Carburators, Weber 38 vs. Stock Carb? Q/A
Answer: I recently installed the 38 mm weber on my 76 Fj-40 I bought from man-a-free. It cost about $400 and came with adapters. I was able to retain the stock air cleaner and throttle linkage. My stock carb was in good shape before I changed it so I think it's fair comparison.
Advantages: I defiantly noticed a power increase, It accelerates better and I was able to keep up with traffic. It had the power it did when the 2F was bran new. I took it out to steep hills and climbed straight up till the rear wheels broke loose a couple of times and it ran fine- no flooding I’ve not had it long enough to determine mileage yet but I am expecting 15-16 hiaway as opposed to 12. It’s not permanent, If you don’t like it take it off and resale it.
Disadvantages: Not smog Legal, keep your old carb. I though the adapter kit furnished was quite poor, the instructions were not readable leaving you to guess and many of the fasteners were to short I expect the pot metal adapters to eventually crack and leak. I am normally at 2000 ft ,at about 5000 – 6000 ft. I noticed a decrease in power, I was still able to maintain 55m.p.h though. Probably a jetting issue. I’ll find out. You have to mangle you original throttle linkage bracket to get it to fit.
Be sure to disconnect your battery before you work on the fuel system.
Answer: Dave, I have been researching this issue considerably since I decided that there is no way I will be done restoring my '76 in time for Cruise Moab 2000 without cutting corners or quitting my day job...sooo
I'm taking my '71 which has the bad bad Holley. Okay, the Holley's fine as long as the trail isn't too steep. If you don't plan on offroading they have great power and decent mileage.
I have emailed with experts (Mark Whatley and Jim Chenoweth), and spoken with members of my club whom I consider to be experts. A couple of guys in my club run Weber 38s and love them. Side note, if you decide on a Weber, don't use the 32/36 as it is designed for the CFMs of a 4 cylinder, go with the 38/38 which is designed for a 6. A couple people in this forum also seem to really like their Webers.
According to Mark Whatley and Jim Chenoweth, the stock Aisin carb, when in good condition (read=rebuilt) and properly set up can't be beat. Not necessarily "better" than a new Weber, but at least as good as. They don't require any adaptation to the intake or air cleaner or linkage, and have a manual choke. The Weber is automatic, which I don't like. And I have not seen a kit for a new Weber 38 for less than about $380. CCOT sells rebuilt Aisins for $275, and if any of you have ever done business with them, you know their customer service can't be beat.
I have decided to go back to stock Aisin for my '71 for Cruise Moab 2000. Unfortunately, the PO of my cruiser who had the Holley installed, apparently didn't keep the old air cleaner stuff, so does anybody got an air cleaner hangin' around for a 3/71 FJ40 they'd like to sell me?
PS, a very warm thank you to everyone who has offered me their old Aisins, very much appreciated!