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Newbie with Carb questions...

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rjfoster03

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Recently purchased a 66' Sprite and have a few questions.

In the process of changing all fluids, tune-up, etc... When I pulled the plugs they are sooty black. I know that the prior owner used the choke more than I would think it should be used when driving. I am assuming that it is running rich due to the coloration of the plugs.

The car does "gurgle" / backfire upon downshifting / slowing down.

I am thinking that the carb needs to be tuned and if like my motorcycles, re-jetting is in order.

Am I correct on this?

If so, I need to know what is the best way to handle the re-jetting. I have done this on a honda motorcycle, but the carb is a little different.

From what I see on the carb:
InterC
Serial # 009541
DGV 5A
32 36

1. Can anyone tell me about the carb that I have?
2. Is this best to have someone "qualified" to do this if I am mechanically able?
3. Best way to select proper size jets?

Thanks for any help.
 
I would do a YouTube search for University Motors and there you will find a video by John Twist showing you exactly how tune your dual SU Carbs. Re-jetting these is really replacing the jets where the needle moves in and out. Simple job to replace. Contact Joe Curto in NY for parts. The biggie to check is the clearance for the throat plate shaft where it turns in the carb body. You may have a tough time adjusting the carbs if there is significant wear on the brass shaft.Hope this helps.
 
You have a 32/36 DGV Weber downdraft carb.
This is a 2 stage progressive system.
Jetting is an issue for these carbs, and there are some very knowledgeable people here who should be able to help you with this particular application.

BTW - welcome to the forum! A 66 Sprite is a nice Mark 3 (early car), got any pictures?
 
Welcome! Rick has it right and I imagine there are folks that can get it right but in my opinion you would be happier with the stock dual SU set up. Probably find one on e-bay if it did'nt come with the car. I had a midget with that setup and it came with a coffee can full of jets, venturis and what have you. Former owner had been fooling with it for quite a while and though it ran fine it barely beat 20 MPG and smoked black. I sold the car without fooling with it.
 
Ask Kim (regularman) - he has a Midget with a Weber and gets great mileage and power. His Weber sounds like it's pretty well dialed in.

That said, I also prefer a good set of SU's. The HS2 is well suited to these little motors.
 
When I got my '63 it had a Weber 32/36 but the original twin SU carbs were in boxes. I wasn't real happy with Weber, it needs time and understanding to get set up well and even then I'm told it really isn't any better then the SUs. I cleaned up the SUs put 'em on and sold the Weber and manifold on ebay. No regrets.
 
If you don't know much about the Webers, I think you'll find a set of SUs a lot easier to deal with. I've been tweaking SUs since I was 16 (reverse those digits and you'll be close to my current age!) and I find the idea of Weber DGVs a little intimidating. There are a bunch of places that will rebuild a set of SUs for you and get them working really well. Not hard to do yourself, either, but I got the feeling that you weren't really up for it.
 
Agreed, I was floored by the simplicity (and elegance) of the SUs compared to a Weber. I managed to get mine to a place where they were better then the Weber and I'd never touched an SU before in my life (and only a handful of carbs of any type for that matter). Of course, I already had a pretty decent set of SUs with manifold in hand so I didn't have to spend a dime to try my hand at it. Would be different if I had to spend $$$ just to experiment.
 
Wanted to thank everyone for the information.

I work at a community college and the automotive department is needing cars to look at brakes and I have an appt set up for them to take a look..... The department chair started his carer on British cars and he is excited to have the car being brought in. I have already told him I have several questions for him. Not sure as to posting pictures, but guess attachments are the easiest to do.

Thanks again.
 

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I just went through lousy experience with my Weber carb. I found a set of HS2s on Craigslist and had BillM work on them. Swapped out the Weber for the SUs and the car finally runs. I would take the counseling of the Forum and get rid of the Weber for SUs. I don't know anything about the SU carbs, but with the Forum and friends like BillM, I'm pretty confident I'll learn all there is to know.
 
lbc_newbie said:
I just went through lousy experience with my Weber carb. I found a set of HS2s on Craigslist and had BillM work on them. Swapped out the Weber for the SUs and the car finally runs. I would take the counseling of the Forum and get rid of the Weber for SUs. I don't know anything about the SU carbs, but with the Forum and friends like BillM, I'm pretty confident I'll learn all there is to know.
Click to expand...


ditto, If I had it to do all over again I wouldn't have replaced my Weber DGV with another. I wanted the car back running again quickly, so I stayed on the same path. I'm torm b/w SU's and MS. Su's would be a quicker solution, but I like the idea of laptop tuning and my car running exacly how I want it to in seconds.

car runs o.k for now, I'm having a few problem with fuel, but I believe it to be with my crappy aftermarket electric pump and possible vaporlock. I can't fully blame it on the carb, but I'm still not happy with it.

I'll probably have enough time to build my system before I have to do anything.

SU's are VERY similar to the carbs on your old Honda, so ther will be no suprises there.

I've often toyed with the idea of swapping a set of Minkuni's over to a LBC, but haven't founde a cheap set yet and threw away all of my parts from when I was a Honda mc tech.

Here's a few Weber tuning links:

https://www.dimequarterly.tierranet.com/articles/tech_weber_tuning.html

https://www.redlineweber.com/html/Tech/Table_of_contents.htm

Like lbc said, lots of friendly folks here that can walk you through SU's and probably have everything you need. Plus, SU's just look right.
 
I'm going to also report that I had a 32/36 DGV on my Midget. It had a flat spot at the low in as big as Pittsburgh...it was awful. Fiddled and tuned and even rejetted for a couple of months, then gave up and went back to the SUs and sold the Weber.
 
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