Author Topic: Setting Choke  (Read 2503 times)

Offline 1Cobra427

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Setting Choke
« on: December 01, 2012, 11:27:02 AM »
'77 C20 w/ 454 and orig carb.  Setting the choke (press gas pedal twice then little gas as starting catches, and still have to turn over, and over and over until the engine cranks.  Truck sits week or so at a time.  Is this normal??

Offline zieg85

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Re: Setting Choke
« Reply #1 on: December 01, 2012, 11:34:31 AM »
No it is not normal.  Sounds like the carb is emptying over time.  The fuel pump could be culprit.  All my trucks with mechanical fuel pumps do this.  I just deal with it and think of it as a theft deterrent.  My 85 C20 is the worst but like my 2 boys, each has a different personality and that is what makes them special.
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline bd

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Re: Setting Choke
« Reply #2 on: December 01, 2012, 11:48:36 AM »
Having trouble duplicating what you're trying to say.  No two engines start exactly the same - some are temperamental.  Two distinct scenarios might be occurring:

1)  Your flooding it by pressing the pedal too many times(?)

2)  As Zieg stated, the carburetor may be draining of fuel during the week, because of internal leaks and/or back-siphoning through the fuel filter.

The solution to the first scenario is to modify your starting technique.

The solution to the second scenario is twofold:  (1) overhaul the carburetor and reseal the fuel well plugs with epoxy, (2) install a later style fuel filter under the inlet nut of the carburetor that has an integrated check valve.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 1Cobra427

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Re: Setting Choke
« Reply #3 on: December 01, 2012, 12:46:42 PM »
I am pressing the gas pedal twice before anything to set the choke.  Friend said I should hold the gas pedal down during cranking might help.  I do not want to drop $$ into carb rebuild this close to Christmas presents if I can avoid it!!   It starts just fine after a few minutes of driving and warm up.  New truck and I am learning as I go.

Offline zieg85

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Re: Setting Choke
« Reply #4 on: December 01, 2012, 01:02:12 PM »
I have to pump my gas pedal as I am cranking.  They all start that way but the 85 C20 takes the most pumping if it sits a week or longer.  If I drive it daily, 1 pump to set the choke and it fires up like it did when it was new.
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline bd

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Re: Setting Choke
« Reply #5 on: December 01, 2012, 01:06:02 PM »
I'm with Zieg, it sounds like you're using the right method to crank.  The problem you're describing probably won't get any worse than it is, now, so you can delay any repair until warmer weather.  You could always try replacing the fuel filter with the type that has the one-way check valve for about $3 (see image) w/o removing the carb, but leaking fuel well plugs are the usual cause of your complaint.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)