75 Imperial Interm. Crank no start

[mgk]

Hello All,
My 75 Imperial tends to crank and not start after sitting for longer then a week or so. The battery is fine 12.6 and good cranking. Also getting fuel. It seems ignition related . After cranking on it excessively it will later start. After that it seems fine starting as long as you don’t let it sit unstarted for longer then about a week. Hoping to ask for help on where to start/check…? Many thanks

 

[CBODY67]

Is the automatic choke blade fully closing? Choke pull-off working AND adjusted correctly? Strong fuel from the accel pump nozzle?

Just curious,
CBODY67

 

[mgk]

Is the automatic choke blade fully closing? Choke pull-off working AND adjusted correctly? Strong fuel from the accel pump nozzle?

Just curious,
CBODY67

Hi there, yes to all. This seems like ignition issue because it doesn’t even “want” to start
Thanks for your time-appreciate you.

 

[mgk]

Will do -many thanks

 

[CBODY67]

NOT to sound flaky, but where is the fuel "flowing back" from? The main fuel line, which attaches to the carb at a level even with the needle and seat? IF the fuel is that high in the float bowl, it seems it would be running other laces, too. Like into the venturis?

My respectful question is how is the fuel leaving via the fuel supply line if the fuel level in the float bowl(s) is below the top of the needle/seat assy. Fuel evaporation, as mentioned in other threads and posts in here and elsewhere, seems more possible, by comparison.

Are there any "well seals" in the TQuad carburetor, which attach to the bottom of the float bowl itself, as in the Rochester QuadraJets, which were known to leak-down into the intake manifold?

What might I not be seeing?

Just trying to figure out how "back flow" is supposed to be happening. No more, no less.

Respectfully,
CBODY67

 

[cbarge]

Are there any "well seals" in the TQuad carburetor, which attach to the bottom of the float bowl itself, as in the Rochester QuadraJets, which were known to leak-down into the intake manifold?

Yes. Each bowl has a tiny O ring. If pinched shrunk or broken it will empty the bowls.
This affects the floats and ditto gas runs into the intake.
Not to mention todays corn swill fuel evaporates quickly.
Even the best running carb and/ or engine will do a long crank after a week sitting and also long crank when hot.
Priming the carb after a long sit helps.
A squirt of brake cleens or a small squeeze bottle of gasoline into the carb vent tubes to fill the bowls work every time.
Another thing to check is wear on the fuel pump pushrod.
They are known to give owners fits.
Hope this helps

 

[CBODY67]

One way to check for bowl drainage into the intake manifold might be to see if there was a stronger-than-normal hydrocarbon smell in the oil on the engine's dipstick, before the engine is started after its sitting for days? Of course, the pcv system would evacuate the hydrocarbons form the gasoline after the engine is run for a while and gets hot.

Just some thoughts,
CBODY67

 

[Mr C]

Before jumping on the TQ cracked bowl/ O ring issue. I'd like to know what the definition of "excessive cranking" is...all of my classics need cranking after they have sit for a while. It's to the point that I know that ,after sitting a week, my Cordoba (360 2bbl) needs three cranking attempts before it catches.

Before anyone says...no my cars are not prone to flooding or any symptoms of the carb dumping raw fuel in the intake. They just all need to refill the bowls after sitting. I find that today's fuel is very prone to evaporation...it does not last like the old stuff used to. Which is why I love the TQ...that plastic bowl really helps with vapour lock issues that I have had with my AFBs and today's gas.

I think this Imperial is just "normal" ...he did say it happens if it's been sitting over a week or so. My bet is that his car are like mine are.

 

['66 Fury I]

My solution to this issue was to install an electric fuel pump in-line before the mechanical pump. It is wired to a momentary switch under the dash and is used to refill the carb after sitting. The sound of the pump changes when the carb is filled and then the engine will start on the first crank. Works for me. Lindsay

 

[Big_John]

My solution to this issue was to install an electric fuel pump in-line before the mechanical pump. It is wired to a momentary switch under the dash and is used to refill the carb after sitting. The sound of the pump changes when the carb is filled and then the engine will start on the first crank. Works for me. Lindsay

This is exactly what I've done too. You don't need anything expensive, a cheap Amazon or eBay pump will do it.

 

[mgk]

Before jumping on the TQ cracked bowl/ O ring issue. I'd like to know what the definition of "excessive cranking" is...all of my classics need cranking after they have sit for a while. It's to the point that I know that ,after sitting a week, my Cordoba (360 2bbl) needs three cranking attempts before it catches.

Before anyone says...no my cars are not prone to flooding or any symptoms of the carb dumping raw fuel in the intake. They just all need to refill the bowls after sitting. I find that today's fuel is very prone to evaporation...it does not last like the old stuff used to. Which is why I love the TQ...that plastic bowl really helps with vapour lock issues that I have had with my AFBs and today's gas.

I think this Imperial is just "normal" ...he did say it happens if it's been sitting over a week or so. My bet is that his car are like mine are.

Hi there,

Apologies for the late response, have been working like crazy. My imperial will literally crank for a long time (like several cycles and no fire at all)
I can wear the battery down trying to start it and have to recharge before finally getting it to start.

Thanks for your thoughts

 

[Big_John]

Hi there,

Apologies for the late response, have been working like crazy. My imperial will literally crank for a long time (like several cycles and no fire at all)
I can wear the battery down trying to start it and have to recharge before finally getting it to start.

Thanks for your thoughts

Here's what you do.

The next time the car has sat for a while, get yourself a squirt bottle or something similar and put a bit of gas in it.

Now take the air cleaner off and put a bit of that gas in the bowl vent on the carb. Not too much, but it has to be enough to at least partially fill the float bowls.

Now try to start it. If it starts right up, and I'll bet it does, then the problem is the gas evaporating out of the carb.

 

[Clover]

Hi there,

Apologies for the late response, have been working like crazy. My imperial will literally crank for a long time (like several cycles and no fire at all)
I can wear the battery down trying to start it and have to recharge before finally getting it to start.

Thanks for your thoughts

When it finally fires, is it as you’re turning the key back to “run”?