View single post by Mark Rosenbaum
 Posted: 10-03-2005 04:23 pm
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Mark Rosenbaum

Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
Congratulations on your success in dealing with a particularly difficult set of problems.

I'm curious about your 'new and improved' crank pulley.  What is the 'gauge' you're using with it?  How certain are you that the 'scratch' mark on the pulley actually represents TDC for the #1 (front) cylinder?  If this mark does not accurately indicate TDC, your timing issues may disappear once you correct the situation.

Improper cam timing can also cause all sorts of performance issues.  Once you know for certain where #1 TDC actually is, verify that your cam timing is correct (i.e. the index marks on the two cam gears should align when the #1 piston is at TDC for the start of its power stroke).  If a PO made an error here you'll need to correct it.  But don't guess about TDC as there's a serious risk of valves hitting pistons and bending, if you get the cam timing too far off.

Your low-speed performance issues sound like carb problems in addition to whatever ignition and/or cam timing problems you may still have.  The cloud of fuel mist you describe is normal if it occurs when the throttle closes after one revs up the engine -- it's an 'echo' that results when high-speed gas flow is reflected back from the closed throttle and passes out the carburetor throat into the atmosphere.  This phenomenon occurs in all engines but happens to be particularly visible with Strombergs.  Having it appear at only one carburetor suggests that there's something out of sorts with the other carburetor.