Quick Fuel Technology 4500 Alcohol Conversion Kit - Manual (Page 3)

between the flat surface of the float and surface directly below. This is the correct dry setting and you
should not have to alter this initial setting a great deal when running. Repeat this process with the
second bowl.
15. Install the jets supplied in the metering blocks; install the power valve plug and gaskets.
16. Install the metering block gasket and fuel bowl gasket on the metering blocks.
17. Install the second fuel bowl gasket on the fuel bowl extension. Note the location of the accelerator
pump discharge hole to be certain the fuel bowl extension is properly oriented.
18. Place the metering block on the main body, install the fuel bowl extension, then install the fuel bowl
(be sure the accelerator pump operating arm is oriented correctly over the fuel bowl pump arm). Install
the blue nylon gaskets over the new, longer fuel bowl screws and insert through the fuel bowl, fuel
bowl extension and metering block. Tighten in sequence and torque to 35 inch pounds.
19. It may be necessary to re-adjust the accelerator pump orientation and over-ride spring adjustment.
With the carburetor inverted, check the alignment of the fuel bowl accelerator pump arm to be sure it is
centered on the adjustment bolt head. If necessary re-align with an adjustable wrench or suitable pliers
that will not mare the finish. Once aligned, check the pump override adjustment. There should be
tension on the fuel bowl pump arm at idle and some clearance at wide-open throttle. The
recommended clearance at wide open is .015”. The clearance does not have to be exact; the primary
reason for this measurement is to prevent the pump arm from bottoming out against the bowl. This
could possibly result in the accelerator pump housing loosening up over time resulting in a fuel leak.
20. Adjust the idle mixture screws to 2 turns from lightly seated as your baseline. You can leave your idle
speed screws in approximately the same position although this would be a good time to be certain that
your primary and secondary idle speed screws are an equal number of turns open. This helps to
balance the carburetor.
21. Install your carburetor on the intake manifold. Run your electric pump for approximately 15 seconds.
If you have a belt or engine driven mechanical pump crank the engine for approximately 15 seconds.
Operate the throttle by hand or have a helper observe that fuel is coming out the accelerator pump (this
may take a couple of strokes to fill the passage). Once you have accelerator pump shot from both the
primary and secondary you can now start the engine.
22. Note in extremely cold air temperatures or if the mixture happens to be too rich, it may be necessary to
“prime” the engine with either gasoline or in some cases carburetor cleaner will work. It does not
require a large volume just enough to give the engine a shot of a more combustible mixture.
23. Once the engine has started allow it to run at a slightly elevated speed to build a little heat in the
engine. This is a good time to check the float level to make sure they are correct. If the carburetor is
flooding or you have to adjust it down a great deal your fuel pressure is too high. The larger needle
and seat (.150” versus the standard .110”) is more difficult to close with elevated fuel pressure. If you
have to adjust the needle and seat assembly down (clockwise) then you are reducing the amount of
float drop. This will ultimately reduce the flow ability of the needle, regardless of pressure. A
properly set float level (the 3/8” dry setting you did earlier on the float bowl) will flow more at 6 P.S.I.
than a larger needle and seat adjusted down only .075” will flow at 9 P.S.I. The higher fuel pressure
will not “force” the needle to flow more. Do not confuse pressure with volume. Just because you have
pressure does automatically mean you have volume. Lower your fuel pressure and concentrate on
volume delivery. Your carburetor will work a whole lot better at low speed and you won’t have to
worry about “running out of fuel” at the top end.
24. Once the float level has been established and the engine has run long enough to build some heat, adjust
the idle mixture screws the same way you would a gasoline engine. It is necessary to find the “lean”
position of the idle mixture screws, the point at which the engine begins to slow down or labor because
it is too lean. If you turn the mixture screws in and the engine speed picks up then the mixture is too
rich. Should all the mixture screws be turned in all the way and the engine speed does not fall off then
it may be necessary to either change the idle feed restriction (reduce the size) or increase the size of the
idle air bleed (larger number). Ultimately you want to have the mixture lean out before the mixture
screw is seated, then back it out approximately ¼ turn. This gives you the best idle air/fuel mixture
setting and quality.
25. You may also want to consider installing a “lean out” valve in your intake manifold. This is simply a
device that induces a vacuum leak. The helps the engine heat up quicker when first started.
26. Once you have the float level and idle mixture settings established you can now make wide open
throttle runs. While there are numerous ways to determine the proper jetting a couple of basic
parameters help establish if you are in the correct range. First, the engine should gain a little heat
going down track, something on the order of 20 to 30 degree engine temperature. Second, you can
change jets using the MPH as a reference. If the MPH picks up you are obviously heading in the right
direction. Conversely if the MPH declines then the last change hurt the performance and probably in
the wrong direction.