This is an old topic, but I hope I can revive it to answer a couple questions.
I have a 1990 GMC 366 bus on propane with a 5speed manual transmission and I looked on the carb to see the govenor itself, I noticed in other threads that this two wire connector can be spliced to stop the govenor effect.
When I was driving the bus home, on purchase day, I found that it had no power and we had to work just to get it up to 60 mph. I live very close to the mountains and I found that when I approached a hill at WOT ( 60 mph )it didn't have the power to make it up the hill and powered down to 40mph.
I love the govenor idea for shifting without regard for needing a tachometer, so I thought an easy solution would be to install a toggle switch that I can flip on the highway to shut of the govenor to take "a run" at hills. The other choice is to find a 3700 rpm govenor and swap out the old one, but heck I can't find the control box under the hood or something on line for suppliers or a picture of a box to look for
I have done a complete tune-up and found that the air filter was plugged, one plug wire was burned through on hole 4 and hole 8 had a very wet electrode to tell me it wasn't firing properly. I replaced the bosch platinum plugs with AC Delco platinum plugs gapped at 45thou. Replaced the burned through wire and the air filter.
I am waiting on a new propane tank that will arrive Monday, so I haven't checked the performance since the tune-up. I am also going to recheck the rest of the plug wires,change the cap & rotor and double check the timing to ensure proper advance.
If any of you can tell me how your 366 5spd propane buses perform for climbing hills it would be appreciated! Any tips on timing advance on your propane bus would be a huge help as well.
I think the powering out was due to the mistuned condition, but I still wonder that with the bus capped at 3200 rpm, if it might still be underpowered for mountain trips. I am not a speed demon by any means, I am more concerned about safety as my bus dies out and people are forced to hold up or pass me unsafely.
So can the govenor be toggled and do the buses have more power than what I experienced?
p/s first post btw