The Stovebolt Site Forums The Shop Area Engine Shop Is it worth it yo buy a rebuilt Rochester B carb?

Looking for some advice from those who have been down this road before. Just rebuilt my Rochester carb - and its still not right. Was my first crab rebuild but it seemed pretty straightforward. Put it back in - wouldn't start without starting fluid. Then when I got it started - it would only run for about a minute before dying. Without being a crab expert - thinking about buying a carb rebuilt by a pro. Any body had a good experience with pro rebuilt Rochester B?

If you cleaned all the ports and replaced the jets and gaskets, could be the float setting is off and not enough gas in the bowl. Could also be a bad accelerator pump. Did you have an instruction sheet with your rebuild kit?
Harold

Sounds like what Harold is saying is right-on. Check your float LEVEL,and DROP. Level should be 1-9/32. Can't remember exactly what the drop level spec. is. That was my problem. After adjusting for the third time,I finally got it (level), right,(2nd carburetor). Did you soak the accelerator pump leather with oil,prior to installation,to expand the leather? Did you check your vacuum,(with gauge),as you adjusted your fuel/air mixture? That makes a BIG difference, as well. If neither one of those remedies the problem,check for vacuum leaks around the carburetor halves,(Mine was warped,so I found another one,and rebuilt it),the base of the carb,and the base of the intake. Hope this helps.

I rebuilt mine and missed the power piston circuit. I just assumed there were no moving parts. After it wouldn't run right I went back and did my homework,read up on it abit. It seems my power piston was frozen in the bore.Pretty common problem I hear.So I freed it up and all was good.I also had a small issue with a missing hole in a new bowl gasket.
Rebuilding a carb isn't brain surgery but they are fairly complex and well thought out units.Even the simple rochester B.If you don't know how your carb works it's easy to miss stuff when rebuilding.Also once you understand the mechanics of it it's easier to diagnose problems down the road.
I've only rebuilt some 10 to 20 carbs over the years. From holley four barrels to rochesters with electronic gizmos sticking out of them to those throttle body fuel injector things. I was delighted to work on my little rochester B. It is nice carburetor. Very simple and efficient.---Jack

I have rebuilt a lot of carbs. I like doing it. The only time I've ever had an issue after rebuilding a carb was when I rebuilt my Rochester B. In fact I built two in a row and neither one runs "right". Don't get me wrong, after the rebuild the truck runs a LOT better, I can brake traction with these big old 30 inch 10 ply tires and the old 216, but I'm always tweeking it a bit to keep it running decent.

That said, I would never pay for a Rochester B, rebuilt or otherwise. I've got eight of them now and every one of them was free. If I'm going to pay for a carb, I'm going to pay for a Carter (as soon as I'm educated enough to know which one to get).

Now that I think of it, you might want to turn your idle mixture screw out a couple more turns and see if that makes a difference. After I rebuilt both my Rochesters neither one wanted to start with the screw turned out one and a half turns, and when it did I could hardly keep it running.

Just a comment on the comments: You won't find new jets in the usual Rochester B rebuild kit and that shouldn't be a problem. They are a pretty simple carburetor and they work well when done correctly.

You need to see if there is fuel going into the throat when throttle is cycled. Using starting fluid seems to indicate no fuel squirting. Which is why the others have said accel pump and float level. First see if you have fuel entering the throat. It might be a dribble. Need good flashlight. There are entire Youtubes on rebuilding a B1. If it ran fairly good before, then it's something you did or did not do. Stay with it, it's your first build. Start over, look at the videos. Check the parts list for every little part, ball, correct gasket and correct gasket orientation, oil the accel pump leather and be sure all parts are there and not on the floor. Make sure all holes in intake manifold are either plugged or used.

Ok gents, thank you for your comments. Gotta love this site. Collectively you have given me a number of things to go back & check. Think I'll try it again. One Q: how exactly do I check the vacuum on the carb? Haven't done that before.

Shank

Rent, buy, or borrow a vacuum gauge (I got one cheap from Napa). Remove the vacuum hose from the port on the side of the intake manifold that runs to the vacuum wiper. Fit the hose from your vacuum gauge to that port(nipple, what ever). When you adjust the idle mixture screw and the curb idle screw, you want to adjust for the highest vacuum reading while maintaining a good (and smooth) engine idle speed.

http://www.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html

Adjust the carburetor mixture to achieve maximum vacuum reading (at idle speed).

Adjust the timing to achieve maximum vacuum (at idle speed).

These settings are about as good as you need on a 216/235/261.

There is no quicker and easier way to adjust the mixture and the timing.

Perfect - thanks