Tuning a single 40MM Kadron?

[mharney]

This shouldn't be this tough.

One way a carb can run with the idle screw bottomed is a crack in the carb.

Another is if your idle speed (throttle stop) is screwed in too far, cracking the throttle too much. This will start to get into progression, and the mixture screw no longer matters much. Make sure you don't have it screwed in too far. Back it out until it doesn't touch, and then in until it does, and then maybe another turn or so to start. Then play with the mixture screw.

Another is if your accelerator pump nozzle is drooling fuel. Look down and see if the nozzle drips.

Another is a float that is stuck open or a dirty needle and seat not allowing it to close correctly.

And another is excessive fuel pressure.

For excessive fuel pressure, take a pair of vise grips and set them to be tight enough to just squeeze the fuel line closed. If you do this, the pressure to the carb will drop to zero pretty quick, within about 10 seconds the symptoms related to excessive fuel pressure will go away. This could also cause a stuck float or needle and set problem to stop causing it too.

Within a minute or two it should die from no fuel in the float bowl though, so don't get the two confused.

[A.J.Sims]

Sorry for sounding like i snaped at you. I did not mean it that way. You will need to fix the first things. That is not a fuel regulator,its a fuel flow regulator. Take it back or toss it at a bird in the sky!
The more i read your post the more i want you to fix the first problem.



I need some info on how to tune the Empi Single Kadron 40MM carb. Everything I have found is for the dual setup. Seems to be just mixture and idle. What is a good starting point for the mixture? The carb came set at 1-1/2 turns out.
For some reason the further in I adjust the mixture screw the better it gets. To the point that is all the way in. Even all the way in the car doesn't run great. It backfires and shoots fireballs out the stinger. (car is a Baja)

1:timing and or wrong dizzy and or dizzy curve and the carb is not adjusted yet.Its assembled and boxed up and sold to you. Thats it.... not tuched by a carb tec, car tec or even a phone tec!!!!
2: Fuel press is wrong. (kadrons like lower than 2.0lbs.)



I talked to someone that has this carb setup and he just bolted his on and it ran great. I think I may have issues other than the carb. Anyone out there running this carb?

[sloans265]

Check with your local hotrod shop for a pressure gauge. They usually carry smaller gauges that have seperate t-fittings for different size hose. Also easier to find one there that reads 1-15lbs. (for carbs) since a lot of chainstores MIGHT carry one for fuel injected motors . Easy to install between pump and carb for dialing in pressure then remove.

Also like everyone else said go to Sims website. I had my own carbs and got linkage & jets from A.J.. His site walked me through the rest. The little problems I had were remedied after I got my pressure right.
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1970 Lotus White Panel
In search of any Pensacola Fla dealership items

[thrown_hammer]

Mharney,
I will make sure the idle screw is just touching. I will also do my best to look at the accelerator pump nozzle and see if it is dripping fuel but until I know what my fuel pressure is I will hold off on any adjusting. I will try the visegrip trick and see what happens.

A.J.,
I know this is frustrating and you are offering free advice. I don’t know a lot about VW mechanicals yet. I appreciate you taking time to try and help me out. I have a stock vac advance dizzy in the garage. Can I use that with this carb or do I need the lowwbugget.com SVDA? I am going to go through the steps for tuning the carb again. Also what jet sizes would you recommend? The carb has a 55 idle jet. I haven’t looked into the main jet yet.

Sloan265,
We have no local hotrod shop. I am going to order one from Jegs. They usually ship to my house pretty fast. I have spent a lot of time at A.J.’s website. Eventually this stuff will sink in.

To everyone,
My plan of attack as of right now:
1) Make sure carb idle screw is set right.
2) Verify accelerator pump isn’t drooling.
3) If drooling verify fuel pressure before adjusting.
4) Verify fuel pressure.
5) Adjust accelerator pump if nessascary.
6) Set air/fuel mixture screw.
7) Once all the above is set and verified if still have issues put in vac advance dizzy.
Look good?
Feel free to modify my to do list as you see fit.

EDIT: Just ordered a Holley pressure regulator and a 0-15PSI pressure gauge.
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[sbnova]

This is all you really need;

Here is one for sale for under $20;
http://cgi.ebay.com/ebaymotors/Vacuum-Fuel-Pump-Te...dZViewItem

These are for sale at every auto parts store around here. You dont need a fancy permanent mount version, just something you can hook up during tune-up time.

