UPDATE 5/27/24-Experimental alternative to a clear tube when setting fuel level.

hardrockminer post=846635If the smell is a concern and potential explosion negates any volatiles...Why not use straight water?  You can simply calculate a different setting.  Without doing the math it would be around 4.5 mm plus or minus 1.0 mm.

Odor is less a concern than fire safety and toxicity.  Handling can be mitigated using nitrile gloves, but fire safety from vapor is foremost & airborne toxicity must be kept in mind.

  We have an ancient, whole-house, 1/2 horse belt-driven attic window fan we place at the outside basement door during warm weather that moves a huge amount of air from inside to outside.  Enough that if we don't open the basement (or any) window, the negative pressure in the house creates a back draft in the water heater flue that usually extinguishes the pilot light.  Opening the basement (or any upstairs) window & running the fan when it's cold outside is a non-starter.

We documented the results using tap water in the OP.  See pics.  We'll experiment again this year using distilled water to eliminate the possible variables and mineral contaminants in tap water & calculate from there, switching between water and fuel repeatedly (at least three times) to confirm results.  We just have to do it outdoors while switching between water and fuel while experimenting.

Still looking for vessels that have a bottom drain nipple like the one in the video.

Good Ridin'
slmjim & Z1BEBE 

wrote:

E15 gasoline has an SG of about 0.76, but gasoline in general can vary between about 0.70 and 0.80, depending on grade, additives and time of year.  Methyl hydrate has an SG of about 0.79, so on the higher end of gasoline and about 4% higher than E15 gas.  The higher SG would cause the floats to ride higher and close the float valve a little sooner.  A difference of 4% on 3.5 mm is 0.14 mm.  I doubt that anyone could visually detect that difference, and in any case it is well within the plus or minus 1.0 mm margin of error.  Sounds like it's worth a test.


 

Straight ethanol is also .79 SG and I think would be less toxic via inhalation than gasoline and somewhat less volatile. 
 

I've been tempted by these new releases from PMC out of Japan.  The go on Keihin CR carbs:




 

Hello everyone
sorry for my bad english
I am tinkering with fuel level of a z1 carb rack and i am studying all the great info here

I have a thought about to determine the real fuel level to aim for

I think what is crucial is to understand if the horizontal holes of the choke tube coming down from the carb body and are designed to be clear of fuel or under fuel level

Those holes are just around there where the fuel level is supposed to be

In my opinon they look like vent holes which are supposed to be above fuel level just like the horizontal holes in the emulsion tube and in the pilot jet.

If this is correct then the fuel level has to be set just below those holes and the glass method will come very useful for this process

Does it make sense to anyone?

Thank you

This project has not come to a standstill.

We obtained the lab hydrometer and graduated cylinder needed to test the specific gravity, sometimes also referred to as relative density, of various fuels and other fluids back in mid-2023, and have made significant progress in finding safer alternatives to gasoline when setting float levels in a climate-controlled (heated in winter) indoor / residential basement shop environment.

To date, we've been looking at liquids that match specific gravity & float levels as closely as possible to pure, 100% gasoline. Using 100% gasoline should eliminate whatever variability might occur with 10% ethanol summer & winter blends. 

There is a gasoline fuel injector calibration fluid suggested earlier in this thread that is very promising so far, but at $78.00/gal. the stuff isn't cheap. Once we have a repeatable baseline for that, as well as 100% pure gasoline, we'll begin testing distilled water in an attempt to ascertain the exact difference in actual float level.

Over the last 6 months, a local custom lab equipment glassblower has produced a handful of dummy 'float bowls' (modified lab beakers) for our testing based on our ongoing specs & suggestions.  Here is the first rough prototype from late last year:


The glassblower has been very interested & cooperative in this project, offering good suggestions as we try different configurations of graduation marks & beaker depths.  Different configurations can be produced based on need.  We're only testing for Z1 VM28SS carbs.

Every prototype incorporates a drain barb close to the bottom that a 3/8" ~ 5/16" hose can be attached to for convenience & neatness.  He also applies a fuel-proof ceramic graduation line 3mm below the top edge of the vessel, prior to kiln firing, for easy visual evaluation of liquid level.  We're also evaluating graduation line colors (black & green so far), as well as a solid line all the way around vs. a broken line at 3mm and,  a version with staggered broken lines at 3mm and 4mm below the top edge.

We posted a request in the 'WANTED' sub-forum for a set of 4 old carb holders suitable for mounting a rack of Z1 VM28SS carbs to a board to allow for some vertical adjustability, because the prototype glassware varies in height a little.  Being able to support & vertically adjust a rack of carbs will ease testing & development of this custom glassware significantly.

Been a fun & educational project so far.  Not cheap, but education usually comes with costs. There will be some additional, very detailed,  arcane & (maybe) borderline eyes-glaze-over stuff to come, likely in a new thread.

Good Ridin'
slmjim & Z1BEBE