The Stovebolt Site Forums The Shop Area Engine Shop Rochester B -- what edition? and other Qs

If proper Carter YFs are so difficult to find, would an "improper" Carter YF be preferable to the Rochester B?

I still have the Carter YF that was on Ol' Roy when I got it. I replaced it with a rebuilt Carter YF that is correct for the truck.

The other Carter's markings indicate that it's a Frankencarb made from different Willys parts of the 1950s and 60s. When it was on the truck, it seemed to work ok.

Just my two cents, but I wanted to share some personal observations about ethanol-blended fuel and its impact on carburators over the years. I can’t back this up with scientific proof, but from my own experience, ethanol has caused me more headaches than I’d like to count.

Years ago, when ethanol was introduced into the fuel industry, I began encountering regular carburetor failures. Having a primary home in the Northeast and a secondary home in South Carolina, my yard equipment would sit unused for months at a time. During these periods, ethanol’s tendency to absorb moisture and gum up carburetors became a real pain. At its peak, I was cleaning out three or four carbs annually—often just as I needed them most! It reminds me of the present day battery failure rate with my yard tractors, wheelers, and even my jet ski; always at the worst possible times.

Back in New York before moving to my retirement home in 2013, non-ethanol fuel wasn’t available, so I was forced to deal with these issues. Now that I can access non-ethanol gas, those issues have nearly vanished. The difference has been night and day.

To cover all bases, I also mix Stabil into every tank of gas (except my daily driver) whenever I fuel up. It’s a simple step that eliminates the guesswork of tracking which equipment got treated. I use this routine across everything: my ’52 Chevy Truck, my wife’s 2007 VW Eos (which also sits for months), all the gas powered yard equipment and all of my toys.

To me, it gives me a bit more time to work on the projects I want to work on, making room for what inspires me, not just what demands my attention.

My 2 stroke equipment tends to sit for fairly long periods. I religiously use non-ethanol gas in the stuff. I’ve yet to rebuild a carb on any of it. Seems to be working.

I try very hard to run non-E in the old truck, but it’s not possible 100% of the time.

If the power piston isn't sticking (maybe due to your fuel additive...phase separation is a problem as you seem to understand), then that is a good thing. The fundamental problem is there is suction present in the power piston cylinder any time the engine is running so it will constantly suck gas up in there. And that is the problem. If GM had designed the carburetor with more than 4 screws holding it together and if they had put the power circuit outside (still controlled by vacuum but not immersed in gasoline) the carburetor in my opinion would have worked better. I even gave thought to designing such an adaptation, but the cost and the time are the problems there. In all fairness, no...it is not a good design. It makes me wonder if the person who designed it just bought the books for engineering classes and never attended. However in complete fairness, do any of us think GM thought those carburetors would still be in operation this many years later? I expect they would have been surprised to see people using them for 15 years much less 60+. So there's that. But the YF design is more effective in all ways and unless the thing just flat wears out there is really no reason that carburetor can't be used for a very long time. Jon H (CarbKing) does have some resistant diaphragms. Those will help a lot.

From the standpoint of "something more reliable and with better performance -- something I don't wanna keep screwing around with" the Carter YF is probably going to be a very good alternative. Are there better ones? Some would say the Stromberg option is good but it usually isn't cheap. And about 10 or so years ago there was a fellow here who adapted fuel injection to his 235 and claimed to have driven it something like 30,000+ miles...much more than the typical tinkering with the over the counter add-on experiments. As I recall he lived in Odessa or somewhere else in West Texas and he drove the truck all over the place. His analysis? It started easier and it ran okay but he never got it to run lean enough and it got horrible gas mileage.

There has been some discussion in this thread about alternatives to the Rochester B. Lets do a bit of discussion. The MAJOR carburetor manufacturers in the USA in the last 70 or so years would be, in alphabetic order: Autolite (a.k.a. Motorcraft), Carter, Holley, Rochester, Stromberg, and Zenith.


Autolite - the common single barrel Autolite is the 1100. I don't know enough about these to discuss their dquality / reliability, as technical data on these is as difficult to find as an honest politician; not impossible, just very difficult. I would suggest their use ONLY on OE applications for this reason.

Carter - made a number of different carburetor series: AS, BB, BBR, RBS, W, and Y. I am personally partial to most Carters because of a number of reasons: initial cost, availability of documentation, availability of parts, and quality (specifically the W and Y series). I would suggest ignoring the existence of the other 4 series. I have pitched the YF and W-1 for decades due to the above parameters.

Holley - made a number of 1 barrel carbs; common ones would be the 1904, 1908, and 1920. I do not personally care for the side-bowl design. I will not discuss these, other than to mention their existence. If others wish to chime in, be my guest.

Rochester - made the B series and the M series, as well as the side-draft R series.

Stromberg - made the A series, and the B series. It may be argued that the Stromberg was the highest quality of material and manufacture. Ignore the A series completely. There are a number of variations of the B series, all of which are good carburetors; one just needs to pick one with the internal venturi best for the application. Parts are readily available by mail order, documentation is available, costs are greater than Carter.

Zenith - made a LOT of different downdraft carburetors. The series to use would be the 28 or preferably the 228. Documentation is available, but you may have to pay for it. Parts are mostly readily available for mail order, but expensive. Quality is probably somewhere between Carter and Stromberg. Unfortunately, one can no long buy new Zenith carbs and parts from the manufacturer. All you folks buying the Chinese stuff should be proud, we lost another quality American manufacturer (and American jobs) at the end of 2025. For the ultimate single carb installation, Zenith is probably the best bet, as many different internal venturii sizes are available.

