Quick Fuel Technology MARINE SERIES CARBURETORS User Manual



Installation Instructions



M-650 650

CFM, w/Electric Choke !


M-750 750 CFM, w/Electric Choke


M-800 800

CFM, w/Electric Choke !

M-850 850 CFM, w/Electric Choke


! !


M-4710 1050 CFM, QFX, 2 Circuit

Please Stop and Read these Instructions before proceeding. If you do not fully understand the installation and tuning instructions you should seek professional help. Failure to follow the proper installation and tuning may result in damage or injury.

Quick Fuel Technology®

129 Dishman Lane

Bowling Green, KY 42101 270-793-0900 www.quickfueltechnology.com

©2012 P/N 99-MSeries

Quick Fuel Technology MARINE SERIES CARBURETORS User Manual

Quick Fuel Technology would like to congratulate and thank you for purchasing this carburetor. We feel you have purchased the finest marine performance carburetor currently on the market. If you need assistance please call the QFT Sales and Tech Support staff @ 270-793-0900, Monday through Friday 8AM – 5PM central time.

This QFT™ carburetor has been ran on an engine to insure all components are functional. The calibration should be very close for all adjustments. Different engine combinations could require adjustment of idle mixture, idle speed and main jets. The fuel level was set with 6 ½ lbs. of fuel pressure. The recommended fuel pressure for this carburetor is 6 ½ PSI.

Note: This QFT™ carburetor has not been submitted for emission testing, therefore it is not C.A.R.B. (California Air Resources Board) legal in all 50 states - please check with local authorities regarding the use of this carburetor.

Remove old carburetor:

1.Disconnect negative battery terminal to prevent any accidental arcing in the presence of fuel.

2.Remove air cleaner, PCV hose and any other vacuum lines connected to the carburetor. For future reference identify the vacuum lines to ensure proper re-connection.

3.Remove fuel line(s)…be careful not to twist fuel line(s) when removing fuel inlet fitting(s), use penetrating oil or similar chemical to assist in breaking the fuel inlet fitting nut loose. Protect the open ends of the fuel lines, so no foreign particles can enter.

4.Disconnect electric choke wires if equipped (identify if necessary).

5.Disconnect all linkage and return springs.

6.Remove the 4 hold down nuts and washers (if used).

7.Remove carburetor from intake manifold.

8.Cover intake manifold carburetor flange with a clean rag or towel to prevent any foreign objects from falling into the engine.

Installation of New Carburetor

1.Set old carburetor and new carburetor side-by-side on work bench.

2.Examine linkage connection (throttle cable [rod] and kickdown cable [if applicable]) transfer to new carburetor in same location if possible.

3.Install flange gasket over intake manifold studs on intake manifold, then install your new carburetor. Install throttle cable bracket on driverʼs side rear stud if applicable.

4.Install hold down nuts and washers (if used), tighten in a criss-cross pattern DO NOT TIGHTEN HOLD DOWN NUTS COMPLETELY.

5.Attach throttle linkage then operate from inside the vehicle to be certain there is no interference of throttle plates, throttle linkage, accelerator pump arms or fast idle cam lever.

6.If there is no interference or resistance in throttle operation then you can tighten the hold down nuts to their final torque value, 100 Inch Lbs. (8 Ft. Lbs.). Most intake manifold studs are a fine thread and therefore tightening the hold down nuts must be tightened in a criss cross pattern and in a number of steps before arriving at the final torque value. Rapidly tightening the hold down nuts to the final torque spec or over-tightening will cause performance problems as this process can warp or potentially break the throttle body.

7.Install vacuum hoses. If the PCV was originally attached to the carburetor it should be installed the same way on your new carburetor. Vacuum connections to the new carburetor as shown below:

Timed Spark


Full Manifold

Timed Spark Port

PCV (rear of carburetor)




Distributor vacuum advance may also be connected to the tube in the primary metering block.

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