Weber carb

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Me again. Got the 78 running. Installed new plastic tank yesterday. Went ok. Crawling around on gravel underneath it is hard on my 67 year old carcass. Should have it driveable next weekend. Get it in the garage and on the lift. We really want this fj to be a primary car and plan on spiffing it up. Anyway, question today is on carbs. It’s completely stock now. Is there a benefit of going to a Weber carb setup. I’ve read yay and nay. Read the Weber isn’t as good on rough or steep roads. Floods out. We have lots of both. Anyway fellers, opinions?
 
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I got a rebuild kit from mikes. Plan on overhauling it next weekend. Surprisingly it runs fairly good now. Was looking at the future for maybe a few more hp. Used to use Weber’s on vw’s years ago and they were really good for instantly more hp. The little progressive 2 barrels worked really well on bajas and rails. But like I said I’ve read some negative stuff about using them on fj’s. Flooding on long hills and bumpy roads etc. I’ll stick with stock. Are there any other bolt on things a guy can do do to increase performance? Particularly on the highway, that won’t screw up off-road ability? Don’t plan on mint 400 kinda stuff. But want to use it on the mountain roads around here and still cruise on the pavement. We live at 6500 elev and there is a lot of 10,000 elev here too.
 
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They make Weber conversions specifically for fj40’s. Was wondering about folks’ experience with them. I’ve read a few comments elsewhere. Mostly it seemed they work ok if you are really good at tuning them. Just wondering about experience others had. I had a 67 for a long time. Loved it. Cast iron stock carb weighed about 100 pounds. Seems like it was up draft. Worked really well on all types of roads.
 
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I started out on a gravel driveway, about twenty years ago, cardboard helps.

I just installed a 2F OEM carb from City Racer. I live at 6,800-feet. I'm happy. The OEM '75 carb would stall immediately after starting, now it it in good shape. Rebuilding a carb might get you 90% there, as it did for me. Now, I'm running a 138 primary jet, instead of the 144 that came with the '75, and I no longer have a lean symptom as bad on a cold motor. Running headers, so it probably isn't that good in the winter. But the new Aisan carb was well worth the money. Only problem is the original choke cable protrudes too far, and I don't want to cut it.

I'm a big fan of Weber on my Nissan. The design of the Aisan is a bit funky in the air horn. The Weber's air horn isn't a crazy pathway for the air to flow with major hardware considerations for mounting the venturis. The Weber's pump jet doesn't spray all over the air horn, and into the early EGR tube, it goes right to the opening at the throttle plate. The electric-choke Weber options offer the only new throttle positioner diaphragm, which is good for people who don't know much about carburetors, and manual chokes (average mechanics, family, fuel-injected folks, etc). My two '75 throttle positioner diaphragms are minor vac leaks with no easy fix. The '75 carbs have minor vacuum leaks on the power valves, again no easy fix. My motor has low vac and compression. Running the non-USA Aisan choke, and the OEM '75 choke, creates a lean symptom at medium throttle when cold. But, I'm just going to install a hand-throttle for the accelerator pedal, and call it good.

I ran a DGEV for an afternoon on my 40. It was super responsive. It lacked on the highway, in a lean way. I was thinking of a 38/38. I bought a 38/38 DGS-manual choke. The choke requires a different set-up than the DGV on my Nissan, so I never got anywhere with it before winter. This spring, I learned that City Racer was offering an affordable non-USA, OEM carb. It comes with two jet options. He also offers the made-in-Japan clone. I'd go with the made-in-Japan if I was a gambling type or low on carb funds.

What is your vacuum at idle?
What is your average compression?
Do you have vacuum advance on the distributor?
Do your plugs stay kinda clean after running it for a while?
Are you sure that your brake booster and all other vacuum components are up to speed?
 

brian

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They make Weber conversions specifically for fj40’s. Was wondering about folks’ experience with them. I’ve read a few comments elsewhere. Mostly it seemed they work ok if you are really good at tuning them. Just wondering about experience others had. I had a 67 for a long time. Loved it. Cast iron stock carb weighed about 100 pounds. Seems like it was up draft. Worked really well on all types of roads.

yes i know, i was a fan boy for many years till i saw the light
 
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Lots of info dizzy. Thanks. I’ve only started it a couple times for a few minutes. Haven’t done any diagnostics on it. It’s a stock 78. Are they vac advance? Been busy with rat nests, cleanup and a new fuel tank. Goal is to get it driveable next weekend, get it in the garage where I have a lift, air and tools and get serious about things. Just looking to the future. Like I’ve said, want it to be a jump in and start it and take off wherever we want kinda vehicle. Plan on a complete fixup front to back. Lift, paint, interior, all them things. I’ve thought about the new oem carb thing. See how the rebuild goes.
 

hobbes

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Weber Sarge has lots of good information in the thread below. I went from 8 mpg with my Weber to 13-14 mpg with a rebuilt stock carb. This issue with the Weber’s, I believe, is while there are conversions for the FJ40, there was never a carb designed for the FJ40. Big difference.

 

Zjohnsonua

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Ran a weber 38 on my 60 for 40k miles before an engine swap. I wheeled the crap out of it as well. No problems on steep grades.. They run well so long as you tune them to do so. There is not a one size fits all weber. You'll need to rejet when you make big altitude changes, but otherwise I never had much problem out of mine. The only hitch to em is getting the fuel pressure correct. You cannot get away with the factory pump without letting some of that pressure bleed off - I believe this is the root of most ex-weber owner hate. 3psi is tops for the weber....after that the bowl overflows and all bets are off for tuning. There are a few ways of solving that problem.
 

Hugh Heifer

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I had frequent vacuum leaks with my weber. It was my experience they tend to run rich but necessary for them to do so in order to get the 2F to seem to be happy under them. I was never able to dial in my electric choke either. I did add a fuel pressure regulator as well.
I ran a weber for a while on a VW years ago too but then swapped back to a later oem and drilled the jets out to get myself a bit more out of it. (34 pict 3 maybe - it has been 35 years).
Others have gotten significantly better performance out of Webers but it was easier for me to swap to a Trollhole to match my non-USA dizzy with Pertronix. I was very happy with that set up.
 
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Rebuilding a '73 carb was a sublime experience, for me. Sold the truck. Decade plus later, got another. Couldn't wait to rip into the carb. Something surreal. Maybe it is the passiveness that is required of its surgical-precision like operation, or when the F/2F finally wakes up, and you breathe a little life in your Frankenstein. If nothing else, you get a little buzz from some volatile hydrocarbons. Either way, tools and parts are almost more valuable to me than the actual truck, gives me purpose, wards off the insanity from the everyday grind.
 
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Thanks for all the information. I’ll stick with stock for now. Runs for sitting over 15 years. After a carb clean and overhaul it should be better. After I get it highway ready I’ll decide on what to do.
 

hobbes

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Several people on here offer carb rebuilding services. Or do a YouTube search for Pinhead’s how-to video if you want to tackle it yourself.

For the record, my Weber ran great once I got it dialed in. But so does my OEM carb now, which I much prefer. If I were to look away from OEM, I’d look towards the new fuel injection stuff not a Weber. YRMV....
 

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