1964 challenger

[toomanytoys]

Just bought this 64 mci challenger runs great and drives great but has intermittent lack of power and top speed capabilities.  Changed both fuel filters and cleaned all the air filters with new oil , greased up the solenoids for the throttle on top of engine and still not performing on consistent basis.  Wondering about the throttle pedal and if it has some sort of adjustment and if it only has a certain range of movement that it works at , like it's not supposed to go all the way to the floor? Thanks appreciate any help

[Dave5Cs]

Top speed on the flats maybe 68 to 62 is normal with pedal to the floor. Going up a steep grade 17MPH with pedal to the floor and in 1st gear.
6V71 Non turbo automatic 644. MCI 5C.
If you have a larger engine maybe more but not much.

[toomanytoys]

having trouble getting over 45 on flat ground when it decides it doesnt want to respond.

[luvrbus]

Some time when the skinner valve that works the shut down on the engine, will leak and let the shut down activate a little and you don't get full power or throttle, common problem on a MCI ,then the governor air gap could be out of adjustment also causing the problem

[toomanytoys]

how do i go about testing these parts ?
how do i check and adjust the governor?

[luvrbus]

The shut down is easy just disconnect the air line and plug the hose and go for a ride,check the cylinder 1st there should be a clearance between the cylinder rod and the shut down arm when running, Setting the air gap is a different ball game .If you haven't have a body push the pedal and you check to see if you are getting full pedal on top of the governor by pushing on the lever where the throttle connects

[toomanytoys]

Is this the shut down ?

[luvrbus]

That is the skinner valve ,the shut down is on top of the governor it will have a cable for the pedal there too 

[Satelliteguy]

We use to take if we had a little over heating we would put a thumb tac in the air line to the skinner valve to stop the air from shutting it off. Just have to really watch the heat gauge so you don't cook a motor.

[Coach_and_Crown_Guy]

Is this the shut down ?

Yes. The Skinner valve is the electric solenoid and the small air cylinder actuator to it's
right is what pushes on that short lever arm coming out of the top of the governor. That
is the actual shut down lever and you can easily move it by hand anytime. As long as
there is a gap between the shutdown lever and the air actuator push rod you are not
experiencing any shut down lever overriding the governor issues. Your problems lie
elsewhere.

It's also a very good idea to check thoroughly the throttle linkage from the front to the
back to ensure you're getting full travel all the way to the throttle lever on the governor.
It's pretty easy to have accumulated sloppy lost motion prevent the throttle lever from
hitting the full throttle position. Age and rushed mechanics through the years will usually
make this problem hang around and get worse with time. Don't trust anything until you
get in there and verify all the motion from the throttle pedal to the throttle lever on the
governor is being transmitted fully. Once you get this right the bus will seem to have a
new lease on life and you can control it much better with a smooth and responsive pedal
again. Knowing that you are actually achieving full throttle when you need it will give
you confidence and even may cause you to notice other subtle little problems previously
being masked by the sloppy linkage and not hitting full throttle. In case I haven't been
clear the throttle lever is the one just to the right of the shut down lever. It's the one
with that cable end attached to it. I Strongly suggest that you make the effort to acquire
an engine book for it which you can find for reasonable prices on ebay. It will explain
it for you in great detail and help you gain confidence in your own knowledge on what
to do and how the parts work together. The same goes for the MCI book too. You need it.

If this doesn't fix the problem then you have something wrong in the governor and control
rack systems inside the heads. This will require a seasoned DD 2-stroke mechanic who
can troubleshoot and repair whatever is going on. There can be many reasons and only a
qualified DD engine guy should be allowed to open it up and diddle around with your
engine and governor, or you could end up with many more problems than you have now.
You've been warned. Good luck.

[toomanytoys]

Would have been nice to know this also is what shuts the engine down , unhooked and coupled the lines like you said and it made no difference in the test drive till I got back and couldn't shut the motor off and with my switch off it started smoking super bad .and now won't fire up right or shut off with air lines connected to the skinner

That is the skinner valve ,the shut down is on top of the governor it will have a cable for the pedal there too

[luvrbus]

How many air lines did you disconnect sounds  you have the air lines crossed the smoke is because you tripped the emergency air shut off