BBF 466 Carb Size

« **on:** June 05, 2017, 06:14:42 PM »

I have a 21 Spectra cruiser, just installed a newly rebuilt 466 BBF back in it.

When i bought the boat it had a 600 cfm Holley Marine Carb on it. I upgraded to a Quick Fuel Marine 750cfm but now am being told that is too small. Couple of people have told me that the BBF in a jet boat setup likes a lot of fuel and needs an 850cfm, that i will lean it out with a 750cfm.

The original motor leaned itself on my 4th trip and burned a piston and cracked the block with the 600cfm on it. Trying to avoid that with the new motor.

The boat also has 3/8 fuel line from the tanks, through the IMCO valve/filter setup and to the pump/carb. Is that big enough as well.

I am no expert by any means, so hoping to get some feedback from the group on here. Thanks

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« **Reply #1 on:** June 05, 2017, 07:53:26 PM »

Quote from: KeoniNV on June 05, 2017, 06:14:42 PM

I have a 21 Spectra cruiser, just installed a newly rebuilt 466 BBF back in it.

When i bought the boat it had a 600 cfm Holley Marine Carb on it. I upgraded to a Quick Fuel Marine 750cfm but now am being told that is too small. Couple of people have told me that the BBF in a jet boat setup likes a lot of fuel and needs an 850cfm, that i will lean it out with a 750cfm.

The original motor leaned itself on my 4th trip and burned a piston and cracked the block with the 600cfm on it. Trying to avoid that with the new motor.

The boat also has 3/8 fuel line from the tanks, through the IMCO valve/filter setup and to the pump/carb. Is that big enough as well.

I am no expert by any means, so hoping to get some feedback from the group on here. Thanks

Sent from my iPhone using SoCal Jet Boats mobile app

I just bought a quick fuel 850 for my BBF 466. I had a Holley 750 on it before when it was stock and it ran great.
Did a lot of upgrades to the engine so It was recommended I run an 850.

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« **Reply #2 on:** June 05, 2017, 08:39:36 PM »

My bone stock original 460 still has the original 715 carb it came with.

1977 Challenger

« **Reply #3 on:** June 11, 2017, 12:12:57 PM »

Quote from: KeoniNV on June 05, 2017, 06:14:42 PM

I have a 21 Spectra cruiser, just installed a newly rebuilt 466 BBF back in it.

When i bought the boat it had a 600 cfm Holley Marine Carb on it. I upgraded to a Quick Fuel Marine 750cfm but now am being told that is too small. Couple of people have told me that the BBF in a jet boat setup likes a lot of fuel and needs an 850cfm, that i will lean it out with a 750cfm.

The boat also has 3/8 fuel line from the tanks, through the IMCO valve/filter setup and to the pump/carb. Is that big enough as well.

The 3/8-inch fuel line should be adequate for your single carb 460 assuming it's a mild engine, such as a flat tappet cammed engine.

If a carburetor such as yours is going lean at upper rpm, then jet the carburetor to correct the ;lean condition. Carb size in-and-of-itself has little to do with lean or rich, whereas carb jetting has everything to do with lean or rich. So jet accordingly.

Since you already have the 750 cfm carb, I don't think that upping to 850 cfm will make a noticeable (seat of pants) difference in your particular case.

KeoniNV

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