RE: TR6 Engine Problem

["Vincenti, Ross" <Ross.Vincenti@transamerica.com>]

John & Danny wrote:
   Well our 71 TR6, A.J., is almost back on the road for the first time in 
12
years.  We have one problem, though. Whenever we rev the motor and let off,
sometimes we expierence a pop back through the carbs.  We think it might be
the timing but we aren't sure.  The engine is a little lean, but we don't
think that would do this.  Any help would be greatly appreciated.
+++++++++++++++++++
I have the same problem with my Spit with twin SU HS2 carbs.  General 
consensus of the list members was that older carbs lack a compensating valve 
that would lean out the mixture when you lift off the throttle quickly, thus 
the overly rich mixture goes "boom".  I have tried fiddling with the timing 
with no success.  Finally I just got used to it and have come to like it 
actually.  I get a lot of low burbling and popping on lift throttle 
deceleration from higher revs, less so from lower revs (i.e., anything under 
3,000 rpm).  Interesting that you note the backfire coming from the carbs, 
as mine sound like they are coming strickly from the tailpipe.

Ross D. Vincenti - Costa Mesa, CA
64 Spitfire 4
64 Porsche 356C Coupe