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Discussion Starter #1
Now that the new tank has arrived, I am thinking about running an electrical fuel pump at the tank and eliminating the mechanical unit on the motor. Any recommendations or problems that have been encountered would be appreciated. I am a less than happy about the nuber of times I must pump the pedal to get the car started and then when it is just a little too warm outside, she has a tedancy to die on me. I have recently rebuilt the carb (Holley-don't get me started...) and I have no problem passing the E-test here in Colorado (yet).
Thanks all. --MG
 

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I dont think a electric fuel pump will fix your problem with starting . Sounds like you need some choke adjustments. Is your holley a electric or manual choke? Pumping the throttle is part of a carberated engines way of life. If you take a lot of pumping you may want to check your accelarator pump to see if its giving the full squirt you need. If its been rebuilt it may simply out of adjustment. If it dies after it starts along with the choke being out of adj the fast idle cam may need looked at. A electric fuel pump maynot hurt but I dont think there as reliable as a mechanical pump. Put a fuel pressure gauge on the fuel line going to the carb and check the pressure while cranking the engine over. 4-6 lbs is plenty in most cases. If you do go with a elec pump, you are right they are to be mounted as close to the tank as possible with the filter between the pump and carb. mm
 

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I agree with MM the mechanical pump probably is fine. If you do decide to go with an electrical pump you should leave the mechanical pump on too as a back up. That way if your electrical pump dies you'll have a back up [they do die to - i have fond memories of pushing my friends 66 mustang around town do to a holley fuel pump that crapped out] - Chad
 

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Discussion Starter #4
Thanks Guys... My intention with the electric pump was to get around what seems to be some vapor lock problems I have encountered. The Holley has been rebuilt and is the center float all mechanical 4-brl variety (?#). What I was thinking on the mechanical bypass was to have constant fuel at the carb. This thing dies out after short drives and really doesn't run that hot, motor temp wise. My floats need to be set relatively low to pass the emission test and I think the problem is that it gets a little toasty too quick. I was also debating a carb spacer but do not know if clearance would be an issue. I already have a performer manifold and a chunk of aluminum (3/4") under the carb now.
--MG
 

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Carb spacer

Your car should not be experiencing vopor lock. They wouldn't have designed the car the way they did if they'd always be crapping out. Thousands and millions of cars did quite nicely with 'just' a mechanical pump. The first thing to do is to get rid of that aluminum carb spacer. Aluminum is a tremendous conductor of heat. Use a plastic (phenolic) spacer instead. You may also want to block off the heat risers from the heads to the manifold. (I think Performers have a heat passage -- too many years....)

Do not set the float levels low on your Holley. You'll create more problems than you solve. They were designed to have the fuel at a critical level. The jetting will be totally messed up if you set low. The venturis and more specifially the boosters require a certain ammount of suck to get a certain ammount of fuel. With the fuel level set low, you're requiring a stronger vacuum (more air flow) to get the fuel through the boosters. The air bleeds (those four small holes inside the air horn) are critical to a Holley functioning right. If they're blocked, you're screwed. FYI, the replaceable jets on the Holleys are basically there for full-throttle fuel flow restriction, not idle or part throttle metering.

I would strongly suggest you get a book on Holley carbs and follow the book's recommendations for tuning. I've seen more holley's destroyed by misinformed shade-tree mechanics. (holes drilled in throttle plates, screws installed in linkage to alter timing of secondary operation, missing checkballs, deformed checkball seats....)

Good luck with your carb tuning!
 
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