Marvel Carburetor Disection

[Jeff in BC]

I'll be disassembling what I believe is an early carburetor using the following as references:

- Marvel-Schebler TXS - DTXS Service Manual (1952) http://www.oldcarmanualproject.com/m...S-DLTX-TSX.pdf
- Patent 1536043 (1928) http://www.freepatentsonline.com/1536043.html

I hope to be able to probe and follow all passages through the carb and compare them to the service manual and patent.

Components on the photos will be numbered with the same system as used in the Service Manual. This will allow the use of some of the diagrams in the manual; I will also use Marvel's terminology. Photos on the site are at a reduced resolution, if anyone would like full sized copies please PM me with your request.

Now on to the carb.

The Float System



Photo 1 - Float system with components identified:
1 - Float Bowl
2 - Float
3 - Float Valve
4 - Float Valve Seat
6A - Gas Inlet Model A
6B - Gas Inlet Model B
7 - Float Bowl Vent
8 - Float Valve Drain

Note - Fuel entry fitting is shown at the Model A position (6A). This may be moved to position 6B for use on a Model B.
Troubleshooting note: If you believe you have a fuel flow problem, the plug at the unused gas inlet (6B on above carb) may be removed to check for good gas flow. This is better than removing the gas line as it doesn't disturb anything in the system.



Photo 2 - Fuel inlet fitting/filter



Photo 3 - Close up of float and float valve and seat (valve open)
2 - Float
3 - Float Valve
4 - Float Valve Seat



Photo 4 - Top half of carb with all float components removed and fuel passages shown.
2 - Float (and hinge rod)
3 - Float Valve
4 - Float Valve Seat (and gasket above)
6A - Gas Inlet Passage for Model A (green wire)
6B - Gas Inlet Passage for Model B (white/green wire)
7 - Fuel Bowl Vent Passage (blue wire)



Photo 5 - Diagram from Service Manual

The above diagram is on page 2 of the Service Manual along with a full description of operation.



Photo 6 - Measuring float level

Service Note: Setting float height, the float should be parallel to the upper gasket surface. I used the float seam to gasket surface (15/16"). In the photo it looks a little off but this is camera distortion. If measured as shown the clearance between the gasket surface and the top of the float is 1/4". The height from the gasket surface to the bottom of the float is 1 3/4".



Photo 7 - Measuring the fuel level

I measured the gas level using witness marks in the fuel bowl. This distance is ~11/16" from the gasket surface to the marks in the bowl.

All for now
Jeff