Timing on gas and alcohol flathead

High side

New member
Is there a difference in timing for a gas engine and a alcohol engine it’s was a alcohol engine and I bought a gas carburetor brand new tillotson. it will idol but won’t rev up and run full throttle
 

95 shaw

Premium User
You should probably reduce ignition timing.
It will run as it is, but you may be giving up some power.

If it won't rev. add fuel to low side.
With a tillotson, do not expect clean lean idle.

Richen low side to get to rev. then set idle speed.

Plug may be too cold also.

just some thoughts.
 

High side

New member
I’m pretty sure it’s a fuel pump issue it’s a square walbro pump .Timing Checked out ok.it runs better when the high side is all most all the way out.
 

flattop1

Dawg 89
which tilly ?
There are differnt drill patterns that determine the intended use .
Some are even designed to be tuned by the end user.
 

High side

New member
I put a inline fuel filter in so I could monitor fuel flow and after starting it there’s no fuel in the filter it will set on the stand and idol I adjusted low and high and it runs smoothly it will rev up wot but when on the track under load it will die with any movement of the throttle I’m new to these carbs so just trying to figure out how they work properly maybe I should just buy a mikuni and be done with tillotson everyone I race with runs the mikuni and has no issues but they run stock gas tanks with no fuel pump
 

High side

New member
which tilly ?
There are differnt drill patterns that determine the intended use .
Some are even designed to be tuned by the end user.
So basically a engine builder would take the carb a part and drill different holes for fuel and air flow for the application?
 

95 shaw

Premium User
How could this be the problem ?explaining would be better
Reread the description given in the ad.

The carb is sold with drill pattern not full size, so builder can customize pattern for particular application.
If this is a new carb, for that model number, the work has not been completed.
EC offers a version with the drill patterns set up reasonably close for your particular application.
Of course, these are more money.

Long story short, if you buy the cheap version, you sometimes get what you pay for.

Sometimes, a used version from a working setup is a good buy.
 

High side

New member
Ok that helped as I did read the ad before I bought it but I guess I really didn’t pay attention to it’s exact words so basically I need to find a builder and have them tune it to my engine
 

High side

New member
so Next question is the engine was a alcohol engine it came with a tillotson alky carb is it possible to put the plates off the gas carb on the alky carb body both are hL series carbs seeing how that carb was the original carb for the engine btw you’ve been great with the answers to my questions I’m starting to understand a lot now I messed up buying a builders carb you live and lean
 

95 shaw

Premium User

Post 13 answers your question.

Further, the plates are, for all intents and purposes, a fuel pump. the metering is primarily done in the carb body.
 
Last edited:

CarlsonMotorsports

Premium User
The drill pattern is under the welch plug in the body of the carb -- the fuel holes are drilled directly into the venturi area of the carb body and should not be modified by anyone without a LOT of experience working with these carbs.
No, there's nothing you can do with that alky carb (except run it on alky) at this point.

Yes, you'd do better with a Mikuni, they're pretty much plug-n-play.
If you want to run the Tilly, send the 304WX back to EC and have them re-drill it for your application - they will do a fine job on it for you (at add'l expense.)



-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
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765-339-4407
bcarlson@CarlsonMotorsports.com
 

CarlsonMotorsports

Premium User
...oh, and the ignition timing will be just fine right where it was set for alky - no difference necessary until you get to a LOT more compression and much bigger cam/rpm.
 
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