Author
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Topic: 650 double pumper installed
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rockafellz Gearhead Posts: 1250 From: San Lorenzo, CA, USA Registered: Aug 2001
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posted 05-18-2003 07:46 PM
Hey All,Hope everyone is having a good weekend with all this great weather!! I rebuilt the 4777-2 650 double pumper yesterday and put it on the motor today. After fixing a few leaks that kept popping up, it fired right up. We adjusted the air/fuel mixture screws (VERY RESPONSIVE!! ) and the idle speed. I sprayed some starter fluid around the spacer and baseplate and no surges. I further checked for vacuum leaks by covering the choke horn with my hand and the motor died within 2-3 seconds. Gave the throttle a few pumps and noticed a big time hesitation. Anyway, I took it for a spin around the block and the hesitation actually stalled the motor. I'm not sure what it is. What is the proper method of setting the accelerator pumps? Gap? Preload? Since rebuild, I did not re-adjust it. I assume this is the cause of the hesitation. What do you guys think? I also used the stock 6.5 power valve. When I actually got the car to surpass the hesitation, it is a BIG HUGE difference!! More responsive and felt more torque going up the rpm band. Just felt all around better. Don't get me wrong the 1850-2 600cfm vac sec. ran fine. But this 650dp is a LOT different. Oh, one more thing, I re-used the nylon washers on the screws that hold the fuel bowls to the main body and 2 of the bolts get a little moist, no drips, but moist. Should I pull them and use the black gaskets in the rebuild kit? Thanks in advance. Erik ------------------ 1966 Ford Mustang 2+2 Mine - Restomod in Progress 1966 Ford Mustang Coupe Dad's - Original Unrestored
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Fastymz Moderator Posts: 10683 From: Reno Nv USA MEM#1240 Registered: Apr 2001
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posted 05-18-2003 08:00 PM
Erik sounds more like the choke to me.I'd use the black gaskets on the bowls. ------------------ SCOOP oddly obsessed with big scoops on little Mustangs 2.26 60'S 14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede. https://mustangsandmore.com/ubb/Fastymz.html
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rockafellz Gearhead Posts: 1250 From: San Lorenzo, CA, USA Registered: Aug 2001
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posted 05-18-2003 08:02 PM
quote: Originally posted by Fastymz: Erik sounds more like the choke to me.I'd use the black gaskets on the bowls.
Ron, I removed the all the choke stuff from the carb (choke plate, rod, linkage, electric choke, etc.) I'll switch to the black gaskets tomorrow. Anyone else? Erik ------------------ 1966 Ford Mustang 2+2 Mine - Restomod in Progress 1966 Ford Mustang Coupe Dad's - Original Unrestored [This message has been edited by rockafellz (edited 05-18-2003).]
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Fastymz Moderator Posts: 10683 From: Reno Nv USA MEM#1240 Registered: Apr 2001
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posted 05-18-2003 08:08 PM
So your saying you dont think it's the choke. Maybe the secondarys are coming in to soon. And dont tell me you removed the secondarys too. ------------------ SCOOP oddly obsessed with big scoops on little Mustangs 2.26 60'S 14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede. https://mustangsandmore.com/ubb/Fastymz.html
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capri man Gearhead Posts: 3138 From: doerun, ga. Registered: Nov 2000
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posted 05-18-2003 09:13 PM
compare the front squrter on the new carb to the one on the old one. it could be to small. i know this is not the correct way to do it but i adjust my pump lever to where it just is touching the bottom of the pump. it takes a lot of trial and error and sometimes just 1/2 turn on the adjustment will make a difference. i think the correct way is to hold the carb wide open and adjust for about .015 clerance between the lever and the pump. just my opinion, i could be wrong. good luck------------------ mike r racing is real everything else is just a game. 81 capri-7.51 @89mph 1/8 1.54 60 ft. http://prestage.com/site/site_display.asp?SiteID=141
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rockafellz Gearhead Posts: 1250 From: San Lorenzo, CA, USA Registered: Aug 2001
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posted 05-19-2003 11:09 AM
quote: Originally posted by Fastymz: So your saying you dont think it's the choke. Maybe the secondarys are coming in to soon. And dont tell me you removed the secondarys too.
