Overview:
This booklet provides a comprehensive guide for understanding and adjusting the Marvel Model “S” carbureter, specifically designed for Series 691 Nash Sixes. The booklet focuses on the carbureter’s construction, starting procedures, and most importantly, the intricate heat control system. The carbureter utilizes exhaust gases to heat the mixing chamber, ensuring complete fuel vaporization and optimizing fuel economy. The booklet explains the two primary “Heat Setting” options, “No. 1” for maximum heat, and “No. 2” for reduced heat, enabling the driver to adapt to different weather conditions and fuel types.
The text also emphasizes the importance of proper carbureter adjustment, highlighting potential issues caused by over-rich or lean fuel mixtures. It provides a detailed step-by-step process for achieving the optimal carbureter setting, ensuring smooth engine operation, optimal power delivery, and fuel efficiency. The booklet concludes with a parts price list for both the Model “S” and its predecessor, the Model “K,” offering guidance for repairs and upgrades.
Key Findings:
- The Marvel Model “S” carbureter is designed for optimal fuel economy and performance.
- The carbureter utilizes exhaust gas heat to ensure complete fuel vaporization.
- Two “Heat Settings” allow drivers to adjust for varying weather conditions and fuel types.
- Proper carbureter adjustment is crucial for optimal engine performance and fuel economy.
- Over-rich or lean fuel mixtures can cause issues with engine performance and fuel efficiency.
Learning:
- Heat Control: The booklet teaches the importance of heat control in carbureters for achieving optimal engine performance and fuel efficiency. It explains the two “Heat Setting” options, “No. 1” for maximum heat, and “No. 2” for reduced heat, allowing the driver to adjust for different weather conditions and fuel types.
- Carbureter Adjustment: The booklet provides a detailed step-by-step process for adjusting the carbureter, including the air screw, needle adjustment, and choke settings. It highlights the importance of setting the needle to the factory-calibrated position for optimal performance.
- Fuel Mixture: The booklet explains the importance of maintaining a proper fuel mixture for efficient engine operation and fuel economy. It outlines the potential problems caused by both over-rich and lean mixtures.
Historical Context:
This booklet was published in 1923, reflecting the era of early car manufacturing and the development of carbureter technology. It specifically targets owners of Series 691 Nash Sixes, a popular model during that time. The booklet emphasizes the importance of fuel economy, a crucial concern in an era of limited fuel availability and rising prices.
Facts:
- Carbureter Function: The carbureter measures and mixes fuel with air, creating a combustible gas for the engine.
- Marvel Model “S” Features: The Model “S” carbureter features an automatic air valve, heat control, and a fuel metering valve.
- Heat Control System: The carbureter uses exhaust gas heat to vaporize fuel completely, minimizing fuel consumption.
- Heat Setting No. 1: The “Heat Setting No. 1” option provides the most exhaust heat possible, ideal for most seasons.
- Heat Setting No. 2: The “Heat Setting No. 2” option reduces the amount of heat applied to the carbureter, suitable for hot climates or high-test gasoline.
- Needle Adjustment: The needle adjustment should be set to the factory-calibrated notch for optimal performance.
- Air Screw Adjustment: The air screw controls idle speed and should be adjusted for smooth engine operation.
- Choke Function: The choke button enriches the fuel mixture for easier starting in cold weather.
- Over-Rich Mixture: An over-rich mixture can cause engine misfiring, black smoke, and a strong odor.
- Lean Mixture: A lean mixture can cause overheating, loss of power, and fuel inefficiency.
- Interchangeability: The Model “S” carbureter is interchangeable with the Model “K” used on earlier Nash Sixes.
- Model “E” Replacement: The Model “S” can improve the performance of older Nash Sixes equipped with the Model “E” carbureter.
- Distributors: The booklet lists distributors across the US that carry Marvel carbureter parts and services.
- Export: Overseas Motor Service Corporation handles Marvel carbureter exports.
Statistics:
- Carbureter Assembly Price: The Model “S” carbureter assembly costs $22.00.
- Complete Heat Equipment Price (1919-1922 Nash Sixes): The complete carbureter and heat equipment for older Nash models costs $30.00.
- Damper Body and Stove Assembly Price: The damper body and stove assembly for older Nash models costs $8.00.
- Float and Lever Assembly Price: The float and lever assembly costs $0.75.
- Float Valve Assembly Price: The float valve assembly costs $0.45.
- Gasoline Adjusting Needle Assembly Price: The gasoline adjusting needle assembly costs $0.50.
- Bowl Cover Assembly Price: The bowl cover assembly costs $0.75.
- Flusher Assembly Price: The flusher assembly costs $0.15.
- Brass Bowl Assembly Price: The brass bowl assembly costs $6.00.
- Strainer Assembly Price: The strainer assembly costs $1.00.
- Dash Pot Plunger Assembly Price: The dash pot plunger assembly costs $0.80.
- Metering Pin Housing Price: The metering pin housing costs $0.15.
- Metering Pin and Lock Wire Assembly Price: The metering pin and lock wire assembly costs $0.45.
Terms:
- Carbureter: A device that mixes fuel with air to create a combustible mixture for the engine.
- Heat Control: A system that utilizes exhaust gas heat to vaporize fuel completely and optimize fuel economy.
- Heat Setting: A selectable setting that determines the amount of exhaust heat applied to the carbureter.
- Throttle Valve: A valve that regulates the amount of air and fuel mixture entering the engine.
- Needle Adjustment: A setting that controls the amount of fuel delivered by the low-speed nozzle.
- Air Screw: A screw that controls the amount of air entering the carbureter and adjusts idle speed.
- Choke: A device that enriches the fuel mixture for easier starting in cold weather.
- Over-Rich Mixture: A fuel mixture with too much fuel, causing engine misfiring, black smoke, and a strong odor.
- Lean Mixture: A fuel mixture with too little fuel, causing overheating, loss of power, and fuel inefficiency.
- Exhaust Manifold: A part of the exhaust system that collects exhaust gases from the engine.
Examples:
- Heat Setting No. 1: This setting should be used in most weather conditions for optimal fuel economy and performance.
- Heat Setting No. 2: This setting is recommended for hot climates or when using high-test gasoline, to reduce the amount of heat applied to the carbureter.
- Needle Adjustment: The needle adjustment should be set to the factory-calibrated notch, which is typically about one turn from its seat.
- Air Screw Adjustment: Turn the air screw in slowly until the engine starts to roll, then back it out until the engine hesitates. Fine-tune the adjustment until the engine runs smoothly.
- Choke Usage: Pull out the choke button fully to start the engine in cold weather, then release it gradually as the engine warms up.
- Over-Rich Mixture: If the engine is misfiring, producing black smoke, and has a strong odor, it may indicate an over-rich fuel mixture.
- Lean Mixture: If the engine is overheating, losing power, and consuming more fuel, it may indicate a lean fuel mixture.
Conclusion:
This booklet is an essential guide for anyone owning a 1923-24 Series 691 Nash Six. It provides a detailed explanation of the Marvel Model “S” carbureter, focusing on its intricate heat control system and the importance of proper adjustment for achieving optimal engine performance and fuel economy. The booklet highlights the importance of understanding fuel mixture ratios and how to adjust the carbureter for different weather conditions and fuel types. By following the instructions provided, owners can ensure their Nash Sixes run smoothly, efficiently, and with maximum power output.