Terrible fuel economy on Vaporizer carb

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Model T Ford Forum: Forum 2016: Terrible fuel economy on Vaporizer carb
Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Horlick in Penn Valley, CA on Sunday, July 03, 2016 - 10:00 pm:

I goofed up and started a thread not realizing I was in the classified section. Sorry, so I am moving it here:




I have recently finished some significant work on my 1927 pickup ("Rusty"). Amongst other work I placed new rings, lapped re-timed and set valves, replaced the low drum, re-bored bushings turned all three drums then static and dynamically balanced on all drums, replaced re-bushed and balanced triple gears, had generator rebuilt, recharged magnets, replaced con-rods, changed to another straightened pan with a replacement hogshead, milled field coil ring and re-shimmed, trued transmission shaft, etc.

I expected to have a rocket of an engine, but alas, with the old Holley Vaporizer carb on there I have a pretty average model T. All is well, but starting is difficult. I have pretty much run it down to the choke not being effective enough.

Yesterday I had to run some tools out to a friend and them meet my wife at a restaurant. Good time to use the T and to be sure I'm ready to use Rusty for transportation tomorrow, July 4, for our 40th wedding anniversary. Rusty had the usual difficulty starting... gas turned on, 3-4 pulls on choke, then 4-8 pulls with ignition set to battery. After driving about 4 miles I parked at home and shut off the fuel.

This morning I wanted to do another test drive, I have about 15-20 miles on the full tank so I expected to see around 8 gallons in the tank. My dip stick shows about 2.5 gal! Man this Vaporizer usually gets around 20 mpg, now it is getting 2.6 mpg!!!!!! I proceeded to turn on the gas, choke and then try to start... only then noticing a bit of a fuel leak.

So do you think you can find my excess consumption problem... if you can then you must be an expert on Holley Vaporizers!

TH





By Dan Hatch on Sunday, July 03, 2016 - 07:40 pm:

Lost the drain valve




By Terry Horlick in Penn Valley, CA on Sunday, July 03, 2016 - 08:29 pm:

Dan, pretty good.... answer in just 3 minutes! I think I found the problem faster than that, but then I could see where fuel was leaking!

I had a replacement fuel shut-off on the shelf, now it's on the car. And I have discovered that choking causes fuel to drip out of the intake horn orifice. So I can see there is definitely an issue there. I assume if I solve that my Vaporizer will be back to it's previous stellar performance.

TH


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Horlick in Penn Valley, CA on Sunday, July 03, 2016 - 10:17 pm:

Forgot to include the photo... how else can you answer?



TH


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Eubanks, Powell, TN on Tuesday, July 05, 2016 - 07:48 am:

Good work Terry. Since I am running two of them and have run them for years, they do work. Had an engine down and the vap. on the floor for a while. When I put everything back together, no more leak when not running. I had to turn the gas off before that and now somehow its "fixed".


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Tuesday, July 05, 2016 - 10:04 am:

That looks like the drain plug is missing. If so, I am surprised you got any gas mileage at all.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Horlick in Penn Valley, CA on Tuesday, July 05, 2016 - 03:27 pm:

Problem solved!

My goal was to use the T yesterday to go to the lake for a full day of family, swimming, fireworks on our 40th wedding anniversary. Didn't happen, I couldn't get Rusty to run and spent several hours in the morning rebuilding the Holley Vaporizer carburetor. No dice, refuses to run.

So last night after the fireworks were done I perused the literature I have on Vaporizers and searched out old posts on the forum. I found what looked like the answer.

Note here: I have a full set of the MTFCA pamphlets including "The Ford Carburetor" 1988, and 1995. (I have two because I picked up some extras inexpensively at a swap meet). First comment is the answer was in the 1995 book and not in the 1988 edition. These books do vary on their content, so MORE IS MORE BETTER!

The clue I needed was provided by William Cuddy in 2007 (http://www.mtfca.com/discus/messages/29/27744.html)

One observation I made in the course of assembly, (that may be of interest to the next T Man who tackles this job), is to be aware that the vaporizer drain valve body is unique, differs from the ordinary NH drain valve body, and is essential to make the unit operable.


With William's clue I went to the 1995 pamphlet and confirmed the suggestion on Page 25:

Drain Valve Body
(Part Number 6291.) This is a truly unique part of the vaporizer carburetor. While drain plugs from other carburetors will fit, the Vaporizer valve body itself is different, even though the same drain plug (the valve itself) is used. Ensure that this part is correct. It is mandatory that the Drain Plug seal the bore area directly below the Main Nozzle in order that fuel can enter this chamber through the Adjusting Needle and Seat. The area on top of the Drain Plug that screws into the Manifold Cover and Float Bracket Assembly should be solid-i.e. there should not be a hole in this end of the drain plug.


Well there you have it. On Sunday I grabbed a new drain valve from the shelf and swapped it in for the old one. Today I pulled it out and shot a set of photos for this post. The original valve body is on the left the NH replacement is on the right.



Sure enough there is that pesky little hole. I had inadvertently installed a NH plug into my Vaporizer thereby immobilizing my car!

I replaced the original Drain Plug body and the new valve core /handle. The car starts right up and runs just fine.

So Vaporizers run the car well and with good economy, but everything has to be right.

Take Home Lesson: When your car suddenly refuses to function correctly, look at the last thing you touched or changed!

IMHO
TH


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