Air fuel ratio Ljet Options

[Geezer914]

I am trying to adjust the air fuel ratio on me 2056 Ljet. I read the article that was posted a while back. I adjusted the wiper arm and set the idle at 1100 rpm (Raby 9550 cam) with the idle AFR at 13.2. When I check the high rpm the AFR is at 12.1. If I adjust the high rpm AFR to 13.2, (moving the large wheel 7 teeth CW) the the idle AFR is 16.9 with the mix screw all the way down. If I readjust the wiper arm to 13.2, then the high rpm AFR goes back to 12.2. Can't seem to find a happy medium. I know when you adjust the wiper arm it changes the mixture linear from idle to high rpm. How much more can I adjust the large wheel CW?

[914werke]

If your idle is high and no change when you adjust the air bypass screw on the throttle body, then you have a vacuum leak.

No. that was prior to testing & locating a AAR that would close but still allow air past.
Then started back at square 1.
Valve adjust. Static timed. Checked or reset all sources for vacuum leaks. Set AFM bypass screw to baseline (4.5 turns from closed). TB plate is seating full closed & cracked the idle screw .5 turn. Full charge on battery. Will take a few trys to start but will ..roughly. Fuel pressure is 36-38lbs & reacts to opening the throttle.
Now I have to manually feed throttle to keep it running
EDIT: Timed to the 27BTDC (mark) at 3400, cannot get a reliable idle (800-1k) to time at the 7.5 degree mark seems to run well on throttle but as revs drop stumbles & will not stay lit.

This was a carbureted 2056 originally D-jet so the impeller has marking for both D-Jet & L-Jet (0=TDC, 7.5 & 27 degrees BTDC)

[ClayPerrine]

If your idle is high and no change when you adjust the air bypass screw on the throttle body, then you have a vacuum leak.

No. that was prior to testing & locating a AAR that would close but still allow air past.
Then started back at square 1.
Valve adjust. Static timed. Checked or reset all sources for vacuum leaks. Set AFM bypass screw to baseline (4.5 turns from closed). TB plate is seating full closed & cracked the idle screw .5 turn. Full charge on battery. Will take a few trys to start but will ..roughly. Fuel pressure is 36-38lbs & reacts to opening the throttle.
Now I have to manually feed throttle to keep it running
EDIT: Timed to the 27BTDC (mark) at 3400, cannot get a reliable idle (800-1k) to time at the 7.5 degree mark seems to run well on throttle but as revs drop stumbles & will not stay lit.

This was a carbureted 2056 originally D-jet so the impeller has marking for both D-Jet & L-Jet (0=TDC, 7.5 & 27 degrees BTDC)

L-Jet needs 28-32 PSI. The regulator on L-Jet is not adjustable. Put the proper L-Jet fuel pressure regulator on it and recheck the pressure.

The timing should NOT be set at 27 degrees at 3400 RPM. That is only for D-Jet. L-Jet uses7.5 degrees at 900 RPM. Different distributor so setting it at 3400 RPM will end up with the timing way off.


I have been working on L-Jet for over 35 years. This sounds like a major vacuum leak or false air that someone tried to compensate for by increasing the fuel pressure.

Did you check the oil cap seals? Do the heads have vent tubes? L-Jet didin't use the vent tubes, so they have to be plugged. That will cause false air issues.

Clay