I'm investigating a lack of power (and popping) which occurs on my tan pinz with stock transmission. I have a green pinz as well which is blessed with the high speed transmission and when comparing the two - the green pinz out performs in both acceleration and top speed. The top speed makes sense, but the acceleration seems like it should be won by the stock transmission. So, Tan Pinz seems to lack power and substantially hesitate while Green Pinz can really move.
My first guess was stock ignition vs civilian. Civilian conversion did not make any change. I have it timed at 9 degrees on the nose. I have bypassed the 4500 RPM module and have 18v at the positive side of the coil.
Next guess was the good ol carbs. I have them perfectly matched albeit they draw a bit more air than they should at 950 rpm (10-11 on the gauge). Idle is fantastic. They do not leak onto the butterflies nor on the outside as best as i can tell. I tried spraying brake cleaner on the carbs and intake manifolds below the cover and saw no change in idle speed.
I checked compression today after adjusting cyl # 1 and 4 exhaust valves (they were too tight) and wound up with 120, 120, 130, 120. Not the best, but not horrible by any means. I checked exhaust manifold temperature and found something rather interesting. In order - 400, 340, 340, 240. Cyl 4 appears to be running much cooler than the others but all spark plugs appear very clean. They have a tiny bit of white ash to them if anything.
Have i eliminated all other possibilities beyond the carbs? Are there other variables to check before concentrating on the carbs? Is it possible that fuel pressure may not be sufficient at acceleration and if so, how would i check? There are no red flakes by the way and i can maintain 55 MPH no problem.
My next step is to swap the carbs between trucks and check for changes. If the problem follows the carb, time for a rebuild. if not, i'm stumped!
