Technical rochester questions

Hey Guys.
My chevy 216" is running with 2 rochester carbs. it runs ok. But during acceleration, it blasts a little, as if it gets too much fuel. Once it is up to speed it runs perfectly. Do any of you know how to adjust these rochester? I've never messed with rochester before. What about the ignition, where do you set that at?
Thank you in advance. Andreas from Denmark
(Sorry for my bad American. school just wasn´t me )

 

Yesterday I was just in the workshop, and had looked a little more on my chevy. When it is idling and I give it quick throttle so syringes gasoline up the rear carburator. Could it possibly be something with acceleration pump? I also have problems with my wipers. Is it wrong that the vacuum hose is connected to the intake? Look at the picture.

 

To start off with it not running work the linkage and see if the accelerator pump is squirting gas in both carbs.

 

Perhaps a Vacuum leak? By the way, isn't the carb insulator suppose to be installed between the carb and and the intake?

 

There is no vacuum leak. Sorry but i dont know what a "carb insulator" is. Maybe its just because i dont understand it. Im not that good at American.

Andreas (From Denmark)

 

I am not sure what you are seeing that I am not.

 

Hey

Carb insulator is a piece of plastic to put between carb or manifold.

Det er lige som det plastik der sidder under karburatoren på en Volvo B20, så benzinen ikke koger i karburatoren.

Where are you from in Denmark?

 

If you have any doubts about the wiper motor just plug the vacuum line till you get the carbs figured out. I ***ume it idles well since you only mentioned the problem on acceleration.

 

Here's a pic of the insulator and wrong gasket. Notice how the vacuum ports would be blocked if used together.
Don't think that is your problem if it idles well.

 

Thank you volvobrynk, now i get it I dont think thats the problem, because it is also doing it when it is cold.

 

Most welcome, any one who asked for help, deserves to get it!

What is the issues with the wipers? Do they stop when going up hill or under acceleration
Tell all the symthoms!

 

54fierro, thank you. It idles very well. But when i try to rev it up fast, its blowing the fuel of the top of the rear carburetor, and it is drowning.

 

Are both carbs the same size ?
Are they both jetted the same?
Have you balanced them like with a uni sync ?

 

I have not had them separated, so I do not know about the jets. Where can I buy parts for such a Rochester? Do you know approximately how big a jet you have to ***ume? I have to find a unisync and balance them the right way.

 

It is my plan to get me one like this, is it not fine enough to synchronize them with?

 

You can also use a Vacuum gauge. There's a thread on here about that or you can search the web.

 

When you open the throttle fast (both carbs) fuel sprays out of the top of the rear carb?

This should not happen - fuel from the accelerator pump should spray DOWN into the carb, not up.
Try it with the engine not running, look inside, compare with front carb

 

i will try with the engine not running. thak you

 

It sounds to me like, he has a sub-floater or a needle valve that dosen't work proberly.

At least as long as when he explains it to me in Danish.

He explains it like it bogs under load, an then I pulls like it's surpose to and the it squints out of the carb. I Think it goes out thru the floater chamber over flow.
But I think he should pull them apart, and check EVERTHING and then start over.
Plug of the wipers and deal with them afterwards.

But I'm gonna talk to him later over the phone. After work

 

Hello guys. So I have been in the workshop and work on the car. After I separated the carb apart, I found out they were not all alike inside. But a buddy had one, so I could make two alike. And now it is still fine at idle and gas takes fine. But when I have to drive the car, it blasts a lot up through the gears. I tried changing the ignition (but no fire pistol) by ear. It changed nothing. So I took the spark plugs out and cleaned (they were very black) it is still the same. I should of course have a fire pistol on when I adjust the ignition and a vacuum gauge when I adjust carburetors. But a basic setting should also be able to run without blasting. How do I find out if the vacuum performance of the ignition works okay??? A buddy said that it could also be the cam which was worn, but I dont know? Hope you have some ideas. Thanks in advance. Andreas from Denmark.

 

If you think it is too rick you could solder the jets closed and redrill with a smaller drill bit.

 

Sounds rich and you already beat me to it by pulling the plugs and seeing what they look like. I'd suggest to start with jetting it down (same jets in both carbs) and get your plugs right and go from there. The fact that it runs up okay to me says more carb issue than igntion.

I had a similiar problem in my 6 (3x1 setup) and chased ignition and timing only to come back to jets. As far as where to buy jets I've purchased several from here on line with fast shipping and no issues.

http://quadrajetparts.com/rochester-1bbl-parts-c-241.html?osCsid=0d2fac3f9a5ce8eca6260ca5aa0e1bd2

Good luck and good looking set up you have there.

 

Thank you guys. I will try look at the jets again. Which sparkplugs would you go with?

"Ricks Garage" sorry but i`m not sure what you mean. Please try to write it in a different way?

 

I'd go with some AC-R45's as a starting point. But like engine oil each have their own preference for brand.

 

One other thing...I had those same air cleaners on my sbc 3x2 setup and I won't bore you with the details but learned they can be restrictive to air flow which could be part of your rich condition too. They look good but I went to an open element design..... for what it's worth.

 

In fact, I thought well of it when I messed with the carburetor, without air filters, it went better than when I put them on. It was as if the air screws did not react with the filters on. That was a good hint. Thank you.

 

Talking about oil. What engine oil, and what transmission oil would you go for? and where do they sell the air filters with a better "airflow"???

 

Well there's enough on here about engine oil so I won't hi-jack your thread with getting into that but I will suggest make sure you have a product with zinc in it or run an additive. Search ZDDP, grab a beer and start reading. Transmission oil ***uming it still has the stock 3 speed in it - any quality 90w would be fine.
I switched to air cleaners from O'Brien Truckers (alliance vendor)....insided is a K&N element.

 

Thank you very much. Which car has the honor of running with the lovely engine ???

 

It's in a chevy roadster. Good luck and keep us posted of what you figure out.