Nope, I don't think it's the choke Scoop. And the carb is a mechanical secondary. So it stays closed until it's halfway floored. No more vacuum secondary. It's OK, I was only getting 6-7mpg with the 600cfm anyway. Erik ------------------ 1966 Ford Mustang 2+2 Mine - Restomod in Progress 1966 Ford Mustang Coupe Dad's - Original Unrestored
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Fastymz Moderator Posts: 10683 From: Reno Nv USA MEM#1240 Registered: Apr 2001
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posted 05-19-2003 01:29 PM
quote: Originally posted by rockafellz: Nope, I don't think it's the choke Scoop. And the carb is a mechanical secondary. So it stays closed until it's halfway floored. No more vacuum secondary. It's OK, I was only getting 6-7mpg with the 600cfm anyway. Erik
I have never worked with a DP or a mechanical secondary carb.But it seems like there should be a way to adjust the linkage to make the secondarys open sooner or more late? I'm just trying to help Buddy,not trying to drive you crazy. ------------------ SCOOP oddly obsessed with big scoops on little Mustangs 2.26 60'S 14.9 @ 90.86MPH 65 coupe,351w,C4,Big Boss 429 hood scoop,8"3.40 TracLoc,Cragar SS,Black Suede. https://mustangsandmore.com/ubb/Fastymz.html
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Ryan Wilke Gearhead Posts: 1368 From: Stanton, Michigan 49707 Registered: Oct 2000
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posted 05-19-2003 01:58 PM
quote: Originally posted by capri man: ... i think the correct way is to hold the carb wide open and adjust for about .015 clerance between the lever and the pump. just my opinion, i could be wrong. good luck
As I read it, Mike_R, you are correct. See: http://www.holley.com/HiOctn/TechServ/TechInfo/Instruct.html But as you also mentioned that is merely a point to start from - some custom tuning to his setup may prove to be better for Erik.
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rockafellz Gearhead Posts: 1250 From: San Lorenzo, CA, USA Registered: Aug 2001
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posted 05-19-2003 02:20 PM
quote: Originally posted by Fastymz: I have never worked with a DP or a mechanical secondary carb.I'm just trying to help Buddy,not trying to drive you crazy.
Me neither Scoop. A lot of my projects are 1st timer projects. Oh yeah, I know you're trying to help and believe me I appreciate it a lot. I was just pickin' on ya. Erik ------------------ 1966 Ford Mustang 2+2 Mine - Restomod in Progress 1966 Ford Mustang Coupe Dad's - Original Unrestored
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rockafellz Gearhead Posts: 1250 From: San Lorenzo, CA, USA Registered: Aug 2001
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posted 05-19-2003 02:22 PM
quote: Originally posted by Ryan Wilke: As I read it, Mike_R, you are correct. See: http://www.holley.com/HiOctn/TechServ/TechInfo/Instruct.html But as you also mentioned that is merely a point to start from - some custom tuning to his setup may prove to be better for Erik.
Thanks Mike & Ryan. I'll have to adjust this carb tonight and fix the minor leak coming from the cheap Mr. Gasket dual inlet fittings. Erik ------------------ 1966 Ford Mustang 2+2 Mine - Restomod in Progress 1966 Ford Mustang Coupe Dad's - Original Unrestored
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Ryan Wilke Gearhead Posts: 1368 From: Stanton, Michigan 49707 Registered: Oct 2000
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posted 05-19-2003 04:14 PM
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steve'66 Gearhead Posts: 6150 From: Sonoma,CA,USA Registered: Mar 2000
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posted 05-19-2003 10:18 PM
Erik,It needs more accelerator pumped fuel. If the adjustments don't cure it bigger squirters will. SteveW
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