Gotta Tune this Sucker, HELP!!

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

1

37

Salt Lake City, Utah

Sep 3, 2005

#1

• Sep 3, 2005

• #1

Okay guys I am still having tons of trouble with the car, I finally got my aluminum driveshaft and am dying to take her on the road but can't do it until I get the carb to run. I got screwed over on the carb I purchased so I am using this 750 cfm speed demon with mechanical secondaries for a couple months till I get my money back to buy a mighty demon. I figured I will get the car running with this then switch all the tuning parts I purchased onto the mighty demon and then use the extra tuning capabilities of the mighty demon whenever I get it.

So first problem I can't even get the thing to idle properly so I know this carb has some issues. The idle screws are turned almost all the way in and it is still pig rich. I was thinking power valve but this is my first time building and tuning an engine save for a detroit diesel but diesels are easy so any help will be appreciated.

Like I said it is super rich my oil reaks of gasoline which I know isn't good for seating the rings. It has also developed a backfire from tailpipes recently and I think that also has to do with the fact that it is so rich. I shouldn't be seeing the black smoke coming out the back. The jetting isn't too high with 71p and 79 secondaries, I am at 4000ft elevation, but either way the idle shouldn't be affected by that. Help me get all these tuning woes in order step by step guys so I can get her on the road please!!!!! I am going crazy!!!

 

F

ForceFed70

That's why they call it "dope"

Founding Member

Dec 6, 1999

4,818

1

69

BC Canada

Sep 3, 2005

#2

• Sep 3, 2005

• #2

Could definately be the power valve if it's dumping that much fuel into the engine.

Try replacing it... My last PV cost me $6 and only took about 15min to install.

Edit: Hmmm... just realized you've got a speed deamon carb. Don't know much about them, and the power valve probably can't be bought for so cheap...

 

Max Power

Active Member

Jul 31, 2003

1,774

1

36

St Paul

Sep 3, 2005

#3

• Sep 3, 2005

• #3

Can you break it in with your old carb?

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

1

37

Salt Lake City, Utah

Sep 3, 2005

#4

• Sep 3, 2005

• #4

I don't have the old carb I sold it last year when I needed some cash for the heads. Treat the demon they same as a holley, it uses the same parts such as power valves and accelerator pumps.

 

Great68

Founding Member

May 16, 2002

691

0

16

Victoria BC

Sep 3, 2005

#5

• Sep 3, 2005

• #5

70_Nitrous_Eater said:

Edit: Hmmm... just realized you've got a speed deamon carb. Don't know much about them, and the power valve probably can't be bought for so cheap...

Click to expand...

You can use most standard holley power valves.

 

pabear89

Active Member

Apr 15, 2003

2,126

0

46

High in the Hills of So Ca with the Voices in My H

Sep 3, 2005

#6

• Sep 3, 2005

• #6

Check Float levels and search for an internal leak.

When you shut the engine off quickly look down the barrels of the carb,
if you see light steamy haze coming up then there is a internal leak.
Ie. bad seal,power valve missing check balls.

PB

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

1

37

Salt Lake City, Utah

Sep 3, 2005

#7

• Sep 3, 2005

• #7

The float levels are fine, that steamy haze does exist though. If I pump the carb after that it will really kick up some haze.

I think I may have also figured out why the damn thing has started to run worse and worse. I pulled the number 1 cylinder plug and that thing was soooooooooo black looks like a 50 year old chimney you guys think they are fouled and that could be the reason why my car won't even start anymore.

 

pabear89

Active Member

Apr 15, 2003

2,126

0

46

High in the Hills of So Ca with the Voices in My H

Sep 3, 2005

#8

• Sep 3, 2005

• #8

That Haze rising is a fuel leak into the intake,
It will make it run extreamly rich or flood out.

? Will it start right up after sitting overnite or do you have to crank it some (Filling the fuel bowls)before it starts.

That is a Sure sign of a leaking power valve.


PB

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

1

37

Salt Lake City, Utah

Sep 3, 2005

#9

• Sep 3, 2005

• #9

It definitely has to be cranked a good deal and my oil just stinks of gasoline. So I know it is super rich. I have also pulled a plug and they are black beyond belief so I need to take them all out and clean them up.

