JKM

If there is a stuck plunger/barrel in say a P pump for example, it will hold the rack at that setting, because it is stuck and cannot turn, therefor holding the rack at whatever fuel setting it is on when it sticks, at this point the goveroner DOES NOT have control anymore. The definition of a runaway that I grew up learning was fuel from an "uncontrollable" source , not an "external" fuel source. Once that rack is stuck and out of control of the goveroner , it just became an uncontrollable fuel source, think about it for a minute...

1-5-3-6-2-4

I disagree, it will never exceed what it sticks at, yes it is uncontrollable, but still unable to exceed that limit. its not a runaway. runaway has no controlled maximum. so the engine will run up to physical destruction.

I didn't grow up learning anything, I was taught at a Technical college

JKM

What would you call that scenario then? You can not shut it off with a stuck rack unless you cut the air off. It is a runaway, your just not thinking about it... Just because it will not free rev until destruction doesn't mean it is not a runaway , a runaway is an engine running on an uncontrollable ungoveroned fuel source, a stuck rack is no longer controlled by the goveroner... think about it and you will understand.

I Learned as I was growing up , AND went to technical college, a couple of them infact.

logskidder

THIS IS GOING NOOOOOOOOOOOOOOOOOOWHERE

1-5-3-6-2-4

I totally agree. but a basic fact of engine governance is being overlooked.....in that previous scenario.........What is limiting the fuel flow to the engine????


The fuel is being governed........so the engine will NOT freerun out of control. So the engine is governed. Its that simple.

logskidder

You guy's are more stubborn than my Edit girlfriend..................I need a beer

JKM

So if I just have a SMALL engine oil leak into the intake , and it is not enough to cause the engine to exceed governed RPM then i must not have a runaway , because the size of the leak is governing the engine? Thanks for the enlightenment.

1-5-3-6-2-4

no you're still not getting it. You apparently do not understand how a mechanical unit injector works.

Hayseed

What was the original question again?????????????

logskidder

I think the og poster may have been dealing with a stuck rack or gov issues.

wcbcruzer

No seriously, what was the solution to the main problem?

JKM

I know exactly how an MUI works. What does that have to do with the scenario of a stuck plunger/barrel assembly in a P pump.


If an MUI without a spring loaded rack sticks , they all stick , that's what the air shutoff is for, the engine will NOT free rev past the goveroner in that situation , but the govoner is still NOT in control of the engine , the stuck MUI is holding the rack in whatever fuel position it stuck in.

If there is a spring loaded rack just the stuck MUI will stay at whatever fuel setting it is stuck on , the rest can be turned to Zero fuel to shut down the engine.

1-5-3-6-2-4

Last try, its the fuel metering device that fuel has to bypass in order to have a runaway. In a 2 stroke detroit, the metering in the unit injector has to be bypassed, on a 6b bosch P-series its the port helix.

Fuel has to bypass the fuel metering devices in order to have a runaway. Not the fact that the operator has no input to the metering device. If fuel is flowing through the port helix or through the metering device in a unit injector. Fuel is still being metered to the engine.

Governor springs and flyweights balance operator demand to engine load, and set min max rpm. Those taken out of the equation, still has fuel entering the engine through the metering device, although the metering device may be stuck at whatever position.

Does any of that jive?

Lunyfringe

this thread has lost it's ability to be governed...

Diesel Dave2

Sure sounds like the same thing happen to me...When the truck seemed to stall and I pressed on the clutch and the RPM went to 3600...