BX1800 Starting Issue

[mwechtal]

I have a weird problem starting my BX1800. The gist of it is that it will not start while cranking, but as soon as I release the key it will usually start after a few tries.

Does anyone have any clue what might be wrong?

Mike

 

[David_Kb7uns]

Do you hear the clicking of the fuel lift pump when key is on before cranking?

David Kb7uns

 

[mwechtal]

Hmm, I think so, but I'm not sure. I'll check that tonight.

Mike

 

[unbidden]

New glow-plugs may help.

 

[SPYDERLK]

Some problem with the fuel cutoff valve. It should be held open anytime the engine is running or cranking - then closed to stop the engine. This is done electrically by the key switch and is somehow faulting in the crank position ... OR the valve is sensitive to the reduced voltage during cranking. Trace the electrical connections. Something may be loose or corroded.
larry

 

[mwechtal]

Yeah, I just checked, and the fuel pump runs, at least before I start cranking, but the battery seems a little anemic. Fully charted it's just barely over 12v, and it sags to 11.5 or maybe just under while cranking. That's not low enough to say a cell is shorted, but it's not what I expected.

So, my next step is to try jumping it, and checking all the connections. That valve just may be closing until I stop cranking, and then it starts on the momentum from cranking.

 

[David_Kb7uns]

Some problem with the fuel cutoff valve. It should be held open anytime the engine is running or cranking - then closed to stop the engine. This is done electrically by the key switch and is somehow faulting in the crank position ... OR the valve is sensitive to the reduced voltage during cranking. Trace the electrical connections. Something may be loose or corroded.
larry

Most small Kubota engines only energize the solenoid for SHUTOFF of the fuel supply. No power to solenoid for run condition.

Look at the solenoid when cranking to make sure the solenoid timer circuit is not kicking in because of low cranking voltage.

Does it start ok when engine warm?

It either is not enough cranking speed, lack of preheat from glow pugs or loss of prime from lift pump to injection pump


David Kb7uns

 

[SPYDERLK]

Most small Kubota engines only energize the solenoid for SHUTOFF of the fuel supply. No power to solenoid for run condition.

Look at the solenoid when cranking to make sure the solenoid timer circuit is not kicking in because of low cranking voltage.

Does it start ok when engine warm?

It either is not enough cranking speed, lack of preheat from glow pugs or loss of prime from lift pump to injection pump


David Kb7uns

OK, good. Thanks! But it starts just as he lets off the key. The fuel is right there at the injectors but not getting to the cyls while cranking. There seems no realistic explanation.
larry

 

[David_Kb7uns]

Just for fun take off the fuel line from the filter by the injection pump and turn the key on to see how much fuel you have coming from the lift pump. You can also check the stop lever connected to the solenoid to see if it is free, have also heard of weird things happening when the spring inside the injection pump failed.

David Kb7uns

 

[mwechtal]

Most small Kubota engines only energize the solenoid for SHUTOFF of the fuel supply. No power to solenoid for run condition.

Look at the solenoid when cranking to make sure the solenoid timer circuit is not kicking in because of low cranking voltage.

Does it start ok when engine warm?

It either is not enough cranking speed, lack of preheat from glow pugs or loss of prime from lift pump to injection pump


David Kb7uns

That gives me some more things to check. I guess I have to pull off the shrouds to see the guts. I miss my B7100 at times like this. Everything just hung out where you could get to it.

By the way, it starts easier when warm.

Thanks
Mike