Daytona parts Co. UN2 carburetor

[38plymouth]

Some of you may have seen my thread on my sticking throttle on the original ball and ball carburetor on my 38 plymouth. I had rebuilt that carburetor so many times over the last 25 years I don't even know and I was tired of the strip screws and gas and vacuum leaks.

 

So I did a little research online and found that Daytona parts company in New Smyrna Beach Florida sells a UN2 Universal single barrel carburetor that is supposed to be a direct Bolt on. I figured since I lived an hour away I drive up there and see the carburetor in person. I'm glad I did, I spent 45 minutes with the owner Ron and he gave me a lot of good advice on an electric fuel pump if I choose to add one and basic setup of the carburetor to make it quick and easy. I handed the man $300 cash and headed home.

 

I didn't have much time but I wanted to see if the carburetor fit. I already had the old one off because I brought it with me and I dropped the new one on and following Ron's advice I literally had the carburetor installed and the engine running and idling beautiful in 10 or 15 minutes. I hooked up my vacuum gauge and adjusted the idle mixture until I had 50 psi and the car was idling smoother than I can ever remember. I had to make a quick adjustment to the adjustable throttle on the carburetor and then the linkage bolted right up. My choke cable fit perfect and my stock air cleaner also fit perfect. I have not driven the car yet but letting it idle and revving it up in neutral it already seems to run excellent. I'll update once I get a chance to drive the car but so far I am extremely happy with this carburetor and I'm really looking forward to not dealing with that old one again. I'm going to try to attach a few pictures of side by sides with the old carb and with the new one installed.

[38plymouth]

[38plymouth]

[38plymouth]

[38plymouth]

[Sam Buchanan]

Excellent feedback! Could you share the tips you received in regard to an electric fuel pump?

[38plymouth]

I told him that I was thinking of adding an electric fuel pump to help with starting the vehicle. I generally don't drive the car all summer cuz it's too hot and when I go to start it,it turns over Forever Until it fills with fuel. He recommended not running an electric through the stock pump. He said people do it but it's generally not reliable and will almost always end up failing. He told me to put in a block off plate and just run the Electric. He also told me that he recommends ordering Carter part number p90091 from Summit racing. It's a 12 volt pump that will run on 6 volt positive ground and he said the fuel pressure is perfect for my car. He says it's a very reliable pump and it's the only one he would recommend. I believe he said it was made in the USA too.

[Sam Buchanan]

42 minutes ago, 38plymouth said:

I told him that I was thinking of adding an electric fuel pump to help with starting the vehicle. I generally don't drive the car all summer cuz it's too hot and when I go to start it,it turns over Forever Until it fills with fuel. He recommended not running an electric through the stock pump. He said people do it but it's generally not reliable and will almost always end up failing. He told me to put in a block off plate and just run the Electric. He also told me that he recommends ordering Carter part number p90091 from Summit racing. It's a 12 volt pump that will run on 6 volt positive ground and he said the fuel pressure is perfect for my car. He says it's a very reliable pump and it's the only one he would recommend. I believe he said it was made in the USA too.

 

Thanks for the info, that is interesting and parallels my experience with a full-time electric pump (and mechanical pump block-off plate) for the past five years.

 

The Carter 90091 is also available from Amazon for $20 less than the Summit price:

 

https://www.amazon.com/Carter-P90091-Electric-Fuel-Pump/dp/B07BBDSZP1

Edited August 28 by Sam Buchanan

[Sniper]

And it's $10 cheaper at RockAuto but if you throw in the shipping it's probably a wash LOL unless you're doing a RockAuto order anyway

Edited August 28 by Sniper

[38plymouth]

Just took the car for a drive and got it up to operating temperature and it ran beautiful. It accelerates better and it runs smoother. Full throttle is definitely more powerful now. I wish I bought this carburetor years ago. I would definitely recommend it if you have a worn out carburetor.

[Doug&Deb]

It’s good to know there’s another low pressure electric pump available. I’m running the Airtex E8902 currently but it’s been discontinued. I bought a cheap off brand pump for backup but I may order a Carter. I’m puzzled as to how it works with 6 volt positive ground but he wouldn’t recommend it if not.

[Sniper]

1 hour ago, Doug&Deb said:

I’m puzzled as to how it works with 6 volt positive ground

 

The motor in the pump isn't grounded to the case, so you can wire it to work with a positive or negative ground, it don't care.  Now the voltage drop will affect the output.  I went to Carter's website to look up the specs, pretty lame, imo.  No datasheet showing output vs voltage, heck they don't even tell you what pressure is expected, lol. 

 

https://carterengineered.com/electric-fuel-pump-p90091

 

[38plymouth]

I'm pretty sure the guy at Daytona Parts told me that the pump would put out three to four PSI when run on 6 volts and he said it is perfect for our carburetors.

[Sniper]

That sounds like it would be perfect and I would guess they would know.

[Ivan_B]

On 8/28/2024 at 4:11 PM, 38plymouth said:

adjusted the idle mixture until I had 50 psi

Isn't that way too high? 😮

In defense of the OEM carbs, yours appears a bit weathered. Although, if the new one comes with a bowl drain, that's definitely a plus

[38plymouth]

8 hours ago, Ivan_B said:

Isn't that way too high? 😮

In defense of the OEM carbs, yours appears a bit weathered. Although, if the new one comes with a bowl drain, that's definitely a plus

I don't really know. I adjusted the idle mixture screw to get highest vacuum which was right at 50.

[Sniper]

2 hours ago, 38plymouth said:

I don't really know. I adjusted the idle mixture screw to get highest vacuum which was right at 50.

 

I am not sure what scale you were using, but in the most commonly used on, here in the US anyway, it's inches of mercury, in/hg. just under 30 is a perfect vacuum.

 

Tell use what scale you used?

 

 

 

 

vacuum-pressure-unit-conversions-chart-from-ism.pdf

[Ivan_B]

The TS is from Florida, we use the same US scale in Florida 😅 I suspect that either the gauge is not working properly, or it has multiple units on it, and something was confused with something else.

Edited August 30 by Ivan_B

[38plymouth]

Well I indeed was looking at the gauge wrong. It was 50 cm or something what I should have reported was that it was 18 in/hg.

[Plymouthy Adams]

likely looking at the kPa scale of the gauge....slight over 15 inches of vacuum

[Sniper]

18 in/hg is kinda low, especially since you are at sea level.  A bit of tuning might be in order.  Play with the timing a bit, tweak the mixture screw a bit.  I get about 20-21 at 1600 feet above sea level.  Once you dial that in your car will really run nice.

[Sam Buchanan]

38plymouth is in Florida, with the density altitude in Florida this time of year 18" might be a pretty decent number. I'm at 592' above sea level but yesterday at mid-day the density altitude was 3800'. Tweaking to get the number as high as possible is certainly worthwhile, but that number could vary depending on local conditions.

[38plymouth]

I went out and hooked the vacuum gauge up again and made a small timing adjustment and a tiny adjustment to the idle mixture and got it up to 21". I may take it out for a drive later and make sure it doesn't detonate. I can tell it sure does idle beautiful and it's very smooth and I'm not getting all that stinky exhaust that I used to get from the old carburetor.👍

[Dave72dt]

2 hours ago, Ivan_B said:

The TS is from Florida, 

Ivan, you're the only one who has used the acronym "TS".  What, exactly does it stand for?  Maybe I'm the only one who doesn't know and if so I'll plead ignorant.  Enlighten me and maybe enlighten the world!

[Plymouthy Adams]

I am going to think the TS is     thread starter