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07-04-2018, 11:42 AM | #1 |
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Join Date: May 2013
Location: Seal beach,CA
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Carb riser on stromberg 81 carb
Happy 4th to all barners,
I have a question about the downdraft carbs using the carb risers 4”;6” and 8”. What significant benefit does this have installing a 2-carb set up on a model a engine. Thank you, Jim m |
07-04-2018, 07:38 PM | #3 |
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Join Date: May 2013
Location: Seal beach,CA
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Re: Carb riser on stromberg 81 carb
Frank,
Very good article explains the process and answers that question! Thank you, Jim m |
07-05-2018, 09:14 AM | #4 |
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Location: Charlotte, NC
Posts: 310
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Re: Carb riser on stromberg 81 carb
I'm fighting the problem (never run a downdraft before) with a Stromberg 97 on a Model A which is inserted with a Lions head. Runs good except for start up. It is flooded without any choke...has to burn off gas...bothers me as I don't want to wash the rings out. Only time it doesn't blubber is when I have just driven it? I'm wondering if the fuel pump pressure is too high? I've got a "Burns" setup with two Stromberg 81's but feel I don't need two carbs so am not going to use it. Any help on the fuel at start up...?
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07-05-2018, 10:06 AM | #5 |
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Location: new britain,ct 06052
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Re: Carb riser on stromberg 81 carb
Try swapping one of the 81's for the 97 or have "Uncle Max" on the EV* forum rebuild the 97.
Paul in CT |
07-05-2018, 10:49 AM | #6 |
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Re: Carb riser on stromberg 81 carb
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07-05-2018, 11:56 AM | #7 |
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Re: Carb riser on stromberg 81 carb
Mr. Bruce, I would shut your fuel pump off 30 seconds, or more, before turning off the engine. This eliminates any pressure in the system. Residual line pressure will push fuel into the bowl as the engine sits there, and cause your starting problem. I shut mine off as I enter my driveway. You might also check the fuel level in the bowls to be sure they aren't too high. A pair of 81's isn't too much in most cases but I recommend one 97 for a mild touring engine. I run three 81's on my speedster, it runs great and gets good fuel mileage.
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07-05-2018, 11:59 AM | #8 |
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Re: Carb riser on stromberg 81 carb
emf, Not sure that I agree with the article on spacers. I believe longer 'runners' give more velocity, so run better on the street. Try them on your A and see how they work.
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07-05-2018, 12:36 PM | #9 | |
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Location: Charlotte, NC
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Re: Carb riser on stromberg 81 carb
Quote:
That's the info I was looking for, I was shutting my tank off coming down the road but I don't think the shut off is that good so I had bought a switch and was going to do what you said. So, you confirmed what I was thinking...thank you...not used to these down draft carbs. Love the looks of them. |
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07-05-2018, 01:33 PM | #10 |
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Location: Hudson, NY
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Re: Carb riser on stromberg 81 carb
Jim, I was just pointing to an article that talked about risers. My pair of 81's on a Burns manifold run just fine for me without risers.
Frank |
07-05-2018, 10:50 PM | #11 |
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Join Date: Jan 2015
Location: New York
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Re: Carb riser on stromberg 81 carb
I have a 97 on mine, I just disconnected the fuel pump and regulator, I was getting similar problems. I do prefer to run gravity feed because its 2 less items I need to worry about. The only problem is, I cant go over 60mph on gravity.
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07-05-2018, 10:52 PM | #12 |
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Join Date: May 2013
Location: Seal beach,CA
Posts: 68
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Re: Carb riser on stromberg 81 carb
I’m going to first try running gravity feed, see how that works out. Keeping the 81’s as low as possible without any phenolic spacers. Spoke to Charlie Price(Vintage Speed-Florida) he mentions keeping the carbs low and use 2nd carb with just a slight crack opening!
Jim m |
07-06-2018, 11:44 AM | #13 |
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Re: Carb riser on stromberg 81 carb
emf, I don't run risers either, and have good luck with them. I do some racing, and have seen a lot of articles on this, so just repeating what I have seen, and believe.
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07-07-2018, 10:50 AM | #14 | |
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Re: Carb riser on stromberg 81 carb
Quote:
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