38/38 weber?

[Rasp933]

What up fellas.

Just got this 38/38 weber dges carb with electric choke installed in my l20b engine.but it runs too rich.and also at lower rpms it seems to misfire but pulls hard in higher rpm.i only have 1 idle mixture srew at not even 3/4 s of a full turn out.my spark plugs get carbon fouled .any ideas what might b going on ? Need help guys.thanx

[tr8er]

What is your jetting?

[Rasp933]

Iam not sure on the 38s but wat I did earlier was i swapped my .jets from my old 32/36.into the new 38s n it seems to run fine wit no misfire at low rpms

[tr8er]

and you are 2-4 turns out on your mix?  or 1-2?  

[Rasp933]

Ritecat rhe momennt its at 21/2 turn out

[tr8er]

if you have quick throttle response, and she aint dieseling, scream her down the highway and post vids.  

[KlassicMotion]

Wait a second, Back up.  Your info makes no sense. 

 

I'm sorry to be blunt, but the last thing you should do is change the jets. 

 

Was the 38/38 new when you got it?

Did you read the instructions for proper installation?  (See next questions why I ask that)

***Did you put on a fuel pressure regulator?  That carb can only take 3 psi. max****

***Did you check the float level?***

***Are you sure the gaskets are in properly?***

***Are you sure the adapter plates are on properly***

***Did you check for vacuum leaks?***

 

To me, it sounds like fuel pressure or float issues....

 

 

Are you saying you have one air mix screw at 3/4 turns out, and the other at 2.5 turns out?  Is that after or before you re-jetted it?

 

"If the mixture screw is more than 11/2  turns out turns then the Idle jet is too lean (too small). When the mixture screw is ½ turn or less, then the Idle jet is too rich (too large). These assumptions are based on the fact that the speed screw setting is not opened more than 1/2 turn in. If the speed screw has to be opened1/2 or more turns then this is also an indication of a lean condition usually requiring greater change. At times it may appear to be showing signs of richness or flooding it is really a lean condition. Please understand the need to keep throttle plate as near to closed as possible so as not to prematurely expose the transition holes. This is what causes the visible rich condition, and confirms the need to increase the jet size. JET KITS are available if needed.

EXAMPLE     With the idle speed screw set at no more than 1/2 turn in after contact with the stop lever; and the best idle occurring with the idle mixture screw set at 1 1/2 turns from lightly seating, indicates the need for a larger Idle jet. Achieving the best idle at less than 1/2 turn indicates the need for a smaller idle jet."

 

 

The carb should have been fine out of the box.  I have a 1980 L20B.  My 38/38 DGES works great on factory specs.  I have a cheap fuel pressure regulator from the parts store.  It's set at 2.5psi.

 

-Kyle

[Stoffregen Motorsports]

I'm sorry to be blunt, but the last thing you should do is change the jets. 

 

The carb should have been fine out of the box.  I have a 1980 L20B.  My 38/38 DGES works great on factory specs.  I have a cheap fuel pressure regulator from the parts store.  It's set at 2.5psi.

I understand you are trying to be helpful, and you point out some important things to look at, but saying a carb should be fine out of the box is just not always going to be the case. LOTS of things transpire to cause one engine to falter where another may flourish. The fact that the OP put the 32/36 jets in the 38/38 is what confounds me. Those are two entireyly different carburetors and the jets, while they may interchange, will be nowhere close to realistic (assuminug the 32/36 was jetted properly in the first place).

 

To get a good baseline, re-install the factory 38/38 jets and fire the car up and try to get it to idle nicely. Once that is done, install a new set of plugs and go drive it. Drive it hard and do what is called a plug cut (full throttle acceleration then kill the ignition, roll to a stop and pull the plugs and take a peek). Once the full throttle jetting is established, then fine tuning may begin.

 

This is not how the book may say to do it, but it is one way to jet your car.

[Rasp933]

I change the jets from my old 32/36s n it seems to run fine.and the mixture screw is 21/2 turn out.

