Interesting, you really don't have enough cam/motor to need the plate holes, surprised that was even suggested.

Does it break up at 3000rpm like it used to at 2300rpm or is it running clean all the way up??

Glad it is working!

 

I agree with Putt, the hole thing means there is too much air flow required at idle that the throttle plates have to be to far open and you just plain don't have enough motor or idle speed for the problem to be there. There are only three ways to have vacuum at the ported vacuum port at idle is for the throttle plates to be to far open at idle or a crack in the carb body or a bad gasket (this is unlikely but always a possibility).

 

No it pulls up to 3000 now, however If i hold it at oh say 2500 i get this lite surging, can feel it more than hear it. but seem to run fine.
Im going to tear the Holly completly down and see if i can find anything. I noticed it leaking, I had it setting on a box after I removed it. float level was correct and I had rplaced both blue gaskets, so eather I have a leak in the base gasket or a crack somewhere, also looking at the feed hole for coming off the metering block from the pw valve ( the one cast into the main body ) doesnt seem very big only about the size of a 80 or 81 main jet. Is this right ? Seems small For a Power valve passage.

 

jav-there is no fuel passage in the main body for the power valve fuel. It joins into the main well(behind the main jets) thru two PVCR(power valve channel restriction) in the metering block, visible when the power valve is removed. The two PVCR's are equivalent to about 6-8 jet sizes and measure about .060" diameter each.

I think you might be looking at the accelerator pump passage. Is it in the middle of the main body, in a kind of recess?

 

jav-what is the Holley list number for that 500 cfm 2 barrel??

 

The power valve dumps additional fuel into the main metering passages which dumps the fuel into the air stream thru the booster venturis. Your surge problem sounds like a lean condition, try running a high float setting (usually helps). If that doesn't help try lowering the level. Raising the float level enrichens the mixture and lowering leans it out.

 

Putt, the numbers in the Holly 500 are
Main body 6R 3250 B 3D
Base 3975A
Metering Block 5925

Bear, thanks, ill try that this weekend, it ( 2100 )does seem a tad lean, I do have to back the Idle needles out several turns to smooth idle. Any Idea How much in inches like 1/8 or so I would need to change the float level ?
Getting oh so much closer.

 

jav, those are the casting numbers for those pieces, I was referring to the list # on the front of the choke air horn. Sorry, I should have specified what numbers!!

Try changing the float level in 1/32" increments, it does not take a large change to be noticeable. The carb kit likely had a cardboard gauge for setting the float, if it did not I use the appropriate size drill bit or a dial caliper(can't remember how the 2100 sets the float!!!CRS disease!!).

 

I agree with Putt. It doesn't take much to change the mixture and small is better because you can go right by the right setting and be into the same simptons, only it's now too rich.

 

Putt the numbers are
4412-3
1324

I wish I could make it run, I realy liked the throttle responce. but never could find that majic combination of jets and power valve. oh and as a sideline, i dont have any Carb Iceing problems with the 2100 like I did with the Holley.
I sure Thanks you folks for all the help.

 

jav-here are the correct Holley part numbers for your carb:
Renew kit:37-474
Trick kit(more tuning parts, but muuuch more $$$):37-933
Main jets:122-73(number 73 jet)
Power valve:125-50(opens at 5.0 in. hg.)
Accelerator pump shooter:Straight type(no tube)121-128, Tube type-121-28
Just curious-do you have the part numbers of the bowl and metering block gaskets you installed??

 

Putt ,I have to tell you I tried the 73 main jets and 5.0 Powervalve and my plugs after a couple of days were black. As close as i ever got was a 6.5 power valve and 69 jets, however the plugs still had a bit of black at the base and white on the tips, At 67 jets the black dissapeared but the whole plug was white, but it ran great. It came with a 50cc pump, but I had removed it and replaced with a 30cc pump on Bear's recomendation. I didnt do any thing to the pump Shooter.
oh,the gaskets were pt# 108-83 and 108-91


Raised the Float level on the 2100 tonight will see how it runs tomorrow.

 

jav- The gaskets were a part of your problem at least. The bowl gasket is correct, but the metering block gasket IS NOT. It should be a 108-89, the difference is the type of accelerator pump passage and they are NOT interchangeable. It would have caused an internal fuel leak and the accelerator pump to not function. It would have caused a rich idle and then likely a poor off idle transition, with erratic running since the pump would not work and the fuel leak.

 

Ok I raised the float level and it did richen up , now under light load on a flat road the ox meter bumbes between 450 and 550 milivolts ( whish is prety durn cloas to stoch for a carb )and under hard acceleration goes to over 900 which indacates rich like it should. My next question is about the pertronics.
Do points change as rpm goes up and if so is this part of the advance system.
i knwo the pertronics doesnt change Dwel it just makes spark, wouldnt this change the way the engine runs in the higher RPM's ? And does a duraspark system act more like points ?

 

Points change some in dwell (which in turn change timing) as RPM increases because they are mechanical and physically move. It is not part of the advance system, just a drawback of a mechanical system of making spark. All electronic system do not change dwell, as their dwell is controlled electronically and is constant, even if they are points controlled. In that case the points start the spark, but the duration (dwell) is a function of the electronics. Advance is handled 2 ways. Mechnical advance is controlled by weights and springs and vacuum advance is controlled by a vacuum source from the ported vacuum port on the carburator. And as long as there is enough spark to ignites the fuel/air mixture at the right time, then no electronics will not change anything. Points/coil systems actually produce less spark as RPM increases, where the electronics are constant. Magnetos produce more spark the faster they are spun. Electronics is more reliabile as they don't wear out parts which change the spark dwell and in turn timing.