| Going to Colorado High Altitude?
Hey there, I own a 1973 (Early-{March}) FJ40 (w/ rebuilt factory "F" engine). I am using a Weber 38DGas carb with the smallest jets that Weber sells (I think they're .028" or .026").
I live in the mountains just west of Denver at 8550' and I still run a little rich. Whenever I go 4-wheelin' I always take my timing light to adjust my timing while on the trail. The factory timing (at sea-level) is 7˚-8˚ BTDC, but at my altitude I have found that 9˚ BTDC is perfect until I get to about 11,000', then I have to change the timing to 10˚-11˚ to get the same performance. You must also turn down the fuel-air mix all the way, and you will still be running a slightly rich fuel mix above 12,000'. I keep my fuel-air mix turned down almost completely! Another good tip, before you go to altitude above 8,000' install and correctly gap a brand new set of ignition points, this will help a lot!
WARNING-DO NOT EXCEED 12˚ BTDC!! SERIOUS DAMAGE TO YOUR VALVES CAN OCCUR!!!
The timing is the same for both engines, however the best way is to just experiment a little on the trail to find that "sweet spot" for your particular engine for the current conditions (I've had my engine start to run like crap at 12,000' when a very strong thunderstorm {even lower barometric [air] pressure} has moved overhead, and the last place you want to be during a bad thunderstorm is at high altitude or above treeline!!!). I also have to adjust the timing a couple of degrees for the winter when it's extremely cold out (my cruiser is also the best snowplow vehicle I've ever had). Good luck! Maybe I'll see you on the trail out here! | 
08-30-2007, 06:27 PM
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