6cyl & carbs
Guess I'll chime in F/2F 6's, and carbs. First off, the stock Asian carb is a 38mm carb. Any thing smaller is not going to be adequate for a 2F. I believe the major differences of the carbs on F and 2F engines have to do with emission controls and the multitude of vacuum lines. And if the PO has "eliminated" some or all of these vacuum lines, looking for more performance, its just not going to run right. "Toyota Trails" has an excellent article on 2F carb and stock setup some years back. I don't know if this article has been archived, but I probably still have it somewhere. I'll look when I get back to Colorado Springs. As for the Weber you have, a 34/34, was probably for a 4 cylinder, but it should probably work, although, the performance envelope will be a little limited. It should have a minimum of vacuum lines, probably for a vacuum advance to the distributor. Jetting may be an issue, as is the float level, but these items, and what they should be, should be available on line or in the "book". Float level is somewhat simple in principle, in that too low will be lean, and too high too rich and prone to flooding. The stock Asian has a float glass that says to set the fuel level in the middle or something like that. That idea was probably great when in, say, 1972, regular was somewhat amber, and ethyl was somewhat red in color. From personal experience, on my '72 FJ40, the level is set somewhat low, and it runs fine, and doesn't flood out even at angles that exceed my personal fear factor. Fuel mileage is also some what consistent at 14mpg around town (just like a new one, but with no danger of the gas pedal sticking!) and all the way up to 16mpg on the highway) Mileage is higher with pure gas and a bit lower when they add the 10% alcohol. It is more difficult to diagnose conditions when the fuel is not pure gasoline too. If jetting is too lean, it will be struggling at WOT. If jetting has been set at a lower elevation, then it will be too rich at CS elevations and higher. Too rich give a blubbering sound, and is sluggish. If your only way to fix this is to lay out an inch high stack of $$, then there are other things to consider. If you can find a stock Asian, (remember, they have 38mm bores) and also, there a lot more good running stock set ups out there than there are Weber setups. Another idea for replacement could be a TBI setup for the 2F using a GM 4.3 throttle body and CPU with all the required sensors and wiring. Downey (which went belly up last July) used to have a complete kit for lotsa $$, or a throttle body adapter and wiring harness, which with your sensors & TB and hundreds of hours of time works quite well. There are also some Rochester 2 barrel setups out there, which do work, but I'm not sure how well. The Rochester's come off smaller GM V8's, like 265's, 283's 305's and so forth, but while the bolt pattern is close it isn't a fit as well as throttle linkage. Advantage is cheap and readily found. And then there is a proven fix which some advocate, is to transplant a SBC with either a quadrajet or TBI and go from there.
Carbs can and do work quite well.
I will be back in CS Thursday evening, and I'd be glad to take a look if you want.
Hope this helps.
Darryl
1972 FJ40 - F with stock carb & K&N & 3 into 2 into 1 header & 2 1/4 exhaust
TLCA 3911
N7EBS
Trevor was working that little 'runner and making it through some amazingly deep snow. Nice drivin' Tevor!
He's going to give me options tomorrow or Tuesday.
