SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: Ultra460 on January 29, 2009, 03:47:44 PM
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I have a holley 850dp and was wondering where I would go to get the choke horn milled off? Do I need to send it out to someone? Or would I be better off buying the proform main body instead?
I called my local engine machine shop and they said they don't do that and didn't have any ideas for me either.
Thanks, John
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sorry if this is a little off topic, but what is the benefit of removing the choke? I have the same carb (750 though), is there a performance gain?
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If you're skilled with a die grinder you can do it yourself. But if you're not, I would just buy a new main body that's already cut off... it would be around the same price.
As far as performance.... it might enhance the flow a bit... smoother mixture.... but it's kind of hard to test without a back to back test on the water IMO
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Most high tech carb shops will do this, but they charge more than the job is worth IMO, you want to leave about 1/8" above the air cleaner lip, not difficult with the right tools, carb obviously needs to be apart....
As far as performance, removing the choke horn is the best way to eliminate the turbulence caused by the air moving across the top of the carb. Think about a carb in a car, the carb top is inside an air filter housing and the air is virtually coming inside the carb at 360* (all the way around), now take the same carb and remove the air cleaner and the hood of the car, travel at 80 MPH, what happens? the air traveling across the top of the carb causes disturbances in the taller than the rest of the carb. choke horn, viola, there you have it, no horn, no turbulence....
GT
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Sounds good thanks for the info. I'm thinking I might just get the proform main body that's already done.
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put a straw in a cup of water, now blow accross the top of the straw at 90*see what happens. I dont know if this applies to what your doing but you need some kind of box or scoop to presurize above the carb, horn or no horn. you can always roll like me, one horn one no horn.
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I have a engine hatch and I'm not really ready to cut any holes in it yet for a scoop. That's my main reason for doing this mod. Currently I'm running a 3 1/2" tall flame arrestor so the hatch will close. That dosen't leave a whole lot of room for the air to make a clean transition into the carb
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Send it up if you decide to , will mill it cheap !
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We mill them too, and sell the main bodies and complete carbs CHEAP!!! The 950s (we checked the flow on our Superflow), we sell for $459.95!!!!! We can also set them up for your applicaion for an additional $60.00. We also boost reference blower carbs and do whatever custom work you need. We have a COMPLETE machineshop and do jet pump stock and performance mods and sell parts! P.S. I wrote the HOTBOAT pump article, and the carb article too! TIMINATOR 623-877-8553