MEP805B Engine Control Prime & Run position

[Raptor01]

Does anyone know what happens when the generator control switch is placed in "Prime & Run" position prior to starting the generator? Should I hear something start to run like a fuel priming pump? Couldn't find a description of this switch position function in any of the Tech Manuals.

 

[Guyfang]

Yes, you should hear the electric fuel pump come on. It should slow down/stop when it has primed the system.

 

[Raptor01]

Yes, you should hear the electric fuel pump come on. It should slow down/stop when it has primed the system.

Thanks for replying. I don't hear anything come on. Where is the electric fuel pump? Can you point me to a figure in the tech manual? I need to make sure it is getting voltage.

 

[peapvp]

Does anyone know what happens when the generator control switch is placed in "Prime & Run" position prior to starting the generator? Should I hear something start to run like a fuel priming pump? Couldn't find a description of this switch position function in any of the Tech Manuals.

Is your Master Switch S3 in On or Off Position when you place the Engine Control Switch S1 in "Run &Prime" ?

 

[Guyfang]

Wait!!!!!!!!!!!!! No you should NOT hear anything. Sorry, I was helping someone with an MEP-005A, and just kept thinking about a different gen set. Sorry, one hundred times. All you have is a hand operated primer hand pump. There is an AUX electric fuel pump. But no other electric fuel pump.

Tell us what problems you are having.

 

[Raptor01]

Is your Master Switch S3 in On or Off Position when you place the Engine Control Switch S1 in "Run &Prime" ?

Hello.

Is your Master Switch S3 in On or Off Position when you place the Engine Control Switch S1 in "Run &Prime" ?

Hello, Master Switch is in the On position. BTW, the generator starts and runs fine. Just wondering what happens when the switch is in the Prime & Run position. The TMs just say to place the switch in this position. It does not tell you what to check for.

 

[Raptor01]

Wait!!!!!!!!!!!!! No you should NOT hear anything. Sorry, I was helping someone with an MEP-005A, and just kept thinking about a different gen set. Sorry, one hundred times. All you have is a hand operated primer hand pump. There is an AUX electric fuel pump. But no other electric fuel pump.

Tell us what problems you are having.

Thank you. The generator runs fine after a fuel pump rebuild ($1500 in California). Just wondering what happens when the switch is in the Prime & Run position. The TMs just say to place the switch in this position. It does not tell you what to check for.

 

[Guyfang]

The prime and run position.
With the engine off, all the run circuits are energized. It doesn't prime anything, as there is no electric fuel pump.
With the engine ON and running, All run circuits are energized, and the set operates.

This position is where the S1 will spring back to, after you start the set, it comes up, makes power, and you let go of the S1. This is the normal position for S1 to be in. The only other time the S1 is in another position during operation is the AUX/Run position. That's used for running off a separate fuel supply.

 

[Raptor01]

The prime and run position.
With the engine off, all the run circuits are energized. It doesn't prime anything, as there is no electric fuel pump.
With the engine ON and running, All run circuits are energized, and the set operates.

This position is where the S1 will spring back to, after you start the set, it comes up, makes power, and you let go of the S1. This is the normal position for S1 to be in. The only other time the S1 is in another position during operation is the AUX/Run position. That's used for running off a separate fuel supply.

That clears it up for me. I assumed it was priming something because it is labeled "Prime & Run". Like they say, assuming makes an ass out of you and me

 

[peapvp]

This is interesting,
as per -14 Manual we have three fuel related pumps:

1. Transfer Pump
2. Injection Pump
3. Auxiliary Fuel Pump

I am sure this must be utterly confusing to the innocent bystander and new owner of a 805/806 Bravo Unit

I am sure @Guyfang can explain in detail on how each of these pumps are operated and functioning

 

[Guyfang]

The transfer pump, is a Lever/Arm driven pump.

Injector pump needs no explanation.

The AUX pump is only used to transfer fuel from a secondary source, to the generator fuel tank. When the fuel tank is full, a fuel level switch cuts the power off, and the AUX system is disabled, until the set fuel tank once again is mostly empty.

 

[Guyfang]

Everyone misses the Transfer pump, because it part of the engine. Look at TM 9-2815-255-24P, Figure 16, Item 24.

 

[Raptor01]

Everyone misses the Transfer pump, because it part of the engine. Look at TM 9-2815-255-24P, Figure 16, Item 24.

My unit has a John Deere 4045TF151 so fuel transfer pump is in TM 9-2815-259-24P, Figure 19, Item 1.