67 L36 Carb rebuild question

[Lawrence S.]

I rebuilt my carb on my 67 L-36, and it seems to run ok, but I have to run the passenger side Air Fuel screw all the way in to get a good idle. The driver side AF screw is out 1.5 turns from seat. I know both screws should be off the seat about 1.5 turns. Do I have some internal gas leak to cause this problem? Something is not right?

Any thoughts?

Thanks

Lawrence

[Timothy B.]

Re: 67 L36 Carb rebuild question

Lawrence,

There is a internal fuel leak somewhere inside, it could be caused by non flat surfaces and fuel is getting by the gaskets. Double check and make sure the passenger side air bleed is not clogged with something first, that could cause a very rich mixture.

[David H.]

Re: 67 L36 Carb rebuild question

What cam/mods does your engine have? In particular, is your idle speed screw set low enough to have throttle plates exposing idle transfer slot. See link below, second FAQ from bottom.

https://www.holley.com/support/faq/

Experience any strong backfires that could have ruptured power valve. One quick power valve check: screw BOTH idle mixture screws all the way in. If engine continues to run then power valve is a likely fault. see link below at about 2:40

https://www.youtube.com/watch?v=mE_xTUXQJQ8

Dave

[Lawrence S.]

Re: 67 L36 Carb rebuild question

What cam/mods does your engine have? In particular, is your idle speed screw set low enough to have throttle plates exposing idle transfer slot. See link below, second FAQ from bottom.

https://www.holley.com/support/faq/

Experience any strong backfires that could have ruptured power valve. One quick power valve check: screw BOTH idle mixture screws all the way in. If engine continues to run then power valve is a likely fault. see link below at about 2:40

https://www.youtube.com/watch?v=mE_xTUXQJQ8

Dave

I seated the AF screws and the cars dies so the pv is probably ok, but I need to check the vacuum and confirm the correct pv is in the carb. I reused the old pv, and have a new 6.5.

Thanks for the links they are great!

[Danny P.]

Re: 67 L36 Carb rebuild question

May have the wrong meter plate gasket check for proper gasket and check meter plate for warpage use a aluminum file for any high spots that would cause internal leaks

[Lawrence S.]

Re: 67 L36 Carb rebuild question

It dawned on me that I had to reuse the old metering plate gasket because the one in the kit was not 100% correct. I narrowed the leak to a slow weep between the base plate the carb body at the secondary. Danny I suspect you are right. I have a bad metering plate gasket. I have a correct one coming. The difference between the correct one and the one in the kit are two small holes below the top center rectangular opening in the gasket. These little holes are for the small air bleed passages.

[Danny P.]

Re: 67 L36 Carb rebuild question

It dawned on me that I had to reuse the old metering plate gasket because the one in the kit was not 100% correct. I narrowed the leak to a slow weep between the base plate the carb body at the secondary. Danny I suspect you are right. I have a bad metering plate gasket. I have a correct one coming. The difference between the correct one and the one in the kit are two small holes below the top center rectangular opening in the gasket. These little holes are for the small air bleed passages.

It good to use the Holley kit from Holley ,it the best way to go hope it all works out for you ,

[Lawrence S.]

Re: 67 L36 Carb rebuild question

The secondary metering plate gasket that was in my carb had two extra holes as compared to the gasket that was in the kit. As it turned out the two extra holes were not needed so the gasket in the kit worked fine. I replaced and the carb works great.