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awk409ak

Starting Issues?

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Hi All,

I have a 64, 425, dual quad engine (Super  Wildcat).  I've noticed during the winter when the Riv has been sitting a while it becomes hard to start.  I must pump the liven day light out of it and keep pumping as it begins to start.  Once it has been running and turned off it restarts fine.  Been thinking of adding a small electric pump between the tank and mechanical pump.

Any thoughts.

 

Art

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1 minute ago, awk409ak said:

I've noticed during the winter when the Riv has been sitting a while it becomes hard to start. 

 My '67 (and my GP, for that matter) acts the same after prolonged periods (greater than 2 weeks).  It's not a bad thing -- the extended cranking allows building oil pressure before the engine lights-off...  ;)

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Three possibility's  #1 the check valve in the fuel pump is allowing the fuel to siphon back to the tank. To test park car with the front end facing down hill. If the problem subsides you found it. #2 your carburetor is leaking down on extended storage. #3 your accelerator pump is weak. I would suspect #1 is your problem.

 

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Three pumps on each of four cycles usually does it. Maybe more sometimes. If I bought an electric pump it would probably be the only Chinese part on my car. I have heard a lot of guys say they needed to buy a new one.

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Try running premium grade fuel that has no ethanol in it.  The ethanol fuel in the carb could be evaporating as it sits.  Next time, before you try cranking it, pour some fuel into the vent tubes and fill the bowl.  

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If the only time it does it is after long periods of sitting I personally wouldn't bother with an electric pump assuming a very infrequent occurence. I put an ounce or so of fuel in a syringe and squirt it in the air horns of both carbs. It'll fire immediately and that will be enough to keep engine running long enough for the pump to fill the bowls. I know its a bit of a pain but again it depends how often you need it.

Or instead of continuous cranking which heats up the starter and wiring, try cranking it for 4-5 seconds then stop for maybe 10 seconds then repeat, then repeat again.    

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I figure some of it may come from the cat piss gasoline we have to buy now, whether it has ethanol content or not. 

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1 hour ago, jframe said:

I figure some of it may come from the cat piss gasoline we have to buy now, whether it has ethanol content or not. 

It's pure gas, just no lead additives like there were in the day, but no ethanol.  There is enough nickle content in the iron that was used by Buick that no lead won't be a problem.

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Pumping while attempting to start is self-defeating.

 

As mentioned by others, the fuel evaporates out of the bowls. Pumping while attempting to start will give enough fuel to the engine to fire but not stay running, plus the bowls are not being filled.

 

Again, as mentioned by others:

 

(1) Fill bowls with squeeze body or eye-dropper through the vents. OR

(2) Crank the engine WITHOUT PUMPING  for about 10 seconds, then stop cranking, pump the footfeed three times, and start the engine. OR

(3) Electric pump

 

Jon

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If I didn't give my three pumps I wouldn't feel like I was participating.

 

If someone cranked their neck around so they could see my foot behind the console I would give them my old standard "Just humor me".

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I get this ALL the time too. I used a little starter spray in the carb this last time and that helped keep it from feeling too ridiculous on the pumps.

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2 hours ago, carbking said:

Pumping while attempting to start is self-defeating.

 

As mentioned by others, the fuel evaporates out of the bowls. Pumping while attempting to start will give enough fuel to the engine to fire but not stay running, plus the bowls are not being filled.

 

Again, as mentioned by others:

 

 

(2) Crank the engine WITHOUT PUMPING  for about 10 seconds, then stop cranking, pump the foot feed three times, and start the engine. 

 

 

Jon

 

I learned about method number 2 several years ago from this forum. My car sits for 6 months in hibernation over the winter. It works every time. Anytime the Riv sits for an extended period I use this method. No muss, no fuss.

 

Bill

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Agree with Bill that the second recommendation works 95% time . I find that if they sit for more than a few days they are always a little slow to start  . Fact is the same for me personally if  I sit more than 30 minutes in one spot . 😀

KReed

ROA 14549

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Posted (edited)

OK, a bit more time this morning to answer than in my first post.

 

I have this mental image of someone trying to start the car by pumping the footfeed ;)😜

 

The guy is sitting in the driver's seat, gripping the steering wheel so hard that there is blood on his palms from his fingernails, pulling back on the steering wheel so hard it is warped, and pumping the footfeed as fast as he can move his ankle. The air in front of the gentleman is blue and moving rapidly. The guy's face is about the same color as a fire engine, and the ammeter is pegged (empathetic blood pressure gauge ;) )

 

OK, what has happened and probably happening.

