Carter YH Carbs?

8122pbrainard wrote: The trick is NOT following the float level setting per the instructions. The instructions are written for automotive when the carbs are level. Lower the aft level. The forward may need to be raised.

Yes, I have the Interceptor manual with the 'marine' float settings which were carefully followed....

Forget originality and get rid of the carters is the most efficient way of eliminating the problem. Want to satisfy the original mongers you can simply block off the rear carb port on the manifold and run with one. If I read your past post on researching them correctly the cfm remains similar. I did read a post in the past there one of the Meloons had done this. Personally I have had my share of boat fires from these carbs and am done with them for life. Want some I have three complete assemblies. Also have a couple AMC 327 engines for sale.

OLD THREAD REVIVAL:

I surrender. I've rebuilt my YH carbs twice, and sent them out to a recommended rebuild service, all to no avail. Still have fuel flowing out the aft carb choke horn.
Has anyone found someone who can actually get these carbs to work properly without being a fire hazard?
I don't want to rile the Brainard overlord or originality, but if I must... thx

63CCSN wrote: Hi all! I'm looking for rebuilt Carter Sidedraft Carbs for my 312 Interceptor. Anyone know of a source for them? I believe they are YH's. Thanks!

Try Here

Okay, here we go – This reply will be really messy and disconnected (sorry) but has some good info. on the YH carbs and a possible CFM number we were discussing above:

Carb Doctor web site's email = doc@carburetor.ca <doc@carburetor.ca>
I e-mailed this guy with the question: How many CFM for the Carter YH?
Hopefully he'll pass some info. back my way.
Carb Doc Phone # : 780-968-6622

Nice diagram with lots of data from a 1952 to 1955 Nash car (Ambassador) that used YH carbs at this site:
http://oldcarmanualproject.com/manuals/Carbs/Carter/Nash/pages/p_%2040_jpg.htm

Old Corvette web site – 6 cyl. Used the YH Carter carb:
http://www.carburetor.ca/pdf_manuals/Carter/YHmanuals1.pdf
or:
http://www.tocmp.com/manuals/Carbs/Carter/YH/index.htm
(same thing – "non pdf" – i.e. just click on a page to view)

Corvairs used them too...

Here's a site (Black Hawk Engineering) that seems to indicate that the YH's original CFM was 128 (CFM) if I'm reading correctly:   
http://www.blackhawkengr.com/
Quote from site:
"The throttle body has a 1.83" bore to fit the F flow (180 HP) turbocharger inlet bore. The Performance Trends "Engine Analyzer" simulation software predicts that the throttle body will flow 256 CFM versus 128 CFM for the original "180 HP" YH carburetor. With the boost limited to 12 PSI for longevity, Engine Analyzer predicts 193 HP net versus the 148 net HP of the stock "180 HP" system. The EFI system is able to produce better fuel economy despite generating more power. I will also manufacture smaller throttle bodies for the B-flow (150 HP) turbochargers."

If 128CFM is correct, I guess that means "two" would do only 256CFM?

Another link to the same info. (same site). It's a fuel injection throttle body for turbosharged Corvairs that also used the YH carbs (Wow! Pretty interesting stuff!):   
http://www.blackhawkengr.com/Black%20Hawk%20Engineering%20-%20Bolt%20On%20Turbo%20Fuel%20Injection.htm

Ooo! Another site that says 128CFM --- "4 each Carter YH (sidedraft) carbs from a 6-cylinder Corvette bolt to the triangular flanges.......I think that Turbo Corvairs and some Nashes also used these carbs. I wonder how well it ran with that setup? You'd think it would be better with a divider in the runners...?The carbs I think are 128 CFM each X 4 = 512 CFM. You are right, sounds kind of undercarbed for a 331. At 4800 RPM it should use 542 CFM (if my math is right)."
Site Link:http://caddy500.com/index.php?topic=336.25;wap2

And here's a cool site that shows what CFM you should have based on the c.i. vs the max RPM's expected (recommended):
http://www.buicks.net/shop/reference/carb_cfm.htm
This stie also has a nifty "enter your RPM's and C.I.'s and get your needed CFM for a carb" chart!
Or an equation to do it by hand.

And another similar site: http://slitherclothing.wordpress.com/2007/06/29/how-to-calculate-correct-carb-size/

In each case, it looks like, if you use the 312 Interceptor as an example, it yields a CFM a good bit higher than what 128CFM x 2 would be (256CFM), assuming the two sites referenced above are right about only 128 CFM for the Carter YH side drafts.

