Finally started to tackle the carb rebuild, based on all the great advice found on FChat. The first carb I dismantled has me stumped. I removed the top, and when I tipped the old fuel into a waste jar a small lead plug dropped out. I looked carefully for an open hole and then when I tipped the carb again, a small ball bearing fell out. I stipped the rest of the carb, and then another for comparison, and I can't see any obvious hole in the first carb. Shaking the first carb doesn't rattle like the second. I'm guessing the check valve for the accelerator pump is what fell out, but it's not clear from comparing the two carbs where the plug came out or the ball goes. I have this nasty idea they both go under a brass plug at the top of the float chamber. Anyone run into this?
Chapter 13 (DCNF) of the Haynes Weber Book is available at All Ferraris -- it has some fairly decent cross-section drawings that might help.
I suggest you use a maganet when you are removing bolts from the carburetors. I just started my rebuild a couple of days ago. I removed My first Carb last night, thank you Sledge for helping me out. Anyways, be careful, with the bolts, I notice some have two washers. I am not certain how comfortable you are with the 40 dcnf carbs. I would recommend studying the 40 dcnf diagram, and maybe taking pictures. Hope this helps. I will be posting my rebuild process on fchat. I also plan to do a belt service.
I remember when I drilled and replaced my lead plugs, there was one plug that was different than the rest, and behind that plug was the ball you are talking about. For the life of me, non of my pictures capture it. I would carefully compare all the plugs on the two carb, and find the one that is missing. I will keep searching in the meantime.
I think that ball resides behind the larger of the plugs with the red arrows. are all three plugs in place as marked by the red arrows? Image Unavailable, Please Login
Thanks Geno. Yes they are all in place, but I think you are right, the ball goes behind the larger brass "plug". Did you drill that out? I thought it was a long calibrated bush for the accel pump. Thanks to the rest of the folks on the thread too, Im reviewing the Haynes manual now. The diagrams may be schematic and not show where the smaller lead plug came from. I've looked at the two carbs and I can't see an "open hole" in the bad carb. I'll keep looking. The lead plug could also be completely unrelated and a left-over from a previous rebuild, etc. This may be a job for Pierce Manifolds...any thoughts? Thanks, Gregg
First: All hail Pierce Manifolds! Second: Geno, thanks for trying to chase it down. That plug is in place...but I was looking in the wrong place. Despite Steve's suggestion to look at the diagram, I missed that there are two ball check valves. The one that came loose is in the red circle, it lives inside the banjo bolt for the accellerator squirters. Mike at Pierce Manifolds pointed me to the possibility that the lead plug for that banjo bolt came loose, follwed by the ball. Sure enough you can see what it looks like open (left side) and how it should look (on the right.) Thanks to all. I'll keep going, I think I'm going to change the jetting from 55/130/220 to 52/140/200, but first I'll finish rebuilding them with the original jets and work to get them balanced. I also discovered that the butterfly's were only open about 75% with the pedal to the floor--so I'm hoping for a real change! Thanks again, Gregg Image Unavailable, Please Login Image Unavailable, Please Login
