Zorba's JeepJeeps, and most trucks, can benefit from a hand throttle. My beloved '63 GMC 1 ton that I grew up with had one, and they're a very popular addition on Jeeps. They act like a sort of very low speed cruise control and/or as a "base RPM" that can be further feathered with the pedal. They're also great for increasing idle RPMs for PTO use, hot weather idling, and increased battery charge when using an electric winch. Of course this Jeep doesn't have PTO capability - which is rather unfortunate - but the rest of the reasons still apply!
Many Jeepers use what amounts to a bicycle shift lever that is mounted to the transmission shift lever. This bicycle part controls a cable that manually controls the throttle. An excellent setup by all accounts, especially for rock crawling. However, I'm very "old Skool" for one, and for another, I won't be doing much rock crawling with this Jeep (in Florida?). The bike lever allows rock crawlers to easily alter throttle position dynamically with their transmission shift hand. I decided to go "old Skool" and install an "old Skool" pull out style. Maybe I'll change my mind later, but for now that's what I've done:
Figuring out how to install something like this is non-trival what with today's modern plastic dashes. It would have been considerably simpler in a YJ or CJ which had "real" dashboards of metal, rather than the TJ style that looks like it was borrowed from a minivan. Still, once thought through, it wasn't bad. There is a metal frame at the very bottom of the dash, I drilled a 5/16" hole through the plastic and through the metal frame, being VERY careful not to drill into any wiring! The metal frame at the particular location used, is semi-triangular, with the plastic forming a slightly curved base. I was able to use the dingus pictured above as a shim to support the plastic and allow correct tightening of the bolt with its nylock nut. The bolt tightened up nicely, the impromptu shim worked well, and the modified nut I used as a bushing in the angle keeps everything from sliding around. I didn't have to wail on the bolt either, its just snugged up, but the bracket is nice and stable without stressing the dash plastic.
Hand throttle assy with Ell bracket. I think the bracket came
from my late Father, it looks like a "unistrut" bracket.
After paint. Note I switched from the short to the long side for the hand throttle assy.
Using a 5/16" bolt, the 1/2" hole was way too big. A 5/16" nut got modified into a bushing!
I needed to drill a hole in the very bottom of the dash. As I had not exercised
this little genset in several months, I decided to power my drill with it.
Bolted up. I ended up using a 2 inch long bolt - the 1-1/4" long bolt shown above was too short!
I used this as a shim under the plastic. See text.
View from operator's position.
Location to bring through firewall. Good location, optimal angle.
⅜" hole drilled and primered.
Hand throttle cable, RTVed in place.
Coiled up temporarily...
Main and cruise control throttle cables and the bracket the holds them.
Hand throttle cable added to new hole and ferrule.
Hand throttle cable routed similar to the main throttle cable.
Chain linkage allows other throttle cables to actuate - the
hand throttle cable doesn't move back in like the other two do.
That's the good news. The bad news is that the hand throttle didn't seem to like the multiple bends in its routing - at first it was hard to actuate, then it became stuck and could not be pulled out.
Next phase - eliminate the worst of the bends with this "Speedway" bell crank lever.
Existing tapped hole in bracket might be a good place to locate it.
However, trying to tap it out to ¼" failed with a broken tap! Completely my
fault, I should have pre-drilled it although I've "gotten away with it" before.
Despite heroic attempts to remove the broken tap, I ended up cutting the
backing nut off with a cutoff wheel after removing the bracket from the Jeep.
Re-installed after drilling an extra ¼" hole, and repainting the entire bracket.
Bell crank lever shortened and installed...
... using spacers made from ¼" NPT pipe. Both cut down to the shorter length (R).
This cable may need to be rerouted, but most likely not.
How it gleams in the morning sun!
Cable/chain combo connects to throttle.
Bell crank lever configured to its final state, additional bracket &
hardware obtained and installed, then the vastly shortened cable was attached.
Handle inside pulled out activates the bell crank lever which activates the main throttle.
Unlike previously, the hand throttle now works very easily and smoothly.
Update: During the "cold" Florida winter, the idle speed of the Jeep increased to
about 1200 RPM inexplicably. Turns out, I had the hand throttle adjusted a bit too
tight - the cold caused the cable to contract, actuating the throttle slightly. I made
an approximate ¼" adjustment to the hand throttle cable which fixed the problem!
Handle pulled out inside.
In other news, a rubber pad was acquired for the floor jack...
... but it needed this wooden spacer to re-enforce it.
Read on for the next part!