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Hello all,
First post on this BBS
I purchased a 72 SIII a few weeks ago in pretty good original shape. Mechanically, it is sound, with about 8K miles on the engine, trans, carb, radiator, exhaust.....etc....
It came from about 1000 ft altitude, and now lives in Colorado at 9100 ft altitude. It started and idled fine, but (not expecting a rocket), foot to the floor acceleration was not great.
I figured the jetting on the carb and maybe the timing, so here is what I have done:
-checked the dizzy, which I found to be converted to electronic ignition.....then set the timing to about 12 BTDC
-checked the plugs, which were a nice color, but the gap was a bit off (my .034 guage could easily fit in the gap), so I regapped to factory specs using my .030 guage
-cleaned and refilled the oil bath filter
-jet-wise, Pierce Manifolds seemed very knowledgeable, and suggested a one step down idle jet (50 to a 45); from my main jet of 165 to either a 155 or 160; and an increase in the air correction jet from (I think) 190 to 200
It fires right up, even in the very cold weather we are having, and idles well. I think the acceleration is better, but perhaps I leaned it out a hair too much, so I might try the 160 main instead of the 155 I went straight to.
So, at 9100 ft altitude with a Weber ICH on a petrol 2.25, does my route taken seem sound? Timing right, or a bit more advance? Seems a few people at altitude are using 12 BTDC, but I have heard other variations....including a degree of advance for every 1000' above sea level, which running premium gas, theoretically puts me at 6 BTDC per the manual PLUS an extra 9 degrees to 15 BTDC. Concerned about pinging there.
Thanks for any thoughts....
Julian
First post on this BBS
I purchased a 72 SIII a few weeks ago in pretty good original shape. Mechanically, it is sound, with about 8K miles on the engine, trans, carb, radiator, exhaust.....etc....
It came from about 1000 ft altitude, and now lives in Colorado at 9100 ft altitude. It started and idled fine, but (not expecting a rocket), foot to the floor acceleration was not great.
I figured the jetting on the carb and maybe the timing, so here is what I have done:
-checked the dizzy, which I found to be converted to electronic ignition.....then set the timing to about 12 BTDC
-checked the plugs, which were a nice color, but the gap was a bit off (my .034 guage could easily fit in the gap), so I regapped to factory specs using my .030 guage
-cleaned and refilled the oil bath filter
-jet-wise, Pierce Manifolds seemed very knowledgeable, and suggested a one step down idle jet (50 to a 45); from my main jet of 165 to either a 155 or 160; and an increase in the air correction jet from (I think) 190 to 200
It fires right up, even in the very cold weather we are having, and idles well. I think the acceleration is better, but perhaps I leaned it out a hair too much, so I might try the 160 main instead of the 155 I went straight to.
So, at 9100 ft altitude with a Weber ICH on a petrol 2.25, does my route taken seem sound? Timing right, or a bit more advance? Seems a few people at altitude are using 12 BTDC, but I have heard other variations....including a degree of advance for every 1000' above sea level, which running premium gas, theoretically puts me at 6 BTDC per the manual PLUS an extra 9 degrees to 15 BTDC. Concerned about pinging there.
Thanks for any thoughts....
Julian
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