Weber Jet settings 190sl

Hi Jim, Robby, Mike, and Fellow enthusiasts,

I've been fiddling with the jets in my 190sl to complete the installation, now that its a fine sunny day in California.

Anyhow the HP Books Weber tuning guide says my car should have

125 Main Jet, F11 Emulsion tube, 200 Air Adj with
50F9 Idle jet, and 45 accell pump jet

The kit that I bought from JAM enginering said I shoul have

125 Main Jet, F2 Emulsion tube, 200 Air Adj with
50F9 Idle Jet, and 45 acell pump jet


What is actually in my carbs as delivered

115 Main jet, F11 Emulsion tube, 200 Air Adj with
45F9 Idle jet and 40 accel pump jet


My car runs pretty well with these settings, but has a problem with bogging on quick throttle application anywhere between 1000 and 2300 rpms. The plugs are on the lean side, but not too bad.

Previously when I had the 42 DCOE's in there, the car was set at

145 Main jet, F7 Emulsion tube, 190 Air Adjust
50F8 Idle jet, and 40 accel pump.


Anyhow, I'm going to set the jetting to the HP book suggestions for starters. I'm curious what settings the rest of you run.

Thanks,
Eric

[Robby Ackerman]

Eric

The jet settings are important but don't need to be the same in all 190 SLs. It is unlikely that your bogging down is the result of the jets. More likely the carb linkage may be out of adjustment by .002 or so. Have someone hold the accelerator pedal to the floor (I've cut a piece of 1x1 that wedges between the seat and the pedal) and verify that both carb throttles are against their stops. If not adjust them so they both hit the full throttle stop at the same time. Don't pay any attention to whether they both start to open from an idle at the same instant. Afterall you don't drive the car at idle. This should correct your bogging. I believe I'm using aircraft cable ends on my throttle links similar to you. It gets the slop out of the old ball & sockets and allows you to balance the carbs better.

I'll see if I can find my jet numbers. BTW I did drill out my acceleration jets from .44 to .52mm. That increased the accel jet flow by about 50%. It affects fuel mileage but I like the extra get up and go.

robby

[Robby Ackerman]

My carb specs using dual weber 40DCOE: choke size 30, aux venturi 4.5, main jet 1.15, emulsion tube F2, air corrector 2.00, idle jet .50 and acceleration jet .52. I'm using K&N air filters.

Robby

[bstreep]

Eric,

Here are mine, as well as those suggested by Gran (sp) at Pierce. He spends 3 days a week at the track working on NOTHING but Webers. Now, I do need to qualify this in saying that I'm still running rich and mpg sucks... If anyone has any ideas, let me know!

Main Jets: 115 (had 110s) 125
Emuls: F2 F11
Air Corr. 200 200
Idle Jets 45F9 50F9
Pump Jet 45 40
(says my 40 is better, but Robby likes his 52s!)

Robby, where did you get your air filters? I'm seriously thinking of removing the conversion kit for the stock silencer/filter and putting the smaller filters on the carbs. I'm tired of the intake leaks... I put the anti-vibration kit on, but I'm not sure I like it. It's difficult to torque down evenly and I'm not completely sure I don't have any leaks there as well. I'm going to try your "floor it" syncro method tonight.

[Robby Ackerman]

Bill S

I got my K&Ns from Advanced Performance Technology http://www.aptfast.com. I paid $121.16 plus 5.81 shipping for a pair of S/O 40mm by 2.5" filters including the brackets. I have three complete sets. One dirty in need of cleaning, one new set on the car and a new set in the box, never opened. You can get a set from APT though I wouldn't mind selling my 3rd set say for $100 plus shipping. It is complete EXCEPT for one gasket that fits between the carb and the filter base plate. I usually make mine own gaskets from stock gasket material. You may be able to shop around and find a better deal.

I find that my carbs run fine (not to rich) from 80 mph to 113 mph. Below that, yes they run rich. Re the acceleration jets ... after using the .52mm jets I installed my original .44mm jets drove around for a few days and, well gas mileage was better, but the larger jets spoiled me so the .52s went back in. I get 17 mpg in town and 17 mpg on the highway though I did get 22 mpg at a steady 80/85/90 across Montana, Wyoming and Nebraska...no traffic on the roads.

Robby

I've been reading about these webers quite a bit now and from what I have seen there are quite a lot of different combinations that will work in a car.

Robby: I have already tried setting my carbs so that they are in sync at full throttle with no luck. Actually the whole reason I made the new linkage was to fix this disparity. For your accelleration jetting you could try a stronger sping instead of a bigger jet, and also less air correction and a smaller main jet setting. This way it won't run rich at moderate speeds and not lean out as much at higher RPM's where the higher air flow starts to edge out the fuel in the mains. Less air correction will give you more fuel at all rpms but slightly more at higher RPMS.

I ordered some jets from Pierce Manifolds today and will start playing this weekend. My first step will be to fix the transition from idle jet circuit to the main jets....then look at the top end.


E

[Robby Ackerman]

Thanks for the jet tips.

Re the bogging. I'm not sure what to say without looking at the car. What plugs and what setting are you using? Bosch copper and ngks work well in the 190 SL. Platinum will not. I'm using ngk BP6ES set at .024". With the car idling, when you floor quickly, like stomp on it, does it rev up or shut off? From what you describe I expect it shuts off which it shouldn't do if EVERYTHING is just right. plug wires, do they show zero resistance? The plug ends do they have 1000 ohms resistance or 5000 ohms?

robby

[Robby Ackerman]

Thanks for the jet tips.

Re the bogging. I'm not sure what to say without looking at the car. What plugs and what setting are you using? Bosch copper and NGK work well in the 190 SL. Platinum will not. I'm using NGK BP6ES set at .024". With the car idling, when you floor quickly, like stomp on it, does it rev up or shut off? From what you describe I expect it shuts off which it shouldn't do if EVERYTHING is just right. plug wires, do they show zero resistance? The plug ends do they have 1000 ohms resistance or 5000 ohms?

Robby

Hi Robby,

It depends on what RPM I am at. If its between 800-2000rpms, it pretty much bogs and then after about 4 seconds takes off. Above that range it really gets moving, Which is why I think its short on the idle jets, accel pump jets, and maybe the just a little shy on the mains or not at all.

You wouldn't believe the previous carbs I had...42DCOE with 145 mains and 50F8 . Yeah it ran rich, but if you hit the gas off idle it would smoke the tire...no joke. But these carbs were very old, and the fuel float assembly was shot. I decided to get new ones instead of rebuilding them. I didn't have the flat before, but it ran really rich. I tried the recommend settings, but expect to end up somewhere in between .... maybe 55 idle jet and 125 mains....

I'm running NGK's set at .035 .... maybe that's too large a gap?

I dunno about the wires but will check them.

[Robby Ackerman]

Try the NGKs at .024 and see how it runs. Mine will NOT run at .035. If mine get above .030 it doesn't run right.

robby