Big RPM drop with stelling /helling

[KobraKarl]

HHMMMMMMMMMMMMMMPH ..........I think your crystal ball has been dropped !..............hard !

I can tell you , I stripped those babies down to the last little nit,

All parts were tanked in fresh cleaner for 36 hrs

then washed in near boiling high detergent water ,

every hole, port, nook and cranny was bown out with 120 psi.
fine tip nozzle,

then rinsed twice more in near boiling water and blown out again,

reassembled them with all new Holley parts and gaskets with the "Holley Rebuild "book open in front of me,

every thing assembled with a dab of vaseline where needed,

torqed every screw to the list inch pounds


Man i tell ya . if thse two carbs arent "right " now ,I could rebuild them another six times and I wouldnt know what to do different

And .....they run great!

I'm going to do some filter swapping later today and see how things work out .....

[SCOBRAC]

The filters are not the problem.. a more restrictive filter (which Hellings are not) would slow your idle down.. Did you straighten the carb bodies with a straight edge?? What were the tolerances used?

HMMMMMMMMmmmm??? Also when you reassembled them did you do it in the same way you took them apart, keeping track of which body and jet plates went with each body. If you didn't and you also didn't true the housings, bodies and jet plates you likely have a vacuum leak at the carb.. It isn't a good idea to use compressed air on a carb without filtering first..

What lash did you set at the accelerator pump housing? You should have a few thousands to 15 thousanths gap. Did you change the primary set screw setting? (accessable from under the carb) If no, were you keeping track that you reinstalled the primary plate and the secondary in their respective positions?? If yes, how much did you open or close the primarys?

All of the items listed can cause the problem you describe..

Good luck..

[KobraKarl]

Micheal , thanks for the check list.........
both carbs had warped bodies which i trued carefully with a fine tooth file , I marked primary and secondary components lightly with an awl, I also rebuilt the two carbs in sequence to avoid any confusion,my shop compressor does have an inline filter, I did not touch the secondary set screw, I just went down and took a look,the vac. secondary apears to be open maybe a "curly red one",primary's are linkage adjusted.

Now if i didnt make this very clear, it went like this; after everything was bolted back up (exept cleaners) I started it up and played with the floats,idle screws,and linkage until she was running pretty nice. Went for a 10 mile shake down and she ran well. 3 or 4 days later the S&H come in the mail ,i bolt them on and the rpm's wont come down when she is warm............ so i just turn down the primary idle screw and again she runs fine.

I just couldnt understand the "apparent"correlation. After all this feed back I'm starting to wonder if maybe the idle cam stuck or the distributor stuck or some other "coincidental" condition.
I was going to experiment today , but went to the seattle roadster show instead..............several FFR an SPF and one original 289 in FIA format.

[Mr.Fixit]

Originally posted by southernfriedcj


Driving a car without an airfilter would seem to be a good way to invite an engine fire. If you have backfire through the carb(s), you better be fast with the fire extinguisher! I've never put a burning Cobra out, but I put several hundred car fires out in my time on the Atlanta Fire Dept.

If you catch your carb on fire, before you spray it with the extinguisher, crank the motor over with the starter, it will suck the fire out. If the motor is running, rev it a good one. I have never had a "top of the carb" fire, that could survive at RPM. The accel pumps will feed it for a monment, but then it will get sucked through.

[SCOBRAC]

I told you it was haunted.