Holley carb help. fuel dumps after off
 

Ok i have a brand new holley 4160 carb. I jsut got the car running again after everything I've been doing. I noticed the fuel keeps dumping into the intake even after the engine is off.

It runs, but rough and I get pops back through the carb once and a while too. (most when i stomp it).

I checked the timing its close for now. But i think the problem is more the carb.

If it's a new Holley out of the box, you need to disassemble it and clean it before you install it: The new Holley and BG carbs have so much crap in them from the factory that they're seldom usable out of the box. There is garbage in the bowls, and crap in the needle/seat assemblies. Also, the float levels are very seldom set up right, and the overall setup on the carb is very poor. Tear the carb down, clean it up, blow it out, and set it up correctly. You can use my Holley and BG setup papers as a guide to get it right.

Lars

man that sucks, ok well thats next. I did however notice that my fuel lines are very hot. Maybe it is fuel boil. I know rubber line is not a good idea but what is a good alternative other than having to bend metal lines?

Unless you're running an electric pump it wont be the needle seats.

Engine off = no fuel pressure at the needle seat.

It's also unlikely to be float level as the carb would be flooding while running, not when it's turned off.

Your own theory is most likely, that it's fuel boil from heat soak. You may need to fit an insulator or set of cooling gaskets.

Listen to Lars. Every new Holley I have used in the last 5 years has needed to be disassembled, cleaned and set up properly. You'll never get it running to its full potential if you don't know what your baseline settings are.

So how difficult is this going to be to strip it down? I've never rebuilt a carb. Would " crud " in the carb really make the secondaries drip fuel after? If so whats the cause? Floats?

Hey Lars, where do I find your Holley set up papers. I have a 4175 on a 396 & I could use your expertise. I have all your Q-jet stuff but have'nt seen anything on holleys

Before you tear down a brand new carb, check the accelerator pump arm (or arms if it's a double pumper)adjustment. If the pump arms are set too tight, you will have fuel dripping into the carb after the engine is shut down. Adjust the arms(actually the spring under the arm) so there is just about zero clearance. If there's too much clearance, you'll have a bog or flat spot. If too tight, you'll have the fuel dripping into the carb.

You don't need to do a complete teardown of the carb. Remove the carb from the engine and pull off the front and rear bowls and metering blocks. Remove the needle/seats from the bowls. Blow everything out really well, and blow through all the passages. Blow out the needle/seats really well. Not all new carbs are contaminated, but I do see a lot that are - cleaning it up well is a good precaution. Do a careful re-assembly - it's a good idea to lube your threaded fasteners and to spray down the gaskets with some WD or PAM so they won't stick.

Yes, a small piece of dust or crap in the needle/seat will cause the secondaries to drip after shutdown. You can test to see if the bowl is continuing to fill after shutdown by pulling out the sight plug after shutdown and see if fuel dribbles out the hole for a while (put a rag under it). If it does, it means the needle/seat either is not sealing, the float level is too high, or you have a porous casting (I've seen 2 of them).


You just drop me an e-mail request for the Holley or BG papers and I send them to you. I also have a complete listing of all tech papers available by e-mail request to:

V8FastCars@msn.com

Lars

I bought a Holly from Summit, thought it was the right one, and as mentioned above it never ran right, flooded, etc. After several months of driving I ended up taking it apart. I found silicone in the timed vacuumed port, and in the bowls. Installed a carb rebuild kit and it's better but still tempermental. I called Holley repeatedly and never got to talk to a tech, nor receive any return calls. I'll never buy another.

These are comon issues with new aftermarket carbs, regardless of brand (Holley, BG and Edelbrock all have some quality and consistency issues). They're mass produced, and they often have some funny things going on with them.. It's why I call this the 50% hobby: Only about 50% of the parts you buy will ever work correctly, fit right, or operate as advertised. Consider any part you buy, including carbs, to simply be a good starting point to do some work. Tear it apart, check it, set it up the way you would build it yourself, and then enjoy your car. I have a "new carb setup" service for Holley and BG carbs, and it's surprising how many carbs I get drop-shipped to me from Summit and Jeg's for checkout and verification before sending the parts on to their owners. It's also shocking how many bizzare issues I've seen with the new carbs (regardless of brand), so the problems mentioned in this thread are not at all uncommon (not that this observation helps your carb situation).

Lars