Summary of Contents for Demon 625 Street Demon Carburetor 1900
- Page 1 625 STREET DEMON™ Part Numbers: 1900, 1901, & 1902 INSTRUCTION MANUAL LIT701 US Patent # D648746S www.demoncarbs.com...
-
Page 2: Table Of Contents
INTRODUCTION ..................................3 Recommended Parts and Accessories ..........................3 Removal of Existing Carburetor ............................3 Installation of Street Demon™ Carburetor ......................... 4 Connecting the Throttle Linkage ............................5 Connecting the Transmission Linkage ..........................5 GM TH350, 200R4 /700R4 ..............................5 Ford Kick-Down Linkage .............................. -
Page 3: Introduction
Whether it is street / strip performance, or just getting the most out of your hot rod, the Street Demon™ will give you optimum performance. This manual will discuss the special points and unique features of the carburetor, and the correct procedures for proper installation and tuning. -
Page 4: Installation Of Street Demon™ Carburetor
Figure 1 Optional Fuel Inlet Fittings Street Demon™ 9/16"- 24 threaded fuel inlet boss accepts the following optional fittings: FITTING TYPE MANUFACTURER PART NUMBER... -
Page 5: Connecting The Throttle Linkage
If you are unfamiliar with overdrive transmission TV cable adjustments, consult a qualified transmission expert. Failure to properly adjust the TV cable on overdrive transmissions can lead to poor shifting and / or transmission failure. Demon Carburetion assumes no responsibility for transmission damage or failure caused by improperly adjusted TV cables. -
Page 6: Ford Kick-Down Linkage
Demon has you covered. Part # 1951 Street Demon TPS kit is designed to bolt directly to your new Street Demon™ carburetor to provide the needed TPS signal to an electronic transmission. Consult the installation manual for the 1951 Street Demon TPS kit for installation and adjustment instructions. -
Page 7: Vacuum Lines
Vacuum Lines All Street Demon™ carburetors have four vacuum sources on the baseplate that can be used for PCV, distributor vacuum, diagnostics, or any other vacuum operated accessories (Fig. 8). The large 3/8" vacuum port, as well as the small 3/16”... -
Page 8: Air Cleaner
Air Cleaner 1. With some air cleaner configurations, it may be necessary to use an air cleaner spacer to provide adequate clearance between the carburetor and the air cleaner. Depending on the overall height, obtain the proper length 1/4 x 20 stud (supplied) and install in the carburetor air horn and trim as necessary. -
Page 9: Fuel Pressure
3. The 14” Demon air cleaner (Part # 786004) is designed to clear the choke plate linkage on all Demon carburetors. If you use another brand of air cleaner / air cleaner gasket or air cleaner spacer, it is necessary to make sure that the... -
Page 10: Performance Tuning And Adjustment
Once you have completed the initial installation, and preliminary adjustments, you are now ready to test the vehicle and evaluate any other possible tuning adjustments. Information on changing the configuration or fuel metering of your Demon is also included in this section. -
Page 11: Main Metering Tuning
Located under the choke flap, the accelerator pump nozzle has two calibrated holes which discharge the fuel into the venturii. The Street Demon™ comes with a .031” discharge nozzle from the factory. If more fuel is needed, a larger discharge nozzle can be used. If less fuel is needed, a smaller discharge nozzle may be used. -
Page 12: Tuning
There are a few different areas that need to be looked at separately when it comes to tuning a Street Demon™... -
Page 13: Steady State Cruise Tuning
Steady State Cruise Tuning Earlier, the theory of how the main metering system works was explained. During steady state cruising, there is enough vacuum to overcome the step-up spring tension so the rod is in the down position and the lean step is in the jet. It is best to drive the vehicle at a steady state and record the AFR or vacuum gauge reading in 10 MPH increments. -
Page 14: Long Duration Camshaft Tuning
Tuning for Elevation Street Demon™ carburetors are calibrated at sea level. When going up in elevation, the air is thinner and the carburetor may run rich. As a general rule of thumb, for every 2,000 ft. in elevation, the metering rod diameter should be increased .002”... - Page 15 4. Disconnect the choke linkage by carefully removing the E-ring retainer from the choke rod (Fig. 22). 5. Disconnect the accelerator pump rod from the pump arm by carefully removing the c-clip (Fig. 23). Figure 22 Figure 23 6. Remove the six Phillips head screws from the bottom of the carburetor as circled in (Fig. 24). 7.
-
Page 16: Winter Fuel
Always use a new microfiber cloth for polishing or unwanted scratches can occur. The composite fuel bowl on the part #1901 Street Demon™ does not require any type of polishing; cleaning with a mild soap and water will bring it back to new condition. - Page 17 1) Big vacuum leak somewhere. 1) Correct the vacuum leak. Make sure you haven't forgotten to Engine starts, then hook up a hose somewhere. Base gasket may be wrong one or races for a few on wrong. seconds and then dies every time.
- Page 18 Drivability 4) Ignition timing retarded. 4) Set to factory specs. Make sure advancing correctly. Condition 5) Idle speed set too fast & 5) Richen up the idle mixture, reset the idle speed to factory mixture is too lean (common) specs, then reset the mixture using the lean drop method. 6) EGR valve stuck on or coming 6) Inspect hose routing to EGR valve &...
- Page 19 15) Poor driving habits. 15) Reduce speed, quick acceleration, screeching around corners etc. 16) Float level too high, or float 16) Set to factory recommendations, & check float weight, partly sunk. replace if necessary. Factory setting, with air horn upside down, is 1.01”+/- .015”...
-
Page 20: Demon Carburetion™ Limited Warranty
Carburetion™ offers no other warranties expressed or implied beyond this Limited Warranty. In the event of an alleged defect in material or workmanship, the responsibility of Demon Carburetion™ is strictly limited to the repair or replacement of the defective product. Demon Carburetion™ has no other obligation expressed or implied.
Need help?
Do you have a question about the 625 Street Demon Carburetor 1900 and is the answer not in the manual?
Questions and answers