Problem solved!
Sent the fuel pump out and had all seals replaced and recal. on bench for $270.00 plus over night freight. Installed it back in the plane and made minor adjustments. At first solved mixture problem and was able to lean to proper fuel flow. However, once in cruise setting of 2450 RPM and 30 inches of MP, when I advanced the throttle to 32 inches MP, engine would die than return rapidly until I reset throttle back to 30 inches on MP. Advancing the mixture to rich did not help nor low pressure boost pump. Drove me crazy for a couple of days. This evening, took the flow divided apart and cleaned it with air pressure and made sure the check valve was operating. Put it back in plane and ran the engine....problem solved. Must have been a speck of dirt under the check valve that was to small to see with the eye.
Thanks for suggestions.
Cheers
Jerry
