I have two 1.75inch SU carbs on my 3.8L straight six (from a MK10) in my 150 FHC. It acts like it runs out of fuel under full throttle. Are these carbs too small for this engine? Advice?
Hmn…
The 3.8S, and Mark2 Saloons have “only” a pair of HD6 carbs feeding the 3.8, and they’re both a lot heavier than your FHC. Neither of them run out of “oompfh” at WOT, all things considered.
Have you checked that your pump is delivering enough flow?
What needles have you fitted?
yes. need to check pump output–after market 2-3psi rating. Have not check need sizes . will do . thanks for the help. Your comment on the 3.8 saloons answers my question on the HD6.
Pressure is one thing, flow another.
Fitting HD8’s would give you a bit more loud, but if your FHC is behaving like a slug, then you’ll want to rectify that first. It could be something as simple as a clogged fuel filter.
they have few miles on a rebuild with new jets/diaphrams. I my have not set things up correctly.
I use a pair of HD6s on my 420. They never feel inadequate. Until the carbs are wide open smaller carbs are an advantage.
Certainly true for regular carbs. But I thought the CD principle of SU and Stranglebergs provides more latitude for use of larger chokes, because the venturi area itself is dynamically adjusted.
thanks for the help it seems that it is clear that the HD6s are not the problem.
Update. Found two vacuum leaks. One was a LOOSE CARBURETOR! Now runs fine.