If your floats are too high, or running over slightly, it can cause you to run rich without leaking externally. A recent test in a Hot Rod magazine showed float level changes of 1/4 inch could richen the air fuel mixture by .5 ! (I know it doesnt sound like much but it is)

High or overrunning floats can drip from the venturi while the engine is running. A very valid point was made earlier as to the throttle blade position (idle screw setting). If its set too high to achieve a decent idle, it can uncover a fuel transfer to main metering- adding extra unwanted and unmeterable fuel at idle.

I will admit, I am not familiar with Kadrons/Empi's, but I know tuning. Engine dont run on air, find the reason its getting fuel so you can truly set the idle mixture and go rom there. Get a simple gauge, and either adjust your regulator and/or shim the pump to lower the fuel pressure.
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Link to my build thread- Updated 6-6-07 http://www.thesamba.com/vw/forum/viewtopic.php?t=210613
check my sites to see my work;
http://www.cardomain.com/ride/1564293 (bug)
http://www.cardomain.com/ride/448794 (Vette,Nova,Typhoon)

[krusher]

Please fix it , I think I am gonna cry.

Keep going you can do it

[thrown_hammer]

Got the Holley fuel pressure regulator and fuel pressure gauge. Installed and set to 1.5 lbs. Guess what.....Still can turn in the air/fuel mixture screw all the way in. The accelerator pump tube doesn't seem to be dripping any fuel. I actually cranked the nut WAY in and it made no difference.

1) Make sure carb idle screw is set right. DONE.
2) Verify accelerator pump isn’t drooling. DONE.
3) If drooling verify fuel pressure before adjusting. PRESSURE GOOD/NO DROOL.
4) Verify fuel pressure. DONE.
5) Adjust accelerator pump if nessascary. ADJUST/NO CHANGE.
6) Set air/fuel mixture screw. ALL THE WAY IN.

What does this tell you guys? Do I have a jetting problem? Joel Mohr said earlier in the thread he has the same carb and had to go to a 50 idle jet and a 150 main. He has an 1835 engine. What jetting should I have for this carb with a stock 1600DP? Or do you guys think it is something else?
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[thrown_hammer]

UPDATE:
I can crank the idle screw out and the car will die. But if I turn it in just enough to keep the car running The air/fuel mixture screw can still be turned all the way in and the car runs.
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[thrown_hammer]

Just talked to Joe at lowbugget. He says the jets that are in the carb should be the right size. So it’s not jets, not fuel pressure, not out of adjustment idle screw, not out of adjustment accelerator pump, not low compression. Tonight I plan to take the top of the carb off and verify the float is working. That is my last idea. After that I give up. I will either just change the plugs once a week or sell it.
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[thrown_hammer]

What should the float level be? Can't seem to find that info anywhere....
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[thrown_hammer]

Pulled the top off the carb. Needle is not stuck and fuel level in the bowl is 3/4" from the top. Don't know what it should be but that is what it is.

I suppose the only thing left is an air leak somewhere? I sprayed all over with carb cleaner and it didn't rev up....maybe I should get new gaskets for between the intake runners and heads? The gasket between the carb and whatever the middle piece is called is new as well as the rubber things between the middle thing and intake runners.
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[thrown_hammer]

Wouldn't an air leak make the engine run LEAN?

EDIT: My car seems to run the same no matter what carb I have. I have had a Mocar 34 pict-3, a Solex 34 pict-3 rebuilt by me, and now this new 40MM Kadron. Seem to have the same issue, little to no adjustment and car runs rich. Let's back up a minute. Instead of concentrating on why the carb makes the engine run this way lets ask why the engine is making the carb ACT this way..... I think with your help I have checked and verified everything with the carb.
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[thrown_hammer]

Okay I unhooked the accelerator pump let the car warm up until it was idling normal and the choke was open. Car still runs with air/fuel mixture screw all the way in. I crimped off the fuel hose and it would still run adjusted all the way in. Does this mean I either have an overactive float or a JUNK carb? Or something else completely?

What should my float level be set at?
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[Loopole]

you have done your due dilegence, demand a refund, something with the carb is wrong. get away from the centermount carb, unless you have a hot air source for the carb and manifold heat from a stock exhaust it aint gonna run very well, period. the fuel is not making it to the cylinders in a vapor. buy a quality dual carb kit from someone like aircooled.net, and you wont be disapointed.

