Carb size
05-30-2016, 09:04 PM
#51
Problem was the 800 carbs. One was lean, over 13:1 and the other rich at like 10.2:1. Switching carbs from one motor to the other, the problem stayed with the carbs. The are not reacting to jetting changes. Went 4 up on one 4 down on the other and they still aren't right and are 8 jet sizes apart.
I'm thinking of trying AED 950s but am now hearing people don't like the 950. Others say they will be close out of the box.....
05-30-2016, 09:06 PM
#53
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iTrader: (3)
The 311 formula would run 68 with factory 420s and ran 70 to72 with roller cam upgrades. Last Friday I was able to hit high 70s with my winter upgrades.
Problem was the 800 carbs. One was lean, over 13:1 and the other rich at like 10.2:1. Switching carbs from one motor to the other, the problem stayed with the carbs. The are not reacting to jetting changes. Went 4 up on one 4 down on the other and they still aren't right and are 8 jet sizes apart.
I'm thinking of trying AED 950s but am now hearing people don't like the 950. Others say they will be close out of the box.....
Problem was the 800 carbs. One was lean, over 13:1 and the other rich at like 10.2:1. Switching carbs from one motor to the other, the problem stayed with the carbs. The are not reacting to jetting changes. Went 4 up on one 4 down on the other and they still aren't right and are 8 jet sizes apart.
I'm thinking of trying AED 950s but am now hearing people don't like the 950. Others say they will be close out of the box.....
05-30-2016, 09:49 PM
#54
Registered
iTrader: (7)
The 311 formula would run 68 with factory 420s and ran 70 to72 with roller cam upgrades. Last Friday I was able to hit high 70s with my winter upgrades.
Problem was the 800 carbs. One was lean, over 13:1 and the other rich at like 10.2:1. Switching carbs from one motor to the other, the problem stayed with the carbs. The are not reacting to jetting changes. Went 4 up on one 4 down on the other and they still aren't right and are 8 jet sizes apart.
I'm thinking of trying AED 950s but am now hearing people don't like the 950. Others say they will be close out of the box.....
Problem was the 800 carbs. One was lean, over 13:1 and the other rich at like 10.2:1. Switching carbs from one motor to the other, the problem stayed with the carbs. The are not reacting to jetting changes. Went 4 up on one 4 down on the other and they still aren't right and are 8 jet sizes apart.
I'm thinking of trying AED 950s but am now hearing people don't like the 950. Others say they will be close out of the box.....
05-30-2016, 10:24 PM
#55
Registered
iTrader: (4)
Some good info. Make note of cfm used on average etc with the different carb sizes. It may surprise some non-carb guru's. Regardless it's good material for all of us with the exception of test engine is a stroked Ford. Lol.
http://rockettbrand.com/downloads/ar...ing%202009.pdf
http://rockettbrand.com/downloads/ar...ing%202009.pdf
Has anyone seen an HP Carb without adjustable air bleeds? The HP 950's that I have, are not adjustable, I've never seen that before.
05-31-2016, 04:13 AM
#56
Registered
iTrader: (2)
The 311 formula would run 68 with factory 420s and ran 70 to72 with roller cam upgrades. Last Friday I was able to hit high 70s with my winter upgrades.
Problem was the 800 carbs. One was lean, over 13:1 and the other rich at like 10.2:1. Switching carbs from one motor to the other, the problem stayed with the carbs. The are not reacting to jetting changes. Went 4 up on one 4 down on the other and they still aren't right and are 8 jet sizes apart.
I'm thinking of trying AED 950s but am now hearing people don't like the 950. Others say they will be close out of the box.....
Problem was the 800 carbs. One was lean, over 13:1 and the other rich at like 10.2:1. Switching carbs from one motor to the other, the problem stayed with the carbs. The are not reacting to jetting changes. Went 4 up on one 4 down on the other and they still aren't right and are 8 jet sizes apart.
I'm thinking of trying AED 950s but am now hearing people don't like the 950. Others say they will be close out of the box.....
05-31-2016, 08:36 AM
#57
05-31-2016, 09:09 AM
#59
Registered
iTrader: (3)
Something else to consider, a drag race or street carb, isnt really the same as a true marine carb. What a carb does on a dyno pull, is very close to what a drag carb is doing in its application.
Now, a marine carb, that has to operate at much larger throttle position percentage while cruising, the power valve circuitry, and so on, can make a difference.
I know i always seem like im pushing quick fuels, but i do so for a reason. Its because of what you get for the money.
Corrosion resistant diamond coating (most carbs look like crap after a while)
Billet baseplates
Billet metering blocks
Tuneable air bleeds
Tuneable power valve restrictors/jets
Tuneable idle feed restrictors
Tuneable linkage
Tuneable emulsion bleeds
Large sight glasses
Cost 650 dollars.
