Quote:
Originally Posted by drolston
The density of E10 gas is about 2.3% less than straight gasoline. I doubt that would raise the fluid level in the bowl by very much.
Which raises a question in my mind I have had for years as to why there is such obsession with precision is setting float level. With steep hills and sharp turns and bouncing around on rough roads, the fuel in the float bowl is going all over the place, and yet the flathead continues to run smoothly. The size of the jets controls the flow, not the depth of the fuel in the bowl.
Opinions?
|
I find the alcohol fuel expands more than the old gasoline, and will flood the carburetor after shutdown when the engine is getting heat soaked. Lowering the float eliminates this problem.
Also, my memory is JWL experimented with float settings in his very methodical and documented dyno testing sessions and found fairly large changes in our old carburetors didn't affect fuel ratios. Carburetor design will have an effect on this, and this finding should not be universally applied to other engine types and carburetor types.
Quote:
Originally Posted by drolston
It would be fun if someone with an air/fuel indicator on their flathead ran a test to see how much fuel level in the bowl affects mixture.
|
I did not do a before test, but I did use my portable O2 sensor test on the 37 after lowering the float to make sure it wasn't running lean (it wasn't). I also found the initial ignition timing advance on the side of the helmet distributor affected idle vacuum and O2 readings much more than I expected. This was 10+ years ago and I don't remember all the details, but do remember being happy with the final result.
Quote:
Originally Posted by busmania
Interesting chatter about floats!
Does anyone think floats being wrong would cause dripping after running? I haven’t had dripping since I started this thread and I drove it pretty long today (but it’s also now finally not getting hot when idling at lights and such).
|
This matches my experience. Heat soak causes the alcohol type fuel to expand in the float chamber, running down the carburetor internal passages, pooling on top of the closed throttle plates, and running out the throttle shaft. Lowering the float solved this problem for me. South Texas is hot enough during most of the year that I cannot avoid heat soak.