MTFCA Forum

I've owned this 1906 Orient for many years. It came with the original carb and a selection of miscellaneous small-engine carbs. The one shown in the photos below was on the car as acquired. I did experiment with the others back then, including the original, and this one worked best. "Best" in this case meaning least unsatisfactory. My understanding is that the original carb dated to an era when gasoline was far more volatile, and will not work satisfactorily with modern fuels.

Anyway, I'm hoping someone here will recognize this carburetor, and have experience/suggestions as to proper adjustment. As is is, the choke needs to be mostly closed for the engine to stay running. Two adjustment screws: yellow and blue. The green arrow points to a bit of heater hose that keeps the carb from vibrating at the end of its long intake tube. Fuel seeps out from this area when starting.

Nifty, Chris

I believe your info on old fuel is upside down, as the fuel was often oilier and even more often adulterated with kerosene to boost the General Store's profit margin

It is nearly certain that the upper adjustment is an idle mixture screw and the lower is the main jet. If it only runs with the choke mostly closed, there is an obstruction in the idle circuit which requires a huge vacuum level to pull up fuel from the main jet. This would be true if "wide open" (what ever that entails) will run with minimal or no choke (and the main jet is not clogged, too)

Octane wasn't something people talked about in 1906, but there were different kinds of gasolines, with boiling points ranging from 125-200F...some was for internal combustion engines and some was "stove gas". There was a precipitate from natural gas production (I think) called "drip gas" which was used sometimes.

I think modern gasoline will be fine in your carb, but it needs a thorough cleaning.

this book might shed more information on your carb and fuels of the day: Hiscock, Gardner D., GAS, GASOLINE AND OIL ENGINES, The Norman
W. Henley Publishing Co., New York, 15th Edition, 1906.

https://www.amazon.com/Gas-Gasoline-And ... 1559182032

Looks like your carb. is from a early 10 horse Briggs and Stratton engine.

Chris's comments on early fuel are correct. The fuel at the turn of the century was very volatile. When distilling crude oil, the first fraction is high volatile, low boiling point gas, the comes the heavier fractions with lower boiling points such as kerosene. When kerosene was worth more then gasoline at that time, the tap was switched to kerosene early and the gasoline was high test stuff.

Later when gasoline was worth more than kerosene, the tap was changed later and the gas quality degraded to nearly that of kerosene.
The problem was solved in the late '20's when catalytic cracking of the heavier crude fractions into lighter fractions improved the yield and quality of gasoline, along with the addition of tetraethyl lead to reduce knocking to help engines run with higher compression rations.
Early gasoline was so easily vaporized, that the early cars were able to use surface carburetors where the air passed over the surface of the gasoline and picked up enough fuel to run the engine without the use of spray needles or venturis.

For Chris's issue. Take a close look at the inside design of the carburetor. Some of these early carburetors are essentially constant cross section air passages which do not develop the needed negative pressure to pull the gas into the airstream like later venturi carburetor design. Several of them used a spring-loaded air valve on the inlet end of the carburetor. The spring was a very light spring with a thumb nut for adjustment. The carburetor needed to be adjusted to produce a small negative pressure in the carburetor body to pull the fuel into the air stream.

It may also be possible that the fuel inlet port/needle passage is too small a bore to pass the needed fuel for this engine at the speed and inlet air pressure that it operates at. I would also suggest checking the fuel path for possible flow restrictions.

Thank you all for the suggestions re my current and original carbs, also the further background on early fuels.

Some years ago I read, but neglected to photocopy, a procedure for testing the quality of gasoline prior to purchase from an unknown source (drugstore, etc.) early in the last century...

The motorist was instructed to take a cupful of the fuel in question and throw it high in the air — if it had pretty much evaporated before hitting the ground, the gasoline was deemed to be sufficient quality for use.

That would be an interesting thing to try at our neighbourhood Shell.

I'll report as the carb project progresses.

Jeff and Chris

you are of course correct on volatility. I can only think that my eyes and brain were seeing "octane".

We have liftoff!

Jim Sims had the key to getting this thing on the road today. There are a wealth of videos and pages dealing with Briggs and Stratton carbs, and while the newer ones look different the adjustments same the same. And similar in fact to Model Ts, in that the initial settings are 1-1/2 turns from closed and fine tune from there.

Anyway, the old heap is probably running as well as it ever has for me and I had enjoyed a nearly trouble-free four mile round trip to the nearest A & W for Saturday Cruise-in.

Video link https://youtu.be/jQvhEAE146g to a driveway walk-around while running. Specs and further info in the video description. Thanks again to all who posted.

That's a modern-era, pre-EPA carburetor. It will work well with most any gasoline available today if it is working correctly, adjusted correctly, and sized appropriately for the engine. If your vehicle's engine has air leaks in the intake tract, including at the intake valve guide, it may cause problems. Some early engines with atmospheric, or "automatic" intake valves could develop severe wear at the intake valve guide. Some kind of intake air heat stove arrangement might also be helpful. The intake valve spring tension may also be critical to good engine operation.

That car is great, thanks for sharing.

Chris, nice car thanks for sharing.
Scott, thanks for finding me an exciting 'beach read'. jb

[attachmeTry this. Not to exact BS carb, but all of that style adjust the same. Hope it helps.

I would ignore the fast idle rpm spec when using that carburetor on a 1906 Orient...

This was out of a B&S engine manual. Only posted for to ID as to what did what on that type of carb. Dan