 

Modern fuel evaporates. I have a similar setup to the OP in my shop truck (dual Carter AFB's) except my linkage is set up solid instead of sequential for much improved performance, both in driveability and fuel economy . Several years ago, I had the same issue, and after the engine had sat long enough that I didn't burn my fingers, I pulled the airhorn from one carb. The bowls were bone dry! The heat from the engine evaporated the fuel that fast (that 390 produces a LOT of heat). That is when I installed the electric fuel pump. I mounted my pump right at the tank to supply the working original fuel pump (which acts as a pressure regulator, so no external regulator is required). I have a push-button switch on the dash. I can manually energize the pump to fill the bowls for starting. Once the bowls are full, release the push button, pull the choke button (I have manual chokes on both carbs), and start the engine. Once I have oil pressure, the permanent wiring on the fuel pump energizes, and the pump runs as long as there is both ignition on, and oil pressure. Removing either ignition or pressure will kill the pump's operation.

 

The above is my solution.

 

When the bowls are dry, the carburetor (obviously) cannot function. When one pumps the footfeed madly, the accelerator pump will begin functioning as soon as there is sufficient fuel in the bowl to cover the pump inlet check valve (screwed into the base of the pump cylinder), BUT THE FUEL LEVEL IN THE BOWL IS TOO LOW FOR EITHER THE IDLE CIRCUIT OR THE MAIN CIRCUIT TO FUNCTION!

 

So fuel is pumped into the engine, SLOWING the ability of the fuel pump to fill the carburetor bowls to a level where the normal circuits can function.

 

And to dispel one myth often suggested: it is quite impossible for MOST (not all) carburetor bowls to drain back to the tank (unless the owner parks the vehicle on its roof ;) ) Most carburetors have the fuel valve HIGHER than the fuel level in the bowl(s), thus fuel cannot flow backward through the fuel valves. The notable exception to this (there are others) is the Rochester Q-jet. However, Rochester did address the issue in two ways: (1) with the internal fuel filter behind the fuel inlet nut getting an internal check valve, and (2) the use of solid fuel valve seats rather than "windowed" fuel valve seats on some models. Also, Q-jets from 1965 to 1967 had the pressed in well plugs, which could leak. Rochester fixed that issue in 1968 with the spun plug. The carburetor that spawned the term "carburetor leaking down" was the Holley model AA-1 (a.k.a. Holley 94). The economiser valve (a.k.a. power valve) was located in the BOTTOM of the bowl, with a direct passage to the intake manifold. The valve had a neopreme component. A carburetor backfire would normally kill the valve, which opened a direct passage to the intake, and the carburetor WOULD "leak down".

 

Over the last 20 years, I have talked hundreds (perhaps thousands) of prospective customers out of buying either a carburetor kit or a rebuilt carburetor for this issue. One just has to learn how to deal with the fuel. And while ethanol deserves a lot of bad-mouthing, this is not an ethanol issue. There are other aromatics in the fuel which have raised the Reid vapor pressure of the fuel over the years. If anything, the ethanol slightly lowers the Reid vapor pressure (ever have the liquid in your Jim Beam glass empty itself by evaporation?).

 

Jon. 

Edited by carbking (see edit history)
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Thanks everyone for you input.  I'll try the working with it more.  Some of it may be that you are used to getting in your daily driver EFI car and it starts right up.

 

Thanks again,

Art

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48 minutes ago, carbking said:

I have this mental image of someone trying to start the car by pumping the footfeed ;)😜

 

The guy is sitting in the driver's seat, gripping the steering wheel so hard that there is blood on his palms from his fingernails, pulling back on the steering wheel so hard it is warped, and pumping the footfeed as fast as he can move his ankle. The air in front of the gentleman is blue and moving rapidly. The guy's face is about the same color as a fire engine, and the ammeter is pegged (empathetic blood pressure gauge ;) )

 

Hey! That's my routine for demonstrating driving with biased tires when I have an aficionado in the passenger seat.

 

When I start the after a long sit it am more like standing in a cashier line behind a woman digging in her purse for money while I have the exact change in my hand. ------ just humoring her. And equally prepared.

Bernie

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What this man said. I do the same thing

On March 21, 2020 at 6:41 AM, EmTee said:

 My '67 (and my GP, for that matter) acts the same after prolonged periods (greater than 2 weeks).  It's not a bad thing -- the extended cranking allows building oil pressure before the engine lights-off...  ;)

 

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On 3/21/2020 at 6:37 AM, awk409ak said:

Hi All,

I have a 64, 425, dual quad engine (Super  Wildcat).  I've noticed during the winter when the Riv has been sitting a while it becomes hard to start.  I must pump the liven day light out of it and keep pumping as it begins to start.  Once it has been running and turned off it restarts fine.  Been thinking of adding a small electric pump between the tank and mechanical pump.

