Fuel Injection choke adjustment for 63

[Michael G.]

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According to the 63 shop manual, the fuel injection choke cover should be adjusted 3 notches lean. Can anyone explain what that means? 3 notches from where? The cover only shows direction of lean and rich, not location. The picture is how mine is set now.

[David M.]

Find the neutral choke valve (butterfly) position when its cold. So vertical. Adjust it to close down cold. Start it and adjust the pull off gap. Hows it start and run? If its too rich back off one notch at a time. Too lean do the opposite.

The book takes into account a fresh bi-metal spring. The spring looses tinsel as it ages and needs to be adjusted accordingly as it ages.

The book is a ball park. Each engine needs to be adjusted for its own optimal operation. Carburetor chokes generally indicate neutral rich lean as you can see this isnt the case with FI

[Jim L.]

David has given you practical advise. My procedure for adjusting cold enrichment on ALL FI units is substantially similar.

Regardless of what the shop manuals say, I adjust the cold enrichment cover such that the mechanism will reliably turn on when the engine is cold. I then evaluate how long cold enrichment will remain on after the engine starts. If it remains on for much more than a couple of minutes, I'll rotate the cover slightly in the "LEAN" direction and evaluate the result when the engine is again cold. I'm seeking the sweet spot which produces reliable turn on and relatively rapid turn off.

[Michael G.]

Find the neutral choke valve (butterfly) position when its cold. So vertical. Adjust it to close down cold. Start it and adjust the pull off gap. Hows it start and run? If its too rich back off one notch at a time. Too lean do the opposite.

The book takes into account a fresh bi-metal spring. The spring looses tinsel as it ages and needs to be adjusted accordingly as it ages.

The book is a ball park. Each engine needs to be adjusted for its own optimal operation. Carburetor chokes generally indicate neutral rich lean as you can see this isnt the case with FI

Thanks David, I'll give it a try. BTW I also have a Targa Blue 72 big block. Looks like the pic in your profile.

[Michael G.]

David has given you practical advise. My procedure for adjusting cold enrichment on ALL FI units is substantially similar.

Regardless of what the shop manuals say, I adjust the cold enrichment cover such that the mechanism will reliably turn on when the engine is cold. I then evaluate how long cold enrichment will remain on after the engine starts. If it remains on for much more than a couple of minutes, I'll rotate the cover slightly in the "LEAN" direction and evaluate the result when the engine is again cold. I'm seeking the sweet spot which produces reliable turn on and relatively rapid turn off.

Thanks Jim, Makes sense. I'll give it a try.

[David M.]

Mike,
Its an April built 1968 roadster, non original color. Originally a 978 International Blue exterior.

Jim,
There is a bi-metal spring behind that cover right, that's acting on the choke valve?
The hot air tube needs to be loosened while the adjustments made.The filter intake hose can/should be removed so you can visually observe the butterfly's' position both cold and at operational temp or fully open.
Tx
Dave

[Dan H.]

I had problems with my choke not coming off the fast idle setting, turned out to be a faulty seal on ther hot air tube, it is a must to get the tube sealed for proper choke operation.
Dan

[Jim L.]

Mike,
Its an April built 1968 roadster, non original color. Originally a 978 International Blue exterior.

Jim,
There is a bi-metal spring behind that cover right, that's acting on the choke valve?
The hot air tube needs to be loosened while the adjustments made.The filter intake hose can/should be removed so you can visually observe the butterfly's' position both cold and at operational temp or fully open.
Tx
Dave

Dave, yes there is a bi-metal spring which causes the choke plate to open and close.

Thanks for mentioning the hot air tube. Use a 1/2" wrench to loosen the tube nut prior to adjusting choke turn-on or on-time.

There is no need to remove the air cleaner adapter prior to making choke adjustments. Between the choke housing and the ring for the Venturi cone, there is a slender roll pin pressed into the choke shaft. It points toward the plenum. You can observe this pin as the choke shaft rotates in lieu of watching the choke plate.

Jim

[David M.]

Copy that Jim tx. Forgot about the roll pin. Been many years since Ive had my hands on a later FI.