Note that I have not, nor will I discuss the modern import stuff, or the lesser known American manufacturers such as Fish.

Fuel injection - not my cup of tea; if someone else wishes to chime in, do so. I will say that my dual quad 1968 non-Chevrolet truck with 450 HP gets better fuel economy than my 1998 150 HP V-6 fuel injected non-Chevrolet truck.

Multiple carburetion - lots of pixels have been disturbed on this subject. (Opinion) If you don't already have a setup and you want a setup, look at a 3 carb manifold rather than a 2 carb manifold for the Chevrolet 6. Not saying 2 cannot be made to work. Am saying that 3 will work better.

Now, what would I use (if I had a Chevrolet 6) ?

Easy - for a single carb application I would do the math, and acquire the proper Zenith carb. But if I was not FORCED to use a single carb application, I would acquire a 3 carb intake, and run either 3 of the Carter YH sidedraft carbs (235 Corvette) or 3 Carter type W-0 carbs if I wanted downdraft (sorry Jerry).

Costs - have different meanings to different folks. I personally would rather spend more money on a quality item than more time trying to make a cheaper and inferior item work. Again, my opinion only. How much is your time worth ?

Jon

So, after using Jon's tech tips as well as home-baking some internal components, I reassembled the Rochester B and will reinstall it on the truck when some free time comes along.
Too bad it can't be fully bench-tested before mounting it.

Fyi, I found some gasket prep to help with sealing the assembly (hand-cut 1/32" Karropak for the gaskets).

The semi-liquid is Permatex -- Permashield, and is advertised as resealable, heat resistant and fully ethanol compatible!
But my gosh was it difficult to source here in Canada -- only Lordco stocks a very limited supply.

I'll get back to you all with my carb results...

Took advantage of some dry mild winter weather and installed the carb onto the truck. After some cranking the thing started and idled ok. Took it out for a spin and it has regained its power.

One little niggle though ...there is a perceptible lag/bog between rapid acceleration (pump) and power circuit. I can live with that as long as it doesn't worsen.

The rebuild of the leather cup and newly fashioned return spring (accel pump), Jon's tech tips for dewarping and improving vacuum transfer between carb bodies, and cutting new gaskets (with Permashield) seemed to have been a big improvement on this old tech.

The next startup (after sitting for several weeks) will tell a bit more of the story, I guess. If it fails, then a new carb it will be!

Next up are the valve adjustments and recheck the ignition circuits -- there is a tiny bit of a rough high-idle and a bit of engine pinging on hard-driving in 4th gear.

Your timing is probably too far advanced if you're getting pinging. Set it to the BB on the flywheel per the manual.

Dun dat, but had to advance it from there to get it run with any power (long prior to the carb rebuilding).

Methinks it's to do with running ethanol. Will retard it a touch and see if that helps.

Ethanol wouldn't contribute to knocking or pinging. Pure ethanol has an octane rating of 114. It's used as an additive in regular gasoline to raise the octane level.

My truck has run on nothing but ethanol E-10 since it was awakened from its Rip Van Winkle slumber 5 years ago. I've put 10-12 thousand miles on it in that time without any knocking or pinging. I regularly drive on the freeway at 55-65 with no lack of power. The engine has not been rebuilt.

Check your ignition system for a weak spark or any other issues.

You should also get one of Jon G's 200,000 hr condensers to insure a consistent spark. The condensers available today from any parts store are Chinese garbage that don't work properly.

https://www.stovebolt.com/ubbthread...oved-condenser-annual-update#Post1595503

Thanks for your thoughts, Otto.

Yes, I plan to look into the ignition ...again.

I also have a store of NOS distributor parts (points, rotors, caps, condensers) from eons ago.

Unfortunately, Jon's condenser/cap will be too darn pricey by the time it lands in Canada here.

I'm also toying with the idea of solid state retrofit (ie, Petronix) for the distributor.
That theme was popular even back in the 60s'!

But first, I wanna exclude the usual suspects.

Disagree!
I'm in Canada, close to you and I bought one of Jon's condensers. It was not pricey; cost including shipping via USPS was very reasonable. It was delivered right to my mailbox without any additional charges/fees.

Thanks ..I may give it a try. So what was your C$ landed door cost?

Cost was $24.50 plus $3.10 PayPal fee - USD. This was 18 months ago. I think Jon was forced to raise his price a few months ago. There is a "condenser update" thread that you can read.

Thanks, Gord

Probably closer to $C40 these days -- now that becomes an expensive capacitor/condenser.

Up until 6 months ago I was ordering truck stuff from the US, but the landing costs started killing my budget.

Heck, like everything else in fixing this truck lately, I may just grab an appropriate (ceramic/film) cap from my stuff and ground it within a used condenser shell.
.22 uf 600+ v ought to do it, huh

I’m not convinced the power valve is operating properly which could account for the bog you’re experiencing.

After looking at the operation details, I cannot disagree with you.

I did polish the piston and bore, and lubed with silicone grease. It slipped quite well. But did bind if not absolutely perpendicular in the bore.

Don't wanna yank this rebuild apart again and disturb the gasket seal.

However, there's the spare (Autoline rebuild) carb that I also rebuilt at the same time. And I may just swap them if this current operating one gives me big issues.

But so far it's quite workable ...just not perfect, and reminiscent of the "before times"