[Rasp933]

But I haven't checked my s plugs yet.it was really getting late at night

[Rasp933]

O n I also changed the secondary jet too

[Stoffregen Motorsports]

So you've fixed it? No more problem?

[Rasp933]

Looking dat way but noy 100% sure.i still have to do fine tuning

[banzai510(hainz)]

I bolted a38/38 to a L16 and it ran fine. was overjetted as it came from a Landcruiser. Plugs andintake manifold was black inside but ran good. motor had a Schneider cam and U67 head

 

You have electronic ignition?  If yes thats good.if points maybe get a electronic ignition . I just have a Pertronic but maybe a Matchbox with a EI coil might be better

[Rasp933]

Iam running the gaps at .044 wit match box.u think I should make the gap smaller since iam using bigger carb?

[Rasp933]

Iam running the gaps at .044 wit match box.u think I should make the gap smaller since iam using bigger carb?

[KlassicMotion]

Factory says .40 gap with matchbox

[KlassicMotion]

I understand you are trying to be helpful, and you point out some important things to look at, but saying a carb should be fine out of the box is just not always going to be the case. LOTS of things transpire to cause one engine to falter where another may flourish. The fact that the OP put the 32/36 jets in the 38/38 is what confounds me. Those are two entireyly different carburetors and the jets, while they may interchange, will be nowhere close to realistic (assuminug the 32/36 was jetted properly in the first place).

 

To get a good baseline, re-install the factory 38/38 jets and fire the car up and try to get it to idle nicely. Once that is done, install a new set of plugs and go drive it. Drive it hard and do what is called a plug cut (full throttle acceleration then kill the ignition, roll to a stop and pull the plugs and take a peek). Once the full throttle jetting is established, then fine tuning may begin.

 

This is not how the book may say to do it, but it is one way to jet your car.

 

I will agree to disagree. 

 

In my experience, if you buy a carb new, and you buy a carb that is marketed for your application, and you set it up as per the instructions (setting the mixture, Idle, choke, float level, and fuel pressure), then you should not have running issues with that carb.  The carb may not run to it's optimum performance, but it should run without major issues as the OP is experiencing....

 

Whether or not your engine has other underlying issues, is a totally other subject all together.

[KlassicMotion]

Rasp933,

Did you put a fuel pressure regulator in line?

[nismo dr]

 

In my experience, if you buy a carb new, and you buy a carb that is marketed for your application, and you set it up as per the instructions (setting the mixture, Idle, choke, float level, and fuel pressure), then you should not have running issues with that carb.  The carb may not run to it's optimum performance, but it should run without major issues as the OP is experiencing....

 

 

 

 

I've had multiple weber...errrr empi weber clones that have all come new out of the box with completely different jets

[Stoffregen Motorsports]

Not many places sell carbs pre-tuned for application. And the OP didn't say anything about having bought it new. For all we know it was installed on an FJ40 in Colorado. An L20B running at sea level just isn't going to require the same jetting as that.

[KlassicMotion]

Well, I suppose there is the problem of the cheap knock off Webers versus the real Webers.  I can't remember, some are made in Spain, Italy, and then Taiwan or something?  Supposidly if your electric choke is white plastic (versus black), then you have the good Weber!?

[KlassicMotion]

Not many places sell carbs pre-tuned for application. And the OP didn't say anything about having bought it new. For all we know it was installed on an FJ40 in Colorado. An L20B running at sea level just isn't going to require the same jetting as that.

 

True, that's why I asked the questions I did.  We know nothing of his situation.  And it's hard to diagnose without the whole story.

[KlassicMotion]

 

 

 

 

I've had multiple weber...errrr empi weber clones that have all come new out of the box with completely different jets

 

 

Empi, Empi used to be good.... That's all I will say.

[Rasp933]

No fuel regulator in line. But my 32/36 was rebuilt like 11/2 yrs ago.so dey might have changed.it.also as of rite now iam only using secondary bore which I have at 11/2 turn out n it had eliminated the backfire which the engine was expriencing.primary bore is closed all the way.ie the one close to valve cover.