The procedure in the link seems to be sealing off the bowl vent connection between the float bowl and the air horn, then rerouting it externally. Eliminating this feature will make the carb susceptable to air fuel ratio changes as the air filter gets dirty. The internal bowl vent keeps the air pressure above the fuel the same as that in the air horn, which won't vary as a ratio when the air filter gets plugged a bit. The equal pressure keeps the jets feeding fuel at the same relative rate regardless the filter restriction.

A better solution may be to find a way to raise the vent inside the air horn.

Anyone ever able to get a 32/36 Weber to fit the stock air cleaner housing?

It would just involve using the bottom air cleaner plate that comes with the Weber and making a round shape out of it to fit the stock air filter housing base on the top. You'd also have to have a center stud so the wing nut could go back on. I don't think I've seen it done.

Alternatively, you could cut the bottom of the stock air filter canister to the shape of the Weber's top. Haven't seen that, either.

Would be a good mod, though.

John B.

Maybe welding the base from the weber air cleaner to the stock housing would work, too. That way more of the stock emissions crap would reconnect. Some smog techs are lazy and might not notice the swap if it physically passes the emissions tailpipe standards and it "looks" stock!!! <img src="/forums/images/graemlins/nana.gif" alt="" />

http://www.carburetion.com/after.htm

On the left hand side, click on "conversion carbs", then next to the Redline box, do a Weber search for Mitsubishi. The kit # I got was K614, which is the DFEV Weber carb, for a manual trans. I think the kit # is the same for an automatic.

An annoying problem has developed with this Weber. This carb does not appear to have any kind of throttle return spring, so I'm not sure what force is acting on the throttle linkage to close it. What's happening is the linkage doesn't seem to be fully closing down to idle speed, so when I'm slowing down, the idle will sometimes stick anywhere from 1000 - 2000 rpms. A quick blip of the gas pedal will get it to return back down to 800 rpms, but it's annoying. I've adjusted the tension on the throttle cable itself, and there's enough slack in the linkage that I don't think it's the cable, especially since when I blip the gas pedal the idle drops down to where it's supposed to be.

The stock Mikuni has a throttle linkage return spring on it, so I figured it couldn't hurt to try and put one on the Weber. I found a threaded hole on the intake manifold, towards the back, and put a bolt in there with a spring that goes up to the Weber throttle linkage. A friend of mine is out driving the Monty, so she's the guinea pig to see if this spring is going to work.

When I was at the hardware store looking for a spring, I had to keep in mind that it had to have enough tension on it to close the throttle linkage, but not so much that it would make it difficult to open. I'm not so concerned about WOT operation, since it most likely will hardly ever see that. The 90 percent solution for daily driving is what I'm going for here. I'll try and post a pic later, but I'm keeping my fingers crossed that this will work.

UDPATE - looks like the spring trick worked. The rpms dropped down like they were supposed to every time, no need to blip the gas pedal, had a nice steady idle around 800 rpms.

This pic shows the spring runnning from the throttle linkage down to the bolt on the intake manifold. The head of the bolt is barely visible around the 6 o'clock position, below the "C" in the Gates Corporation wording on that large black rubber hose:


This pic shows where the spring is attached on the throttle linkage itself. Instead of hooking it in the same cradle where the throttle cable goes, I just put it around the arm that goes into the linkage:

Just wanted to pass along an update. The last thing I did was add that throttle return spring, and I've gone thru a tank of gas where I wasn't messing around with the settings on the Weber.

Pleasantly surprised at the increase in mpg I'm seeing now. Before, with the non-working secondaries on the Mikuni, I was averaging less than 15 mpg. Now, with the Weber, my first tank went almost 20 mpg. That's a significant increase in mpg, not to mention daily driveability, especially with that return spring installed.

Next thing to look into is this rattling sound coming from the carb whenever it's started, and that's whether it's cold or warm. I think it's related to those butterfly plates on the top, and the linkage to them on the side of the carb. From what I can tell, they look to be connected to some kind of "cam" gear looking thing on the side, with an adjustable screw that looks like it's supposed to touch it. Well, in it's current setting, that screw isn't coming anywhere near touching the cam, so I think those butterfly plates are pretty much wide open at start up.