Any thoughts.

 

Art

 

Hi Art,  

 

Your post has spawned some interesting replies and suggested solutions.  Be comforted that your dual quad starting behavior is quite 'normal'.  Now maybe this isn't what it was like when brand new, but I've had my '65 GS for 37 years and it behaves exactly like yours after a long 'sleep'.  I just pump the gas while cranking and it never fails to (eventually) start. 

 

I will try CARBKING's recommended 10 second crank (no pumping the gas) followed by 3 foot feeds, then crank again to start method.  So that should help wake up or dual quad engines without undue fuss.

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Hi CarbKing:

 

You posted the following:

 

"I have a similar setup to the OP in my shop truck (dual Carter AFB's) except my linkage is set up solid instead of sequential for much improved performance, both in driveability and fuel economy." 

 

Can you describe why a solid vs. sequential dual quad carb linkage is superior? 

 

Would this be something easily done to a stock Super Wildcat ('64-'66) car?  What is the downside to the stock setup?

 

Thanks for sharing your knowledge with the group,

 

 

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"Can you describe why a solid vs. sequential dual quad carb linkage is superior? "

 

Better average cylinder fill density.

 

"Would this be something easily done to a stock Super Wildcat ('64-'66) car?  What is the downside to the stock setup?"

 

NO! Do not try it with the stock carburetors! Possibly it could be done by heavily modifying the stock carburetors.

 

The downside of the stock dual quad is the cylinder fill density on the front cylinders is leaner (except WOT) than the rear cylinders. This will cause a slight imbalance in the engine.

 

What are the percentages? Don't know; but I have been doing solid linkage on customer aftermarket setups for almost 50 years, and, so far (where is the "knock on wood" emoji?) everyone has been happy. There is a noticeable difference in driveability in city driving (less than WOT operation).

 

My shop truck will idle at 600 RPM, and, once the engine is at operating temperature; the throttle may be mashed from idle in first, second, or third gear with zero hesitation. In fourth gear, RPM must be at 1000 or more before mashing the throttle, or the engine will stall.

 

Since the secondaries on both carbs open as needed, one cannot even tell when the secondaries open. When the footfeed is mashed, just raw power from idle to shift point.

 

And the truck gets somewhat better fuel economy at 70 MPH than it did with the single four-barrel (average cylinder fill density).

 

And yes, I am using genuine Carter AFB carbs (that have been "slightly" modified).

 

Jon.

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Thanks Jon,

 

Sounds like i should leave my stock 2x4 setup alone.  It runs pretty darn good as it is.  Might scare the missus if I made the car any faster!

 

 

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On 3/25/2020 at 8:18 PM, 65VerdeGS said:

 

 

Hi Art,  

 

Your post has spawned some interesting replies and suggested solutions.  Be comforted that your dual quad starting behavior is quite 'normal'.  Now maybe this isn't what it was like when brand new, but I've had my '65 GS for 37 years and it behaves exactly like yours after a long 'sleep'.  I just pump the gas while cranking and it never fails to (eventually) start. 

 

I will try CARBKING's recommended 10 second crank (no pumping the gas) followed by 3 foot feeds, then crank again to start method.  So that should help wake up or dual quad engines without undue fuss.

Thanks 65 VerdeGS,

Well I can't say I've had my 64  as long as you have (one year mid May) had your 65, but after posting the question and seeing the reply I did feel a little foolish, but oh well.  It's not that it really bother me, but it does strain the battery with all the cranking.  

I read your post to CarbKing about solid or progressive.  I also read some of Jon articles on his website.  Now I'm not anywhere near an expert on this, but always thought running duals with solid was better for even distribution.  Otherwise the front cylinder are starved for fuel.  Now Jon writes this in his article, but then he said not with stock carbs.

 

So my question is why a stock 425 dual quad setup cannot be setup with a solid linkage.  I used to run my 409 Chevy with dual performance Edelbrocks (not stock) opening both carbs at same time.  Just curious!

 

Art

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425 dual quad setup with solid linkage!

2 x 4 set ups with solid linkage makes sense to me as fuel density 

in the intake would have a more equal distribution.

What other mods would be required (if any) to run solid linkage?

Tom K

 

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