Hi, I just bought some replacement needle valves from So-Cal in Las Vegas. I was suffering flooding secondaries again on the Holley. The one I showed the guy was a .095 but now I have replaced one, I see that he sold me .110's. I am now back at home in the UK and I just took the truck out and the tickover was so slow I had to stop and wind it up a bit to stop her dying at junctions(700r4). She is also a lot slower to start up. Could this be due to the oversized needle valve which has only been replaced on the secondary side or could it be due to a slight float height change? These are the only things that could have changed as she used to start straight away, hot or cold before. All replies greatly appreciated.
first thing to do after replacing the valve, is to adjust the float level. If you have not done that, then that would be the place to start.
Thank you Jim. I did set it with a vernier so I had the same amount of valve protruding from the top of the float bowl.
Even if you have what you believe is a stock pump I would check the pressure just to be sure. I'm sure you could adapt a pressure gauge to your fuel line on a temporary basis without going to the expense of purchasing a regulator and dedicated gauge you may not need. Keep in mind that the new .110 needle and seat you just installed will be less tolerant of 6-7 PSI than your old .095. For setting the float on a carburetor that has no sight glass on the side of the bowl follow these instructions http://documents.holley.com/techlibrary_adjusting_your_carburetor.pdf for " dry setting" a float when rebuilding a Holley. In view of the fact you had trouble with your old .095 n/s I suspect your problem is probably a high float level, can you try running the engine and peering into the throttle bores to see if fuel droplets are coming out the venturi boosters at idle? If that is the case it can be either a high float, high fuel pressure or bad needle and seat.
so...it has a plug, with a slot, that you can remove, and check the float level when it's running? like this? you remove the plug, and fuel should just barely dribble out of the hole, when the engine is idling (ticking over). Adjust the float level up or down if needed.
That is not the proper way to set the float adjustment. You need to do it thusly: 10 FUEL LEVEL The float(s) controls the fuel delivery, however if the float(s) are not properly adjusted a fuel starvation or a flooding affect could result. This operation is difficult to do accurately on a rough-idling vehicle. 1. Mechanical fuel pump, remove coil wire and crank engine over for 10 seconds to allow fuel bowls to fill. This procedure can prevent a power valve blow out. Reconnect coil wire when finished. Electric fuel pumps, let the fuel bowls fill in stages by turning the ignition on and then off, let fuel pump run for a few seconds at a time. This procedure can prevent the needle from being forced up at an angle not allowing the needle to seat properly. 2. Remove the sight plug from the fuel bowl and start the vehicle. 3. Loosen the lock screw at the top of the assembly. 4. Turn the adjusting nut while holding the screw in place until the fuel level is at the bottom of the sight plug hole even with the threads. A slight trickle can be seen at the threads. Turn the adjusting nut clockwise to lower the fuel level and counter-clockwise to raise the fuel level. 5. Tighten the lock screw while holding the adjustment nut. 6. Replace the sight plug and finger tighten. 7. Flush the fuel bowl by revving the engine a few times with the transmission in the neutral. 8. Remove the sight plug to confirm your setting. A slight trickle should be seen at the threads. Adjust, if necessary. 9. Replace the sight plug and tighten. Some folks will say to do this with the engine running, and I have done that may times. DISCLAIMER - IF you do this have soothing to sop up the fuel and keep a fire extinguisher handy. I've never seen a problem, but I a not responsible for a fire
I think HotRodDon's adjustment instructions are awesome. I just had a similar problem to you. I had a Holly red fuel pump with a regulator. It was still delivering too much fuel. I couldn't seem to dial it in. On advice from someone here, I switched to a Carter fuel pump and it ironed out all my trouble. Just a thought if the adjustment doesn't work. Switched from This: To This: Sent from my iPhone using The H.A.M.B. mobile app
No, I was thinking that instead of dealing with the fuel pump issue, you could move the carb lower, and let gravity be your friend, and do all the hard work of delivering fuel.
Thank you for the float height setting procedure. Replaced with a new float on the rear and set height. Ran lovely for about an hour this morning, then just leaving a job, she struggled to start and pulled away and then died. Started again but didnt want to tick over. Luckily I was only about 400 yards from home. Checked the carb and see that the secondaries are flooding again. I dunno. New carb? Rebuild this one which is only 4 years old and done about 6 thousand miles? Fit a fuel regulator? Fit electronic fuel pump? What you reckon?
How about you describe your fuel system completely, so we can see if there might be a problem with the parts it has now? The hot start flooding thing is something I've encountered more as fuel has been reformulated to be more volatile, for modern fuel injected cars with pressurized fuel systems. I encounter problems more often in the spring/fall when the refiners change the volatility to match the season, but the season doesn't always change at the time the refiners expect. If you have winter fuel, and it's kind of warm out, the fuel will boil in the carb and flood.
Are these Holley needle and seats or? I always had trouble with anything but the Viton needle and seats. Leaky and flooding. Always use a holley kit or parts in a Holley. Something to check anyway. Hey Jim.
I am running a standard mechanical fuel pump straight to carb. Replacement needle and seats are genuine holley. There seems to be a lot of pressure reaching the rear float bowl. Fuel shoots out when I loosen the locking screw and when I remove the sight plug. Can a backfire through the carb screw something up internally. I have been running the truck with this same set up for four years. I did get a carb backfire when the distributor worked loose one time. This problem never occurred in the three years before this happened but happened about 500 miles afterwards and this was rectified with a new needle valve and seat but again only lasted for about 500 miles before recurring and this latest needle valve has only been in for a couple of weeks, not even 20 miles.
Take the adjusting screw and nut off the secondaries and give us a picture so we can see the threads exposed from the needle & seat. That will tell us a bunch. Don't turn the adjuster nut, we need to see it just like it is when you have issues. Put a 5/8ths wrench on it to hold the nut, unscrew the screw, remove the screw & nut.
Backfire "usually" means a blown power valve which will make the carb pig-rich , can't say I've ever heard of a backfire hurting a needle/seat...
Good suggestions. I was taught many years ago that when cranking over the engine that the output end of the high tension coil wire should be grounded to prevent damage to the coil, or else disconnect one of the low tension wires that connects to the coil. Greg
Verygood, That is about the right height, so if you are still getting raw fuel then there is a small piece of trash in the needle & seat. Pull it out & spray with carb cleaner, rattle the needle around. And spray again. You can see how it works, the viton tip can get a small piece of trash inbedded and won't seat proper to seal the fuel. Spraying carb cleaner under pressure and rattling it around will clean it out. Then screw it back in with a couple threads exposed above the gasket (like in your picture) and lock it back down. Should be good to go. Since this has been a recurring problem and you copied the heigth of the old needle & seat there was a good possibility you were making a precise copy of an incorrect setting. The picture tells me the height is close, it should be about another 1/8th turn lower but it will work at that level.
A regulator on ANY Holley is a good investment. A good (or two) fuel filters are another good investment as the needle and seats can trap debris. I suspect debris and or a float that is absorbing or leaking (brass).
Just bit the bullet and bought a new Holley 1850sa and a Malpassi fuel filter regulator. That should sort the damn problem. Thanks for the advice.