 

6

66bluepony

New Member

Nov 7, 2004

75

1

0

Sep 3, 2005

#10

• Sep 3, 2005

• #10

Rich

Are you using a big electric fuel pump without a regulator. What amount of vaccum are you pulling, use a power valve lower than this amount. Maybe just use the lowest you can find.

 

B

bnickel

Founding Member

Aug 21, 2002

5,640

3

77

lubbock, texas

Sep 3, 2005

#11

• Sep 3, 2005

• #11

you might also have too small of an idle air bleed, they are located in the front venturi's at the front of the venturi. it looks like a mini main jet. if the hole is too small it will run rich as hell and not idle for ****. i'd start there first, well after checking the power valve. i've always heard that you want a power that opens at half the manifold vacuum, so if you have 15 inches of vacuum at idle you want a power valve that opens at 7.5, if manifold vacuum is 10 you want a PV rated at 5 and so on. however with it running so poorly i wouldn't go by what the current vacuum reading is, lets just assume for the moment that once you get it running right you have 14 in. of vacuum then start off with #7 power valve. but i'll almost guarantee your biggest problem right now is the idle air bleeds.

 

1

10secgoal

Active Member

Dec 1, 2003

2,801

3

49

San Diego

Sep 4, 2005

#12

• Sep 4, 2005

• #12

It's your PV for sure. Blown or incorrect gasketProlly seeing the haze and white smoke when you shut the thing off too. take the power valve out. It may not even be blown. Make sure to use a paper gasket from holley. Some of these after marker PV come with a teflon gasket that has small indentions in them to align old style PV to the metering block. I chased this same problem for 3 days. The holes line up perfectly with the ring that SHOULD seal the gasket. And the gas dribbles past that. When you fire it and it creates a vacuum, it comes pouring out.It caused me to hydrolock my motor and bend a rod in 3 places. Needles to ssay I was a little pissed at AEM. I had the fuel pump on adjusting the floats and filed the cylinder up with gas. WHAMO.

 

brianj5600

Active Member

Sep 19, 2003

1,964

2

39

Middle TN

Sep 4, 2005

#13

• Sep 4, 2005

• #13

I would look at the throttle plate position first. 4000ft above sea level = more opening to get idle speed = rich idle. Does it have idle eaze?

 

Max Power

Active Member

Jul 31, 2003

1,774

1

36

St Paul

Sep 4, 2005

#14

• Sep 4, 2005

• #14

Also, change that oil right away..

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

1

37

Salt Lake City, Utah

Sep 4, 2005

#15

• Sep 4, 2005

• #15

Yeah I will definitely change that oil as soon as I can get that carb fixed up and slapped back on there. Yes it does have idle ease but I don't know how to use it really. I am probably going to have to wait till tuesday to get all this stuff because everybody is closed for labor day weekend. I am thinking I will set aside $40 to get this damn thing running properly bad news is my vacuum guage took a dump on me so I need to do something about that.

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

1

37

Salt Lake City, Utah

Sep 4, 2005

#16

• Sep 4, 2005

• #16

I am also taking some brake cleaner and a toothbrush to the plugs because they are fouled beyond belief.

 

pabear89

Active Member

Apr 15, 2003

2,126

0

46

High in the Hills of So Ca with the Voices in My H

Sep 4, 2005

#17

• Sep 4, 2005

• #17

With being at that altitude,
you might what to open the rear plate some while you have it apart.
At least check the gap to the rear plate anyway.

It may help your rich idle prob.


PB

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

1

37

Salt Lake City, Utah

Sep 4, 2005

#18

• Sep 4, 2005

• #18

I forgot to mention I was able to borrow my old Holley 4010 from my friend I sold it to, it wouldn't start anymore so I have pulled all the plugs and there is so much soot and crap on them its almost clumped up. I figure that is why it began to run proggressively worse so I will try to time and adjust the valves with this carb while I fix up the other carb so I can get the perfect settings on it.