ToddMcF2002
Well-Known Member
Hi 440 with a Quick Fuel 750 (vacuum secondary) that is backfiring out of my secondary if I stab the throttle fast. Always visible flames, and I had one large fireball that pretty entertaining. If I rev up slow no problems. I think my secondaries are going lean. I have make a couple changes at once that is worth noting:
- New MSD 6AL
- I recurved the MSD billet distributor with light silver, light blue, black bushing.
- Timing set at 20 initial (a bit high for a 440 with a mild/stock cam???) (need to check all in advance)
- switched to a cast iron stock intake
- new MSD cap, rotor, Autolite 85's and MSD wires. Checked firing order multiple times (check order again! Check for timing light activity on all new wires)
- exhaust smells, burns eyes. I thought it was rich but I'm hearing that indicates lean? I can't learn much from the old plugs because I fouled them all last week with fuel diagnosing the bad MSD
- no notable play in accelerator pump
- need to check for any vacuum leaks (need to check with brake cleaner)
- I have NOT adjusted the secondary open rate (Quick Fuel has an adjustment screw)
- poorly seating intake valve? need to check compression
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I've bolded what I plan to look into. Any ideas on anything else I should look at?
- New MSD 6AL
- I recurved the MSD billet distributor with light silver, light blue, black bushing.
- Timing set at 20 initial (a bit high for a 440 with a mild/stock cam???) (need to check all in advance)
- switched to a cast iron stock intake
- new MSD cap, rotor, Autolite 85's and MSD wires. Checked firing order multiple times (check order again! Check for timing light activity on all new wires)
- exhaust smells, burns eyes. I thought it was rich but I'm hearing that indicates lean? I can't learn much from the old plugs because I fouled them all last week with fuel diagnosing the bad MSD
- no notable play in accelerator pump
- need to check for any vacuum leaks (need to check with brake cleaner)
- I have NOT adjusted the secondary open rate (Quick Fuel has an adjustment screw)
- poorly seating intake valve? need to check compression
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I've bolded what I plan to look into. Any ideas on anything else I should look at?