Worldly Scions,
I'm out of ideas. I'm having problems with a ZS carb on a '78 Spitfire.
This is a stock, water heated choke, single stromberg.
The problem:
When I put the accelerator to the floor (spirited driving) after about
2 seconds, the engine bogs, I lose power & slow down. If I let up on the
accelerator
slightly, every thing is OK. I think I'm flooding it. Black exhaust smoke
comes
out under this fault condition. It happens regardless of RPM.
The car runs and starts fine under all other conditions.
The historical confusion factor:
This carb has always performed flawlessly.
I recently removed this carb (&intake together) to swap exhaust manifolds.
After re-assembly (the following day) I went for a test drive. I quickly
realized
I had forgotten to re-fit the air cleaner. I noticed it (the problem)
immediately,
but drove the car for about 5 miles. The above mentioned problem was much
worse.
I assumed at the time it must be all the turbulence around the carb intake.
It was not possible to get it above 3500 RPM.
The problem is still there with the air cleaner on now, just less severe.
RPM's not a problem,I can red-line it, I just can't get there as quickly.
What I've done:
Spray carb cleaner in it; remove carb and check; remove choke assembly
and check it. Blow compressed air thru passages; check piston damper
operation (thought this would be it for sure); switch carbs (only) with
another
car - the problem follows the carb; talk nice to it; swear at it.
I have not adjusted the carb in any way.
I'm about to replace the piston diaphram assembly (as a unit) with another
from an (unknown condition) carb on the shelf. But I don't want to introduce
any new variables.
Any suggestions welcome, email direct to me if you like.
Bob Sykes
78, 78(aaaarghh), 75 Spitfires
|