Need help with 225 holly390 never ran right!

I had the same problem with my 450 truck avenger. It bogged bad if I stabbed the gas. I sent it back to Holley because they assured me it would be "fine" right out of the box. It wasn't and I wasn't to thrilled with it. They flowed it, sent it back to me and ask me to bolt it back on and try it. It still bogs a little off idle if I stab it hard but it is MUCH better. I have to give them some credit because it really runs great up and down hills. The Carter I used to run would die coming down a steep hill and got absolutely terrible milage. For what I spent on the TA it still irritates me that it bogs but for the most part I like it.

 

Ding ding ding. Answer was: too plenty.

Mounted a fuel pressure regulator today. Not sure why this has developed over time, but the fuel psi was definitely the problem. I'm wondering if maybe constant pressure on the needle has worn out the spring making it open easily and pressurzie the fuel bowl. Anyway, instantly smoothed out the entire RPM range. Now that I've reduced fuel, I'm getting a lean pop when I stab the throttle, though; time to play with pump cams.

 

Check your timing and timing advance (both mechanical and vacuum) as well. I had a 327 that did that because the distributor weights got sluggish due to it sitting too long. They sort of rusted to the distributor and the lube turned hard. Removing and cleaning the weights as well as applying a thin lube to the pivots cured the problem.
The advice of different weights and recurving the distributor is something to be aware of also.

With a timing light you can plug the vacuum advance and check to see if the mechanical advance is working. Then once you have confirmed that you can reconnect the vacuum line and make a mental note if you are seeing more or more rapid advance.

Good luck - a 3B with a 225 - cool.

 

If it isn't a newer 390, when the engine backfired it may have blown out the power valve altogether. You can't make em' run right w/o the power valve operational. The new ones have backfire protection for the valve.

 

Yeah, this has been a great carb. There was a learning curve to it because of the cid involved, but once over that, what a pleasure to own and operate.

My accel pump lean pop actually turned out to be mixture screws. Back up and running now.