Mixture – Air and Fuel Filter
Install the injector and the fuel pump onto the engine. If the throttle shows any sign of sticking, loosen all the butterfly screws and tap the shaft back and forth, then all the way to one side. Tap halfway back to center to relocate the line and re tighten the screws. Adjust the butterflies when the engine is warm if possible , except when running methanol, adjust them when the engine is cold. Use thin intake gaskets where possible since thick gaskets may cause the throttles to stick. The butterflies MUST be adjusted EXCATLY the same on both sides of a V8 injection.
STACK INJECTIONS : You should use the rule of thumb that .002 ” is good for engines on Methanol – .004” for all engines on GAS, and .003” for All engines on E-85 .
Hilborn and Enderle Hat( Blower injectors ) Injectors : .008″ butterfly gap for unblown and .010″ for most blown .012″ engines with over 25 lbs boost or over 500 cu in
Use the outside stops to adjust the initial setting, then later you will learn how to set the idle using the barrel valve adjustment, NOT the idle screw stops.
The main mixture control is the jet inside the by-pass container (Primary by pass ) ( Jet Can ), the #4 By-Pass Valve. To change the mixture, unscrew the cap from the container, and change the jet in the cavity in the cap. Increasing the size of the jet leans the mixture. This container also includes a 4-sided poppet valve and a spring. The Spring should have a .020″ dia wire for alcohol unblown .024” for blown engines and a .016″ dia wire for small engines, gasoline, and un blown on E-85 . If the poppet is removed, be sure it is replaced with the pointed end away from the spring and toward the pump. Operating fuel pressures and recommended jet sizes are approximate starting points only. These pressure readings will be attained only at 6000 RPM and with the throttle fully opened. Do not hesitate to use other jet sizes when conditions warrant. You will typically need about 6 jets assuming you got the correct advice about setup. You don’t have to change jets often, but you may change them a few times during the dial in period. Call Mike at 615-457-3192 or e mail Mike@Alkydigger.com for help.
Do not, under any condition, attempt to run the engine without installing a high quality fuel filter. We strongly recommend the screen type filters and advise against using paper, ceramic, or laminated metal filters. HILBORN manufactures several types of screen filters. The filter may be mounted anywhere on the intake side of the pump. In addition to the fuel filter, a safety screen is also incorporated into each of the individual injection nozzles to catch any stray particles of dirt. These screens may be cleaned by removing the nozzles and blowing out any foreign material, however, care should be taken to avoid puncturing the screens. We stock five different kind of filters at Alkydigger from Small #6 Billet filters, to large #12 Canister style. They must have a stainless element, paper is never acceptable.