more carb problems
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New User
Joined: Oct 2003
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more carb problems
a couple weeks ago i put a manual choke on my holley 650 double pummper because i was having problems keeping my truck running when it's cold ,so put the manual choke on adjusted float levels and mixture also tuned the idle up a bit .and it was a holley choke kit. needless to say my carb problem still exists. when my truck is running it runs just fine idles great sounds good but wuen it's cold i always have to have my foot on the pedel just to keep it running , when i use the choke part way it does nothing and all the way floods it out .carb's are my downfall when it comes to working on engines .I'm ready to switch to elderbrock ,im kinda hoping it might be something i have over loocked. any thoughts whould be great:
Senior User
Joined: Jun 2003
Posts: 113
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if you don't already have an msd 6a box or something similar those can help alot.........durasparks are great but the msd really helps in situations like yours..........if you already have a 6a or you want to keep your duraspark, and if you live in a really cold climate, you may want to check your thermostat......big truck, big radiator equals too much cooling.........do you know what temp it runs at???
you may also be able to fabricate some kind of heat riser to air filter tube to get some warm air into the carb....
as for the carb itself, if the jetting is in the ball park, and the power valve is the right one for it, it's probably gonna need one of the above mentioned items..........( heat riser, ignition or different thermostat).
this is assuming ofcourse it runs fine when warmed up well and or in warmer time of year.
you may also be able to fabricate some kind of heat riser to air filter tube to get some warm air into the carb....
as for the carb itself, if the jetting is in the ball park, and the power valve is the right one for it, it's probably gonna need one of the above mentioned items..........( heat riser, ignition or different thermostat).
this is assuming ofcourse it runs fine when warmed up well and or in warmer time of year.
Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
The first thing I do with a Holley is throw the choke PLATE away. You dont need that thing to start anyway. What sounds like is happening is when you pull the choke, it is upping the idle, but pulling the plate too far shut and basically choking the motor with too much fuel/not enough air.
I usually just pull the plate out and only use the high idle part of choke. You can then pull it out to your hearts content and it only revs higher, instead of cutting the air off.
You can also adjust the amount of high idle also. I crank the screw up a bit to get it to hold throttle open more with less choke pulled.
Larry
PS: If you need some assistance in getting it apart, I'll send you a picture of mine. The newer carbs you just pull the blade out(with visegrips) and then remove rod and linkage. The older carbs you need to remove the two small screws and then slide plate out of rod.
I usually just pull the plate out and only use the high idle part of choke. You can then pull it out to your hearts content and it only revs higher, instead of cutting the air off.
You can also adjust the amount of high idle also. I crank the screw up a bit to get it to hold throttle open more with less choke pulled.
Larry
PS: If you need some assistance in getting it apart, I'll send you a picture of mine. The newer carbs you just pull the blade out(with visegrips) and then remove rod and linkage. The older carbs you need to remove the two small screws and then slide plate out of rod.
Last edited by Freightrain; Dec 15, 2003 at 09:17 AM.
Postmaster
Joined: Jan 2003
Posts: 3,775
Likes: 2
From: Conway Arkansas
I agree with you there freightrain
My 750 has had the choke completely milled off of it
I had no problems getting my 390 startd on any cold day, just as long as the battery was good.
Fired right up, gave it a bit of throttle for a few mins (kept it around 1200 rpm) and she was good to go
My 750 has had the choke completely milled off of it
I had no problems getting my 390 startd on any cold day, just as long as the battery was good.
Fired right up, gave it a bit of throttle for a few mins (kept it around 1200 rpm) and she was good to go
Posting Guru
Joined: Jul 2003
Posts: 2,232
Likes: 1
From: Colville, Washington
I agree that the carb is overchoked, but depending on where you live removing it might be too much. I have for years cut the plate at an angle from top edge to near the center of the plate against the rear choke tower wall. That allows some choke action and allows more choke movement for fast idle without flooding.
I don't know if the description is good?
Basically you cut a fair sized triangle ouy of each upper corner!!
Last edited by Putt; Dec 15, 2003 at 10:43 PM.
