12 volts between the positive terminal of battery and glow plugs at all times, bad?

[Willl]

Those readings are exactly what I would expect you would get.

Any 'smoke' from the exhaust while trying to start ?

Edit; Brian beat me.

 

[SilverLakeFab]

The engine doesn't "free wheel" or anything like that, but it turns over quick enough that it would typically start (or did last fall). I've jump started it with my truck a couple times before when I left the key on accidentally, and it turned over a good bit faster, but that was with a running vehicle.

I do get "smoke" (atomized fuel and air mixture) that comes out the exhaust when it's cranking over. It's the same typical amount that I was getting when the machine ran last fall. I'm going to try to jump start it with my truck in the morning and see if a little bit more amperage, and faster cranking, will make it start. If it doesn't start, I think I have a compression problem. I have fuel, I sure should have glow plugs functioning (brand new glow plugs and voltage), so if it doesn't start with a jump start, what else could it be?

 

[SilverLakeFab]

I decided that I am going to get to the bottom of this and just ordered a compression tester. Next I need to find out what a good compression rating will be for this machine. I'll post my findings.

 

[aczlan]

Silly question here, but is the fuel shutoff lever is in the run position (if that tractor is like our B7500 which has one)? That has gotten me several times on our B7500.

Aaron Z

 

[SilverLakeFab]

Hi Aaron Z,

I was wish this one were that simple. The fuel is on and the injectors are getting fuel, which I have verified by cracking the injector lines to bleed them a second time just in case. Still no dice though. I'll let everyone know what I find with the compression test later next week. The compression tester should arrive on Thursday.

 

[aczlan]

I decided that I am going to get to the bottom of this and just ordered a compression tester. Next I need to find out what a good compression rating will be for this machine. I'll post my findings.

IIRC compression should at least 400PSI (less than 400 and it probbaly wont fire) and all cylinders should be close (ie: readings of 450PSI, 444PSI and 300PSI would indicate a problem with the 300 PSI cylinder).

Aaron Z

 

[SilverLakeFab]

Thanks Aaron Z. I thought that the compression should be in the 400 PSI range. At this point, as far as I can tell, all I have left is a compression problem. I knew when I bought the machine last year that I might be in for that, as the vent hose that goes from the top of the valve cover to the bottom of the machine was blowing out some white smoke after running the machine for a little while. I think that may be an indication that there's some valve blow-by. Once again, I think. I'm no certified diesel mechanic.

 

[aczlan]

If you put your hand over the exhaust pipe while turingin the engine by hand, you should be able to feel when each cylinder starts dumping exhaust.
I am not sure where the recommended PSI is be on a Kubota engine, but the VW engines I have worked with recommended the following (in the words of a friend who rebuilds Volvo D24 engines):

700+ It don't get no better than this.
650 Excellent
600 Very good
550 Good
500 Fair
450 Poor
400 Bad
350 It ain't gonna start

Aaron Z

 

[TCJatko]

If you put your hand over the exhaust pipe while turingin the engine by hand, you should be able to feel when each cylinder starts dumping exhaust.
I am not sure where the recommended PSI is be on a Kubota engine, but the VW engines I have worked with recommended the following (in the words of a friend who rebuilds Volvo D24 engines):


Aaron Z

Are you sure about those pressures? I always thought a diesel engine should be in the 350-400 psi range (gas engines usually go about 125-150 psi). The 700 psi reading would indicate a CR of roughly 50 to 1.

 

[Buckgnarly]

Timing could also be an issue besides compression.