There is a post a couple of pages back about an LS5 with a Rochester carb that was hard to start. I have a 71 LT1 with original Holley that is acting exactly the same.
I have to crank it 6-7 times with lots of gas pedal jiggle to get it to cold start. When it finally fires, it runs rough for a few seconds, then it runs fine and it will start immediatly for the rest of the day.
If I slowly depress the accelerator one time and release(as per owners manual) the butterfly remains open about half an inch.
About ready to take it to the shop.

Thanks for any suggetions
Neil

my car does the same thing if it sits for a week or two, float bowls go dry, but the next day two pedal pumps and 3 or 4 starter revs and it fires, does you car sit alot?

My '69 427/435 acts the same. I figure it's either the choke or possibly float levels, but it's not a real problem either. I think these hi-po engines are by nature cranky and finicky due to their higher compression and more radical cam profiles...like a thoroughbred horse, they simply require more attention to maintain their level of performance.

I tend to accept it as simply part of their nature.

Ive seen it often be a symtpom of fuel seepage...

the carb will leak quite a bit of fuel into the intake..

this will just pool up...

flooding it after it has sit for a while..

for me this only seemed to be an issue if the car sat cool..

ie in the garage.. (probably due to contraction opening a seal) try to hold the pedal to the floor (with just the one pump to get it floored) ... see if it starts that way...

may need a carb rebuild.
im betting its seepage.

|UPDATED|9/13/2004 2:01:18 PM (AZT)|/UPDATED|

I'll agree with Gunslinger that the Hi-po engines are a bit cranky but I don't think that is the reason for the hard starting. I just put a new Holley on mine last year and now I'm worried that the oil pump has no chance to prime the system because it fires so quickly!! I think it's pretty relevant to your situation since I'm still running 11:1 compression, solid lifters, and a cam with higher lift and longer duration than the stock LT-1 cam and never any problems starting.

Just another 2 cents, my experience with the last 1/2 dozen Holley's on a variety of cars has taught me one thing, there is nothing like a new one. You would think that they rebuild well but my experience has been that they never quite perform 100% no matter how careful the rebuilder is. Maybe I haven't meet the right guru yet but the guys I've had in the past were supposed to be some of the best and I always ended up unsatisfied. My advice, shelve the original and buy a new one (and not the ridiculous 870cfm GM put on the LT-1) so it will perform for the the street.

Good luck!!

Rick, I have to disagree. Sort of.
A good rebuild by a good rebuilder with a good core can be and is as good as new.
Some rebuilders miss thing like wear in the throttle shaft. Then it's close, but not quite right.
I try hard to avoid rebuilt out of the box, I usually need to readjust everything before I can be happy with it, so I just rebuild the old one myself.
I agree it's tough for many people to find the right rebuilder.

Not sure, because I never took the time to search it out but, I believe the 70 came with the L-88 Holley, the 71-72 came with the 750 cfm Holley, 71 was R4801A (3989021) now if you want to keep the #'s matching these carbs are hard to find and if you do find one they go for about $500. and more, you might have to rebuild the original Holley, if someone has not butchered the original it should work out OK

|UPDATED|9/15/2004 10:07:35 AM (AZT)|/UPDATED|

Hope everyone doesn't mind if I chime in. I agree with Ken. I can speak from experience that most people that have trouble with their holley's is because they were rebuilt correctly.

Holley specifically invented the Modular 4-bbl that we know today as a classic holley back in 1957 for the Ford T-bird. They went to this design for many reasons one of those being they were easier to assemble, dissassemble and could be rebuilt.

Most people fail to check the straightness of the sealing surfaces and for throttle shaft wear. One of the best things you can do with a holley is to make sure the sealing surfaces are flat. If they're not, then you can use a standard metal file to make them true.

I've also been to enough events,racing, cruise ins and road tours to know that most people don't really know how to rebuild a carb correctly. Most just think its taking it appart, adding new gaskets and putting it back together. Thats where most get into trouble.

The other bad rep that Holley carbs get are from Swap meets. I talk to dozens of people every year that come up with a question about a carb they bought off a buddy, off the internet or at a swap meet. First off everyone of these Holley carbs can be rebuilt. The problem lies in knowing what was done to it before you purchased it. A lot of these carbs have been rebuilt countless times, and many of them have probably had modifications done to the airbleeds or metering block. While those mods can be fixed you have to have the right parts and the know-how. Most of those replacement type parts are only available through professionals as it takes special tools to remove them and install new ones.

One thing I can recommend is if you have an original Holley then send it to Holley's custom shop. They will rebuild it to its factory specs, fix or replace any broken parts, or in certain cases fabricate a replacement piece. It only makes sense to have the company that made the darn thing bring it back to its glory. I have seen carburetors that looked like they had been sitting at the bottom of the ocean for 30 years look like they rolled out of the factory brand new.