Carburetor choice for MC-6

[Terry Sullivan]

I'm building a few MC-6 engines for my Bug.
Looking for recommendations for the carbs.
Not interested in being the fastest one out there.
I would prefer easy tuning and synchronization - am I dreaming?
Flatback, Tillotson?

Thanks,

terry

[Frank Payne]

They came with a Tillotson HL93A or a small flatback. Either work great stock.

[Terry Sullivan]

thanks for the reply Frank.
I haven't seen too many HL93's for sale.
I'm thinking about one of the newer Tillys - like an HL304
I know it wouldn't be 'period correct', but I wouldn't have to worry about worn shafts, etc.
Would I be stoned or shunned for doing that?

[Dean Seavers]

Terry-

This is strictly my opinion, so weigh it accordingly- but the only possible detriment I can see by not using a 93 is if you intend on making it a perfectly factory correct restoration for shows. Then you might get a couple of points kncoked off, but I'm not even sure there is any show in the country that has adopted standards that are that stringent- at least not at this point.

So if you're building the motor to run, I would think any kind of HL tillie is going to fit the bill and be well within the spirit of period correctness.

The one thing you might want to double check when you order the new carb is that it has the old-style throttle shaft in it. The last two 334s I bought had the new style "reverse pull" type with the pressed on throttle arm- plus no holes drilled and tapped around the mouth for a vintage style velocity stack.

Let me know how it goes! I've got a Mc6 that I need to eventually get to for a McCulloch R-1 kart that I need to get to!

Dean

[Dave Brillhart]

There are loads of HL232's around, used on the early US820 west Bends, that should work perfetly and have the early style body. The smaller bore than the Rotary vale 0.900" carbs would be great for early engines. I have a pile if you want one. Dave

[Tom Smith]

The flat back first appeared on the later Mc-6 and Mc-10 engines, I think the flat backs are what I'd use first over later Tillotsons. They seem more Mcculloch some how than the Tillotsons do.

[Rick Chapman]

Being new to this Vintage Karting, I am lost on why I see so many non-McCulloch carbs on old mac's. I am restoring a Mc6, Mc9, Mc20 and a 91A and they will all be a close to factory as possible. I went through some old Karting World magazines and none of them show a Mc6 with anything but a flat back. If anyone is going to restore these great old engines and karts, then make them as close to the way they were. I feel it's the right thing to do so don't give in to a quick fix, even if it does take a little extra time to make it right. Just my thoughts...

[Dean Seavers]

Rick-

Just my take on it- a.) small flatback parts are difficult to come by and gets to be a problem if you want to run the kart regularly and b.) if you also look at karting world, you'll see that a lot of folks ran aftermarket manifolds with tillotson carbs and at least through the mid-60's, almost every hop-up article had folks put a tillotson as part of the hop up. Your definition of "what was" can change if you're talking about the what was of the McCulloch dealer showroom or the "what was" in the pits at a kart track. Tillotsons were prevelent in karting from its inception. And they did come stock on the early Mc6. As a matter of fact, I've got the February '61 Karting World right in front of me and the Mc6 on the cover has a tillotson, and the twin Mc6s on stock manifolds on the Hovey Hawk test inside have tillotsons on them as well.

Plus for those of us who run alky, it's easier to get an alky tillotson rather than try to either find a flatback that's been converted to alky (with a varying degree of craftsmanship and effectiveness, no less) or grab a drill on a regular gas flatback and go to town- not to mention it makes for one less stock flatback on the planet for the guys who want to run a gas version on their Mac.

I've got both types of carb and they're both cool. But tillotsons are certainly as period correct as flatbacks- and flatbacks aren't always even factory correct.

Dean

[Tom Smith]

Here's the rundown according to Mcculloch from Feburary 1962 on the only Mcculloch kart engines to use Tillotson carbs.
Mc-5 first 6000 units were supplied with HL63BX carb, Mcculloch P/N 48730
Mc-5 serial #6001 and up supplied with HL93A
carb, Mcculloch P/N 48730A
early Mc-6 (as in left over Mc-5s) supplied with HL93B carb, Mcculloch P/N 48730B and replaced with Mcculloch carburetor P/N 48811. (flat back)
I think what this mumbo jumbo means is the Hl93B was the same carb the later Mc-5s used but it came on an Mc-6.

[joelwey]

Anyone out there got the size and drill specs for the HL93's?
Throat/venturi and hi/lo,idle jet,etc.For gas,of course.
regards,Joel