Join Date: Jan 2002
ooby <BLOCKQUOTE>quote:</font><HR>Originally posted by Everett#2390:
First things I'd do is to re-check idle mixture, make sure primary thottle plates are closed, if engine doesn't idle enough, turn up secondary adjustment on base plate on pass side to promote good idle. Then reset idle mixture, use vacuum gauge for best vacuum reading while tuning. Should be around 12-18 inches at idle, steady reading, +/-1 inch, meaning no short lobes, stuck valves, misfiring cylinders, etc. Probably set curb idle for 900-1100 rpm
Then, one should recheck initial timing, 10-14 deg, check mechancial advance is working and vacuum advance is working correctly if used. Check the books for total amount of advance @rpm, remember, rpm given for distributer is at dist rpm, not crankshaft, just X2 the amount. Ball park figure, I would suggest is 30 -34 degrees at 3000rpm with all three advances totaled up.
Now with the above done, try again. Might try more advance till it pings, then back off two degrees on initial.
If it still bogs, disconnect the secondary side all together, it may be the mech secondary is dumping too much too fast, then you might have to try a vacuum secondary carb to correct your problem.
<HR></BLOCKQUOTE>I have the intial timing at 20 degrees and total of36 all in by 3000rpm,I use 91 octane and engine still does not ping anymore advanced and its to hard to start,I dont get any black smoke out the exhaust,so I`m thinking I need to up the nozzle size?I have the vacuum hooked to manifold vacuum.vacuum is12hg at idle and about 7hg in gear,I have a 3.5 power valve in carb.