Man, this is almost as much fun as playing with Propeller Calculators, but I'm whipped from staring at the computer screen to long! I think my eye sockets are gonna need some PB Blaster soon if I don't stop now!

I saw an old ratty Atom Skier with one of those a few years ago in Freeport, ME.

I like Reid's. It looks like it's off of an old TBird.

Pete, Reid's is too subtle, we're going with one of these.

Pete's going to hammer you.

Riley,

Any chance you have a pic of the engine from the front?
I changed the intake to accept a Holley and need to see how it's plumbed.

Thanks

Pete - Hope you can find it (the Carter's cfm). It seemed to me like we were thinking that the 2 together would equal around 500 cfm?
On the break-in (you guys were discussing), again, "it seems to me" like when I put the PCM 351 in my Cobalt, they recommended running it for a minimum of twenty minutes at no more that (I think) 2500 RPM's (or thereabouts) and then little spurts maybe of a bit more and a bit less, but not Wide Open at first (forget how long -- I know this is a great help ins't it)?
It's been 9 years ago now and I've only ever done an install once, but that's what I seem to remember.
What I remember "most clearly" about "break in day" was that there was this stupid Bayliner pulling along side me looking like he wanted to race a little and I couldn't (wouldn't) go any faster until it was broke in! I figured my boat was quite a bit faster (does mid 50's and with older engine did high 50's), but I couldn't punch the throttle yet at that point!
Later found out that that particular Bayliner was actually pretty quick. It would run in the mid fifties, which I don't think most Bayliners could do in the approx. 1999 time period. I think it had a 350 Chevy.

I don't seem to have that page. What's the red line on the 6? An auto site said 4400, but that seems high.

So it sounds like my coil is in a ok place, where it's supposed to be?

We don't have a tach. SW makes a nice repro that will match the gauges that I'm planning on buying. I'll use a tach and dwell when I set the initial timing. Manual says idle should be 700 rpm. I suppose if I set at 6 BTDC at 700 I ought to be close enough. I then think I will use the break in schedule in the later Interceptor manual which is the babying method. Does that sound right to you?

8122pbrainard wrote: Bruce, The 6's and 8's show the same in my manual. My 312 red lines right about where the book shows which is 4200 - 4300. Go according the marine specs on the timing. The marine version may be cammed for more torque (many marines were) and that may be the difference in the timing spec. It's been so long since I did a tune up (you know the 28 year old points that are still going strong!!!) that I had a hard time remembering about the timing!! The marks are on the flywheel on the 312. There is a "inspection" cover on the top of the bellhousing that needs to be removed. Look for one on your 6. Edit: I forgot your flywheel forward. Did you paint over the mark on the flywheel? There should be a grove cut in it someplace. Edit again: I just looked at you picture of the painted engine. Looks like there's a pointer sticking out of the shroud around the flywheel right about on the top. Is it?

Pete, I'll have to check out the 6 later this weekend. I'm not too concerned right now about that one because PO said the engine ran good and the points, even the gap look fine.

The 312 on the other hand has been rebuilt and only run for a few minutes. It has to be timed. I don't want to do the initial timing at 2600 rpm. There is an inspection plate on the bell housing, but it looks like the coil was put in a poor place.


I haven't found any rpm specs in that manual.

Here's sort of an answer to my own question about a four barrel on the 312.

This link is to a site discussing a double four barrel on a 312, but the first sentence in the short article talks about adding a 4 bbl to a 312 and getting 235hp.
http://www.ctci.org/membership/Gilsgarage/19568VOption.htm

Intersting.

Bruce,
The 6's and 8's show the same in my manual. My 312 red lines right about where the book shows which is 4200 - 4300.

Go according the marine specs on the timing. The marine version may be cammed for more torque (many marines were) and that may be the difference in the timing spec.

It's been so long since I did a tune up (you know the 28 year old points that are still going strong!!!) that I had a hard time remembering about the timing!! The marks are on the flywheel on the 312. There is a "inspection" cover on the top of the bellhousing that needs to be removed. Look for one on your 6.

Edit: I forgot your flywheel forward. Did you paint over the mark on the flywheel? There should be a grove cut in it someplace.

Edit again: I just looked at you picture of the painted engine. Looks like there's a pointer sticking out of the shroud around the flywheel right about on the top. Is it?

Maybe I could fit one under my current "big and ugly" hatch!
(these were pics from back in June '06. Looks a lot different now).


Na, I'm just kidding anyway, but it looks like even that hatch was still low. And it's getting re-done anyhow...
Hey Phatsat67, there's your windshield again!

Wonder how close "under the box these were?
I think they're actually lower than even the valve covers!