Thats cheaper than holleys old 850 marine carbs that have no billet parts, press in bleeds, press in idle feeds, pcvrs, and so on. I have those old 850 holleys, and while they are a good carb, ive had to drill out idle feed restrictors to get a decent idle afr, and its simply not as tuneable . Ive also ditched the stock bowls for aluminum bowls with large sight glasses, got tired of gas spilling on my painted blowers, and a bunch of other stuff. Id stil much rather work with them though, over a ****tty nickerson carb, or some of the other carbs ive seen that have been botched up. With everyone running widebands these days, it really pays to have a carb you can easily tune yourself. Changing main jets alone doesnt always get you what you want.
Now, a marine carb, that has to operate at much larger throttle position percentage while cruising, the power valve circuitry, and so on, can make a difference.
I know i always seem like im pushing quick fuels, but i do so for a reason. Its because of what you get for the money.
Corrosion resistant diamond coating (most carbs look like crap after a while)
Billet baseplates
Billet metering blocks
Tuneable air bleeds
Tuneable power valve restrictors/jets
Tuneable idle feed restrictors
Tuneable linkage
Tuneable emulsion bleeds
Large sight glasses
Cost 650 dollars.
Thats cheaper than holleys old 850 marine carbs that have no billet parts, press in bleeds, press in idle feeds, pcvrs, and so on. I have those old 850 holleys, and while they are a good carb, ive had to drill out idle feed restrictors to get a decent idle afr, and its simply not as tuneable . Ive also ditched the stock bowls for aluminum bowls with large sight glasses, got tired of gas spilling on my painted blowers, and a bunch of other stuff. Id stil much rather work with them though, over a ****tty nickerson carb, or some of the other carbs ive seen that have been botched up. With everyone running widebands these days, it really pays to have a carb you can easily tune yourself. Changing main jets alone doesnt always get you what you want.
05-31-2016, 09:31 AM
#60
Something else to consider, a drag race or street carb, isnt really the same as a true marine carb. What a carb does on a dyno pull, is very close to what a drag carb is doing in its application.
Now, a marine carb, that has to operate at much larger throttle position percentage while cruising, the power valve circuitry, and so on, can make a difference.
I know i always seem like im pushing quick fuels, but i do so for a reason. Its because of what you get for the money.
Corrosion resistant diamond coating (most carbs look like crap after a while)
Billet baseplates
Billet metering blocks
Tuneable air bleeds
Tuneable power valve restrictors/jets
Tuneable idle feed restrictors
Tuneable linkage
Tuneable emulsion bleeds
Large sight glasses
Cost 650 dollars.
Thats cheaper than holleys old 850 marine carbs that have no billet parts, press in bleeds, press in idle feeds, pcvrs, and so on. I have those old 850 holleys, and while they are a good carb, ive had to drill out idle feed restrictors to get a decent idle afr, and its simply not as tuneable . Ive also ditched the stock bowls for aluminum bowls with large sight glasses, got tired of gas spilling on my painted blowers, and a bunch of other stuff. Id stil much rather work with them though, over a ****tty nickerson carb, or some of the other carbs ive seen that have been botched up. With everyone running widebands these days, it really pays to have a carb you can easily tune yourself. Changing main jets alone doesnt always get you what you want.
Now, a marine carb, that has to operate at much larger throttle position percentage while cruising, the power valve circuitry, and so on, can make a difference.
I know i always seem like im pushing quick fuels, but i do so for a reason. Its because of what you get for the money.
Corrosion resistant diamond coating (most carbs look like crap after a while)
Billet baseplates
Billet metering blocks
Tuneable air bleeds
Tuneable power valve restrictors/jets
Tuneable idle feed restrictors
Tuneable linkage
Tuneable emulsion bleeds
Large sight glasses
Cost 650 dollars.
Thats cheaper than holleys old 850 marine carbs that have no billet parts, press in bleeds, press in idle feeds, pcvrs, and so on. I have those old 850 holleys, and while they are a good carb, ive had to drill out idle feed restrictors to get a decent idle afr, and its simply not as tuneable . Ive also ditched the stock bowls for aluminum bowls with large sight glasses, got tired of gas spilling on my painted blowers, and a bunch of other stuff. Id stil much rather work with them though, over a ****tty nickerson carb, or some of the other carbs ive seen that have been botched up. With everyone running widebands these days, it really pays to have a carb you can easily tune yourself. Changing main jets alone doesnt always get you what you want.
MILD, which Quick Fuel carb are you talking about? Looks like they all cost over 800 dollars? Would you mind posting a link? Thanks for your input
