Is this a Briggs clone? And a general question re. fuel solenoid valve.

[louky1150]

I am helping a neighbor with a no start, and leak condition on a neglected 5500w generator. It is an UST model. I verified the carb is completely junked up, the threads on the bowl retaining nut are missing, and the petcock filter in the tank was broken off. I've ordered a carb and new petcock.

The carb has a solenoid on the bowl which was gummed up and stuck in the short position. I got it freed up, it is spring loaded so it's normal position is the retracted position ( I assume unseated). I have had some experience with these but only on riding mowers with a battery. The generator doesn't have a battery so how the heck does the solenoid fit in the picture? Also, there is some sort of (I assume) vacuum activated valve located on the bracket that contains the choke linkages. There is a small hose the runs from this valve to a black block located behind the carb next to the block. You can see this hose and block in the pic. Can someone explain the function of this valve? My first generator so I appreciate the help!

 

[MParr]

Chinese clone, possibly of a Honda.

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[ILENGINE]

The vacuum is to open the choke upon starting kind of like the choke systems that was used on car back in the 70's. and the solenoid on generators are normally held in the open position and when the generator is shut off the winding supply power to the solenoid to push it shut and then the windings stop turning the solenoid is returned to it open position. Does the same thing as the one on the riding mower but works in the opposite direction. Instead of needing power to open like on a rider it requires power to close it.

 

[louky1150]

ILENGINE: Thanks for the prompt reply! Both things make sense now. I will need to make sure that the linkages on that choke system are free and lubed. I was having trouble getting my head around the solenoid but I see it now.

 

[artemjemmy]

ILENGINE: Thanks for the prompt reply! Both things make sense now. I will need to make sure that the linkages on that choke system are free and lubed. I was having trouble getting my head around the solenoid but I see it now.

The fuel shut off solenoid on these generators is different from other small engines. Yes, you are correct, it allows fuel through when it is unpowered, but when it is powered, it blocks fuel flow. This works because when you turn the engine switch to off, it sends power from the generator that is still spinning to the solenoid valve, which closes and prevents fuel flow into the carb, stopping afterfire due to spark being cut out already from the stop switch. When the generator slows down enough that it can't power the solenoid anymore, it opens again. As a result of these, generators with a fuel solenoid can't just use a simple stop switch and need a big multi-pole switch instead.