a whizzer / Roloc disc to clean the block.... many engines have been destroyed with these. The abrasives cause vertical scratches on the rings and cylinders resulting in compression loss. Rust on the cylinder walls from sitting open will do the same thing.
I did not use any abrasives on the top of the block it was rather clean.
When I took the cylinder head off i used shop towels to absorbs any coolant and oil off top of the block.

should i remove the cylinder head lubricate the pistons with some fresh motor oil reinstall the cylinder head and torque bolts and try again.

I will have to buy a compression test tool unless you can rent them at Auto Zone or advance auto
 

Pau7220

Well-known member

Equipment
L3650 GST, Landpride TL250 FEL w/ Piranha, 6' King Kutter, GM1084R Finish
Aug 1, 2017
785
276
63
Scranton, PA
I did not use any abrasives on the top of the block
Good (y)

Next step is the compression test. You need a diesel tester. Available from harbor freight at a reasonable cost. Some use injector ports, some use glow plug depending on adapters in your kit. Do a dry, then a wet test with a small amount of oil squirted in the cylinders. If there is no change the new valves may be leaking. If it's an aftermarket head could be they weren't lapped properly. After that charge the cylinders with air and listen for air leaking at the intake and exhaust.... also at the crankcase vent.
If there's a big change between dry and wet, it's a bottom end issue.
If you pull the head you'll need a new gasket.
 
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Jim L.

Active member
Jun 18, 2014
815
88
28
Texas
should i remove the cylinder head lubricate the pistons with some fresh motor oil reinstall the cylinder head and torque bolts and try again.

Should do diagnostics. Fuel: solenoid check as already suggested. Compression: fuel ignites on heat of compression. Good suggestions already made to check valve seal and general compression.

Compression test kits available for loan or rental at chain stores such as Auto Zone, Advance Auto, and others.
 

jamesrhansen

New member

Equipment
Kubota 1550HST
Jun 11, 2020
28
2
3
PA
Good (y)

Next step is the compression test. You need a diesel tester. Available from harbor freight at a reasonable cost. Some use injector ports, some use glow plug depending on adapters in your kit. Do a dry, then a wet test with a small amount of oil squirted in the cylinders. If there is no change the new valves may be leaking. If it's an aftermarket head could be they weren't lapped properly. After that charge the cylinders with air and listen for air leaking at the intake and exhaust.... also at the crankcase vent.
If there's a big change between dry and wet, it's a bottom end issue.
If you pull the head you'll need a new gasket.
I will go to harbor freight on Tuesday and see if they have one at the store by my house.
I wont be able to test until Thursday or Friday so I will have to pause this conversation until then. Thanks for your help so far. !!
 

Pau7220

Well-known member

Equipment
L3650 GST, Landpride TL250 FEL w/ Piranha, 6' King Kutter, GM1084R Finish
Aug 1, 2017
785
276
63
Scranton, PA

CapnDean

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L6060,ZD1211
Feb 22, 2018
184
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18
Gulfport, MS USA
Holy mackerel! There may actually be a problem that does not fit what I have learned from years of diesel engines in boats. An very old Boat Captain once said to me: "If your diesel engine won't run, you have a fuel problem". Now aside from the occasional 'rod sticking out of the block' or 'seized due to oil starvation' his advice has always rung true. From the description of this problem (Fuel at injectors, white smoke from exhaust) I am going to say that it is a compression issue. Check Valves!
 
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NHSleddog

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B2650
Dec 19, 2019
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Southern, NH
Most of you know this but many people don't.

Diesel does not "ignite" like gas does with a spark plug, Diesel ignites under pressure, so the valves are very critical to ensure a high enough compression to work.
 

jamesrhansen

New member

Equipment
Kubota 1550HST
Jun 11, 2020
28
2
3
PA
I didn't see if anyone asked or answered, but did you set the valve clearances?
Holy mackerel! There may actually be a problem that does not fit what I have learned from years of diesel engines in boats. An very old Boat Captain once said to me: "If your diesel engine won't run, you have a fuel problem". Now aside from the occasional 'rod sticking out of the block' or 'seized due to oil starvation' his advice has always rung true. From the description of this problem (Fuel at injectors, white smoke from exhaust) I am going to say that it is a compression issue. Check Valves!
I went to Harbor freight last night to purchase the diesel compression tester and they were sold out. I will have to order online and get it delivered as soon as it comes in I will check compression and let everyone know

Thanks
 

Roadworthy

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L2501 HST
Aug 17, 2019
1,649
525
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Benton City, WA
Okay, I got that the valves were set. At the risk of offending though, did you rotate the engine so the valves were completely closed when you set the clearance? I know it's a stupid question for someone who knows what he's doing but I've had to stop myself from time to time and go back and do it right.
 
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