I can live with the rattling noise at startup for now, since it goes away within a couple of minutes. But when I'm feeling frosty, maybe I'll remove the air cleaner so I can see those plates, fire it up, see where the noise is coming from, and figure out what to do next.

But I'm really liking how it runs now, and 20 mpg is an added plus!

Generally, the butterfly plates in the top of a carb are the air-restrictors for the choke system. If it's cold then these should be nearly closed. Come winter you may have to adjust this..

http://www.explainthatstuff.com/how-carburetors-work.html
http://www.thecarburetorshop.com/Automaticchokes.htm

"Next thing to look into is this rattling sound coming from the carb whenever it's started, and that's whether it's cold or warm. I think it's related to those butterfly plates on the top, and the linkage to them on the side of the carb. From what I can tell, they look to be connected to some kind of "cam" gear looking thing on the side, with an adjustable screw that looks like it's supposed to touch it. Well, in it's current setting, that screw isn't coming anywhere near touching the cam, so I think those butterfly plates are pretty much wide open at start up. "

Thanks for the links. Made me think of something else. The Weber has an electric choke, and I found the colored wire (red/silver?) that went to the choke on the Mikuni. I followed the wire to the harness, and stripped the end of the Weber wire and just shoved it into the female end of the harness where the red/silver wire was. I didn't check this point with a test light, to make sure it was getting power when the key was turned on. That might be my problem, in that the Weber electric choke isn't working.

So I'll break out my test light tomorrow, and make sure that connection is getting power when the key is turned on. If not, I'll find one in the harness that does, hook it up there, and see if the rattling noise goes away.

Well, I was 50% successful, lol. I used my test light and multimeter to test the harness where the stock Mikuni plugged in to, and low and behold, there were only two plugs that had any power when the key was turned on, and neither of them was where I had the electric choke wire for the Weber. If you point the plug towards the engine, the two spots that had power were the two on the far right, upper row. I had the Weber choke wired into a plug on the lower row, second from the left.

As I said, the choke wire on the Mikuni appeared to be red/silver, but that connection on the harness does not have power. I looked at a writeup someone did on swapping an SQ engine into a D50 (more or less same as the Monty), and it looked like there were at least two sources in the harness that should have juice when the key is turned.

So I used my test light and found two in the harness that lit up when the key was turned, and confirmed this by using the multimeter. I plugged in the Weber electric choke wire into one of these plugs (far right, upper row), and now that arm engages the cam thing I talked about earlier.

However, the "rattling" sound hasn't gone away, so it looks like I'll have to pull the air cleaner off and see what's going on with those butterfly plates at startup. Another thing I noticed is now that the choke is apparently working, it's a little harder to start and hold an idle. But as before, once the rattling noise goes away in a couple of minutes, it settles into an idle right around 800 rpms, and seems to be working fine, like before.

I'll have to put a few more miles on it, now that the Weber electric choke is powered, and see if I notice any difference, either in driveability or mpg. I'll post any updates as needed. I still think buying this Weber was more than worth it, because of the results I got in driveability and mpg. I just hope I don't get back to CA any time soon, because I'm almost certain that it won't pass smog. But for now, I'll enjoy the heck out of driving it here in the smog-test free great commonwealth of southeast VA, lol...

Since the "rattling" sound goes away once the engine warms up this means the mechanism for the choke is most likely the culprit. All chokes need to be adjusted, even your type. My guess since it also runs rough cold the choke may be set to hard so that the linkage is pushing them to much in the closed position. With the motor cold & off loosen the three screws on the choke assembly and turn the cap until the butterflys just start to open then back it off a tad. (see link below)

Just a question... do you hear the rattling when the breeather is off also? Could it be that's making the rattling? Does your new carb have the same radius opening as your old one? If it's smaller than you might have a gap.




Setting Choke: The choke is adjusted, by loosening the three screws on its ôring,ö then
rotating the choke clockwise for less choke, and counter-clockwise for more choke.
Note: The Fast Idle Speed screw is located behind the choke itself, and can be adjusted
to increase or decrease the fast idle rpm.

http://www.cjclub.co.il/files/Weber3236adjust.pdf