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Q regarding fuel solenoid valve

PostPosted: Thu Oct 21, 2010 4:43 pm
by Jeff Bowers
Hi,Dave and Ruth. I've got the new Kubota in and up and running. It's a nice
> piece of gear and should be good for many more years. Thanks for getting
> it for us. My 1 problem is that it is indeed running, but not stopping.
> The fuel solenoid valve shuts properly but the engine keeps running for at
> least a couple of minutes. I installed the valve by mounting it on a
> bracket connected to the intake manifold with a short hose of about 3
> inches in length leading to the injector pump input. Presumably the
> injector pump has a strong enough draw to continue to pull remaining fuel
> from the short hose even though the valve is closed. Since I've never
> seen a modern Genie with this solenoid valve on it, I don't know how it
> should be installed, and presumably I've done it incorrectly. Can you
> tell me, or is there any documentation to show me, how it should be
> installed so that the shutoff is instantaneous? I've looked and pondered
> but I just don't see how to do it with the valve securely fastened. I'd
> much appreciate any help or advice. Thanks again for getting this for us.
> It was definitely the right solution.
> Regards,
> Jeff Bowers

Re: Q regarding fuel solenoid valve

PostPosted: Fri Oct 22, 2010 10:29 am
by Coulomb
How long the engine runs after the fuel solenoid is closed depends on how much fuel is in the line, (length), and how flexible the hose is. Suction from the injector pump is able to pull a little fuel from a 'soft' hose and all it takes is a little fuel to run for a minute or two.

However, there is an upside to this. The raw water pump is shutoff, so the engine gets a chance to clear out raw water that might be lingering in the exhaust outlet.

The old fuel lever solenoid got to be too unreliable after the manufacturer started production overseas.

Re: Q regarding fuel solenoid valve

PostPosted: Fri Oct 22, 2010 11:03 pm
by Jeff Bowers
Thanks, Coulomb, for your quick response. To test the minimum shutdown time I directly connected the solenoid valve output to the injection pump input w/ no intervening hose or connection, minimizing the fuel available to the pump after the fuel valve shut down. It still ran for nearly half a minute. It seems that this is a disaster waiting to happen. If oil pressure fails for some reason and the oil pressure switch opens, the engine continues to run for what would appear to be ample time for major internal damage up to possible complete seizure. This happened once on the previous engine: the oil seal in the crankcase opening for the optional hand crank blew out and spewed out 2 liters of oil. The OP switch opened, and the engine shut down immediately as the throttle solenoid released the throttle. The engine room was a disaster but the engine was undamaged. Had it been controlled by the fuel solenoid valve instead of the throttle control solenoid, it would surely have seized up. For this reason, I feel very doubtful about the safety of the current mechanism. Is there something I'm missing?


Jeff Bowers

Re: Q regarding fuel solenoid valve

PostPosted: Sat Oct 23, 2010 12:31 am
by Coulomb
I think the engine has enough oil in the bearings to survive that long, but here's a way to stop the engine quickly.

You could do what we do with the EnerMatic Controller: turn off the fuel solenoid with the regulator still on. It will stall the engine.

The best way to do that in your case is to rewire the regulator on/off switch so it doesn't get power from the Run Switch via the Genie Controller. The low oil pressure switch or hot water switch will turn off the fuel solenoid as usual. Just remember to turn off the regulator after the engine stops.