governor problem?

[fabricator]

OK so I have my roid running a lot now and I have an annoying apparently governor problem, it'll be sitting there purring away and for no apparent reason slow down so far some times it seems like it's gonna quit but it never does, this does not seem to correlate in any way with the load on my alternator, it runs into my battery bank first anyway.
I have replaced the original spring with a new slightly stronger spring, I also ran small springs between all the governor linkages to eliminate all slop, it does this every 6-8 minutes like clockwork, I'm out of things to try.

[vdubnut62]

Watch the linkage, see if it's opening up the rack when it slows down, if it is then you don't have a gov problem.
At that point I would start looking at fuel starvation, sucking a gulp of air into the line, line collapsing ,etc.
Ron

[Ronmar]

I agree, what is the rack doing during these RPM droops.  The spring should pull the rack open with any RPM decrease.  If it is opening, but RPM is not increasing it is either overloaded, or the engine power output is reduced possibly from fuel starvation or air intrusion as vbub noted.  If the rack is not moving, perhaps one of the linkages is binding and preventing a response to a load change...

[dieselgman]

I would start with ensuring that the whole governor setup is very smooth and all connections evenly snug everywhere. Any sticking points might be fairly subtle but can cause a variable governor response at the pump rack. Also be certain that your fuel-pump rack is very smooth in operation. Sometimes some poorly finished parts can make it through the assembly and testing process and yet have some flaws that manifest the way you describe. The linkages are sometimes bent or deformed either in shipping or assembly. This can happen to the external parts easily and somewhat less so on the internals. I believe that a lot of people have resolved sluggish or wandering governor issues with changing the springs as you described... It might be good to take a search through the LEF on that topic, I tend to forget the details sometimes...

Best of luck!

dieselgman

[fabricator]

Ok, I'll go through the linkages and rack with a fine toothed comb, there are no air leaks, I have semi clear fuel lines, I could see air in the lines.

[akghound]

How is your fuel filter?
Ken Gardner

[dieselgman]

I also agree 100% with the possible fuel starvation issue!

If your rack is smooth, what happens if you manually move it when the engine rpm is dropping off? If it immediately comes back to speed, then it would indicate a 'lack of governor response' related issue and most likely culprits are the linkages. We've seen a lot of them bent out of shape.

dieselgman

[fabricator]

How is your fuel filter?
Ken Gardner

My fuel filter is a modern filter from TSC about 6-7 inches tall, it should be good for a year.

[fabricator]

I also agree 100% with the possible fuel starvation issue!

If your rack is smooth, what happens if you manually move it when the engine rpm is dropping off? If it immediately comes back to speed, then it would indicate a 'lack of governor response' related issue and most likely culprits are the linkages. We've seen a lot of them bent out of shape.

dieselgman

I was messing with the rack last night and I can move it 1/4" both ways with no effect on rpm, when I watch it closely the governor arm is basically in constant motion one way or the other moving in very,very small increments until it has one of the large movements and slows way down.
I never really did anything with making sure the pump timing is perfect could this be a reason for this?

[Carlb]

moving the rack 1/4" should make a very large difference in the rpm of the engine. I would venture to say the fuel pump may be starving for fuel.  As mentioned before check to make sure the fuel filter is not clogged.

[fabricator]

I'll get a new fuel filter tomorrow so that can be ruled out.

[dieselgman]

Right, any movement in the rack must make a corresponding large change in engine speed! If that issue turns out to be the pump itself, we have them in ready supply as well as the elements to rebuild. Confirm your fuel supply is good, and then we can proceed with more drastic measures as needed.

dieselgman

[Geno]

A ¼" of rack movement each way is a lot so take this with a grain of salt.
A number of people, including me, have reported the same issue and the general consensus is a temporary lack of fuel. I checked everything on mine but the only thing that made a big difference was to stop mixing 10% rug in with the WVO, especially during the summer. Seems like there were vapor bubbles in my heated hp fuel line. How can that happen to fuels under those pressures? No clue, but switching to 15% red diesel made a big difference.

Thanks, Geno

[squarebob]

When your rack has one of its large movements, and you loose RPM, is the rack moving to a "give me more fuel" position, or "give me less fuel" position?

Bob

[fabricator]

I'll have to check that out.