Hey Fellas,
I picked up a 351C-4v / FMX Eliminator back in June with the intent of cleaning it up, sorting it out, and reselling it over the summer. Summer is nearly over and I’m still trying to resolve a few issues. Fix two things and one more crops up, but at least the list is getting shorter.
When I first picked it up it ran fine. Over the summer it has been slowly degrading, and now it will intermittantly stall when I put it in either drive or reverse. So far it has always started right up fairly easily. Once it is warmed up it doesn’t like to sit still in traffic, and now sputters coming off idle.
I was going through the basics this weekend;
Carburetor = Edelbrock 1406 (600cfm)
Idle is high ~ about 800-1000rpm. If I dial it down it bogs and dies.
Timing = 6deg btdc at the above rpm, with no vaccuum advance. Reving causes the timing to track upward over 20deg, as expected.
I put a vacuum guage on it: 8" vacuum at idle. Horribly low. blip the throttle and it drops to zero and then jumps to about 15", before settling back to 8".
It has a dual vacuum advance unit, with the distributor side being bad (leaks). I thought that was likely my culprit, being a vacuum leak, but even capping it off did not improve things at all. Have a new unit on order now, but I don’t think this is the root cause.
I’ve capped the ports on the carb as well as removed and capped the connection to the vacuum tree, but no change in vacuum.
I did a cursory leak check with carb cleaner around the base of the carb but the engine was hot so I didn’t want to get to aggressive with flamable sprays. I plan to break out the propane torch tonight and see what I can find.
Another item to note is that the car bogs way down and threatens to stall when I make a sharp left turn around a corner. I thought it might be the float level in the Edelbrock (a PITA to adjust), but some further research indicates that it may be an internal manifold gasket leak causing a bog when oil moves over the leak, throwing off the air/fuel ratio.
No apparent coolant loss. No apparent coolant in the oil, or vice versa.
Is it possible that I simply have the carb adjusted so far out of whack that I’ve induced this issue myself? I tried to follow the Edelbrock instructions, but at this point the main idle seems to be open too far to actually see any effect from the mixture screws. I’ve tried to find something online that says what the “baseline” adjustments would be for the mix screws and main idle screw (y’know, like Holley has), but I’m not finding squat to “zero out” the carb and start from scratch.
So… I’m interested to hear some other possibilities. Thanks in advance!