BG holley carb.

[blue69runner]

Now that the car is on the road finding out it is running too lean. Pulled out the primary jet's and they where 76 jet's. Changed to 80 jet's and a new metering plate for the secondary with 081 to .040. Do you think that is enough fuel for my 383 400 hp motor. This Ethanol fuel suck's. Running 93 pumped gas right now. Got a vacuum gage to day and rest the carb and timing on the motor. Some better but act's like it need's more fuel will pull the spark plugs and see what they look like. Where to white so too lean for sure. Don't want to mess up this rebuilt motor. Have 9.8 too 1 compression. Any thought's would be grate. Just did not want a double pumper thought that would be a bit much for this motor. My carb is single feed and close as we can get it is a 4150 Holley.

 

[Aron Gleason]

Going up in jets isn't the way to go in most situations. Idle and cruise are calibrated by the idle air bleeds. And the Hi speed bleeds come into play the higher the rpms. I would look at air bleeds. And get a afr gauge.

 

[HEMI-ITIS]

Without an AFR gauge or data logger your doing too much carb testing thst will make you crazy!!

 

[blue69runner]

Thanks for the info. But you know if the plugs are not tan and are white then my fuel mixture is way too lean. Have had to put larger jet's in carb's before when reading the plug's this way. Let me try the new metering plate and will let you guy's know what I find out. Thanks again. Blue.

 

[beanhead]

Not necessarily true anymore with today's ethanol and oxygenated peepee fuels,
We did 5 nice clean-cut runs on a new set of plugs in a buddy's 427 fordy. And his stuff is very well-tuned.. Plugs looked damn near brand new all the way to the bottom of the insulators. We did get timing marks on the straps, some heat range coloring on the threads and about a 3/4 turn of color on the flat edge of the shell.
No problem adding a little fuel and seeing how it responds though, you won't hurt anything that way. If seat-of-the-pants picks up you'll know you're on the right track.
I don't consider mine overly lean unless there's surging/bucking at cruise or hesitating under load...or it just feels 'flat', and gets noticeably crisper with more fuel.
Running plugs on the hotter side will keep the insulators cleaner as well.

 

[Photon440]

Now that the car is on the road finding out it is running too lean. Pulled out the primary jet's and they where 76 jet's. Changed to 80 jet's and a new metering plate for the secondary with 081 to .040. Do you think that is enough fuel for my 383 400 hp motor. This Ethanol fuel suck's. Running 93 pumped gas right now. Got a vacuum gage to day and rest the carb and timing on the motor. Some better but act's like it need's more fuel will pull the spark plugs and see what they look like. Where to white so too lean for sure. Don't want to mess up this rebuilt motor. Have 9.8 too 1 compression. Any thought's would be grate. Just did not want a double pumper thought that would be a bit much for this motor. My carb is single feed and close as we can get it is a 4150 Holley.

4150 is generally dual feed, if yours is single feed it could be a 4160.

 

[blue69runner]

Not necessarily true anymore with today's ethanol and oxygenated peepee fuels,
We did 5 nice clean-cut runs on a new set of plugs in a buddy's 427 fordy. And his stuff is very well-tuned.. Plugs looked damn near brand new all the way to the bottom of the insulators. We did get timing marks on the straps, some heat range coloring on the threads and about a 3/4 turn of color on the flat edge of the shell.
No problem adding a little fuel and seeing how it responds though, you won't hurt anything that way. If seat-of-the-pants picks up you'll know you're on the right track.
I don't consider mine overly lean unless there's surging/bucking at cruise or hesitating under load...or it just feels 'flat', and gets noticeably crisper with more fuel.
Running plugs on the hotter side will keep the insulators cleaner as well.

Thanks. It is pointing to not enough fuel. After seeing a seen from orange county choppers when they built and E85 fueled bike. The carb had to have twice the size jet's for the motor to run proper. That suck in my brain file even though it is getting harder to remember every thing now day. It dose take twice as much ethanol to do what regular fuel use to do.

 

[blue69runner]

4150 is generally dual feed, if yours is single feed it could be a 4160.

Well Holley seems to think the same thing but it is an older BG Demon carb. No serial number's on it to refer to. Vacuum secondary. Just doing one thing at a time on it so I will know if that changes it in any way. Have a vacuum reading and going to check the power valve next and see if the number are for that range if the jetting dose not make it better. Thanks