[thrown_hammer]

Am I being ignored because I am an idiot or because we are all out of ideas?

Air/fuel mixture screw has no effect. Car runs rich even with screw turned all the way in. These are the facts:

1) Verify fuel pressure < 2 lbs with Holley regulator and oil filled pressure gauge.
2) Crimp fuel hose shut with no effect on mixture screw.
3) Idle set as low as possible 400 RPM.
4) Float level at ¾” from top of float bowl.
5) Needle valve moves freely.
6) Verified correct jets with lowbugget.com (Although I am going by the # stamped on the jets and not by actual gaging.)
7) Cannot locate any vacuum leaks.
Accelerator pump set per instructions.
9) Verify accelerator pump is not drooling both visually and by unhooking completely.
10) Verify timing is set at 34 degrees total advance.
11) Compression is at or above 105 pounds in each cylinder.
12) Valves are set at .006” clearance. Remember it hits 0 degrees around here.

I think I am calling the place where I got the carb. I don’t see how it can be anything other than a bum carb at this point.

Does anyone think that ordering hand reamed and inspected jets from A.J. would fix this problem?

Also I don't think the 009 dizzy would cause this particular problem would it? It may not be helping but I can't understand how a certain kind of Dizzy could cause the engine to run rich with the mixture screw all the way in......
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[Loopole]

i had a bad experience with kadrons, they ran fine on my first engine, a very stockish 1776, when i went to the second engine a 1776 with bugpatch heads and a engle 110 it ran sooo bad, i spent endless hours trying to get it to idle smoothly, it ran very rich at idle and off idle, it would literally foul plugs if i didnt take it out on the freeway and run it hard, dellortos fixed the problem completely. it could be a cracked carb, but i think most likely it has something to do with fact that this carb was not made for a centermount application and you have insufficent manifold heat. this would also explain why your stock carb also ran rich.

an easy way to test for this problem is let it idle for a little bit, dont get the engine real hot, pull the carb off very carefully and be sure to not hit the throttle so as to not activate the accelerator pump, then pull off one of the manifolds, run your finger around on the inside of the head, and if you get a wet gassy black finger, you have your answer.

[thrown_hammer]

I just got off the phone with A.J. Sims. I still have a glimmer of hope. He said my float or needle/seat have to be the issue. He gave me a few tips. I am off to disassemble the top end of the carb again and try what he suggested. More in a little bit.
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[Loopole]

i had a bad experience with kadrons, they ran fine on my first engine, a very stockish 1776, when i went to the second engine a 1776 with bugpatch heads and a engle 110 it ran sooo bad, i spent endless hours trying to get it to idle smoothly, it ran very rich at idle and off idle, it would literally foul plugs if i didnt take it out on the freeway and run it hard, dellortos fixed the problem completely. it could be a cracked carb, but i think most likely it has something to do with fact that this carb was not made for a centermount application and you have insufficent manifold heat. this would also explain why your stock carb also ran rich.

an easy way to test for this problem is let it idle for a little bit, dont get the engine real hot, pull the carb off very carefully and be sure to not hit the throttle so as to not activate the accelerator pump, then pull off one of the manifolds, run your finger around on the inside of the head, and if you get a wet gassy black finger, you have your answer.

[thrown_hammer]

A.J. told me to take the top of the carb off turn it upside down and blow into the fuel inlet. He said if I could overcome the needle and seat by just blowing in the inlet they were bad and needed replaced. There was no resistance at all. I verified this test with the two other Solex style carbs I had in the garage and I couldn't blow past either of those.
So I ordered a rebuild kit and jets from A.J. so I would be sure to get the correct shim for the needle and seat. Also ordered a main and idle jet from him just for insurance purposes. Heck if I was sold a Brand new carb with a bad needle and seat who knows what size the jets are?

Stay tuned.

P.S. That A.J. Sims guy really is the man.
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1974 Superbeetle Bright Orange

Keeper of the Titanium Monkey

[Loopole]

if that was the case when you looked down the carb throat while the engine was running you would see fuel, lots of it running out the float bowl vent tube, send it back, also you saw no changes when you pinched the fuel line off, didnt run any different, you are wasting your time.