Weber 32/36 conversion / Q? need to re-jet?? (1 Viewer)

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Searched all Weber related posts but my issue not directly addressed.
Just finishing up and driving daily now a multi year frame off restoration : 1966 FJ45 ( BC truck for its whole history) / freshly rebuilt F engine/ tranny/transfer case/ all running gear/ ADDED: front GM Monte Carlo discs ( JTO) and rebuilt rear drum systems and added mid 70’s AISIN dual circuit 7/8” master and booster ( much angst getting the brake system tuned and working...different post); electronic ignition (HEI...works well; power steering ; redone interior; body off paint job.......in short, THE WORKS
ALSO CONVERTED to WEBER 32/36 ( Man A Fre I think?....supposed jetted for F/2F engine). Followed WEBER initial set up instructions WRT mixture screw ( 2 turns out initially and ear tune from there...
Also timing set and checked twice ( timing light / per FSM 7 BTDC). Also ...no vacuum leaks...all new vacuum , fuel lines.

THE ISSUE: truck runs great on primary Weber circuit but falters, occasional backfire with pedal to the metal ( ie secondary fuel circuit kicked in. Difficult to get over 60 mph ( not that that’s where I want to cruise but need to get carb issues sorted out so that I could....).

THE QUESTION: appears truck floods when secondary fuel circuit kicks in. There appears to be no WEBER 32/36 adjustment for secondary circuit except changing jets ( smaller in this case?). Other avenues to pursue or should I be re-jetting smaller?
1607909213392.jpeg
 
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I have a 76 with a Weber 32/36 and DUI (hei). My electronic ignition recommended advancing the timing beyond the 7* OEM setting. I settled in at 11 degrees I think. This helped the stumble when mashing the gas. It didn’t entirely fix it. I still have a hesitation when I floor it. From what I’ve read the 32/36 is under sized for my 2f. I’m told the 38/38 is a better fit. I’m happy with the current situation where I am measured in my application of throttle. Hopefully Sarge chimes in here. He, and a couple others are real pros when it comes to tuning a Weber and they’ll steer you right!
 

brian

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dump the weber, it's already to low of a cfm.
non usa oe carb for the win....i was a big fan of the webers, but its really a night a day difference between them, with the non usa carb being so much better then the weber....and that was with 38/38s, they are generally thought of as being small for a 2F.
 
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I have a 76 with a Weber 32/36 and DUI (hei). My electronic ignition recommended advancing the timing beyond the 7* OEM setting. I settled in at 11 degrees I think. This helped the stumble when mashing the gas. It didn’t entirely fix it. I still have a hesitation when I floor it. From what I’ve read the 32/36 is under sized for my 2f. I’m told the 38/38 is a better fit. I’m happy with the current situation where I am measured in my application of throttle. Hopefully Sarge chimes in here. He, and a couple others are real pros when it comes to tuning a Weber and they’ll steer you right!
Well now thats interesting and easy to try...thx! I have 7 degrees BTDC marked with paint marker on flywheel but now to find 11 degrees BTDC!!? And which way to rotate dizzy to get there?
Will report back.
 
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dump the weber, it's already to low of a cfm.
non usa oe carb for the win....i was a big fan of the webers, but its really a night a day difference between them, with the non usa carb being so much better then the weber....and that was with 38/38s, they are generally thought of as being small for a 2F.
WEBER 32/38 is rated at 240CFM ( rather a low volume carb).I’m not sure how that compares to the OEM AISIN carb that would have come with my 1966 FJ45 ( original carb is long gone....) which is what I think you are recommending? I did not go OEM carb and air cleaner as they would not allow addition of a dual circuit master cylinder nor brake booster....both of which I wanted/ needed.
The WEBER 32/36 that I’m struggling with allows fitment of new master and booster.
So....in short, I’m stuck with the WEBER and need tuning advice to get it to run right.
 
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There’s a Mud member named Weber Sarge As his name suggests he is well versed in tuning Webers. I expect you’ll need a kit with the full range of jet options so that you can get it tuned.
I am happy with my 32/36 but it’s not perfect. It starts easy, even when it’s hot
I can keep up at freeway speed 70-75 with my 2F-4 speed-DUI-Headers.
The compromise is that I can’t just mash the throttle. When I do the engine falters for a moment and then roars to life. I haven’t been able to eliminate that hiccup. So when I drive I have to moderate the speed with which I press the gas pedal. If i push it medium speed to the floor it keeps up and accelerates nicely.
 
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Well now thats interesting and easy to try...thx! I have 7 degrees BTDC marked with paint marker on flywheel but now to find 11 degrees BTDC!!? And which way to rotate dizzy to get there?
Will report back.
turn the distributor counterclockwise to advance. No need to re-Mark the fly wheel. Just advance it until you 7* mark is at the edge of the viewing window. Then take it for a drive. See if it’s better or worse.
 
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3_puppies

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I don't think you ever said what engine is in the rig? can't tell from the 1 pic, there are several versions of the F engine
 
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I don't think you ever said what engine is in the rig? can't tell from the 1 pic, there are several versions of the F engine
Will cross check engine SN with FSM and advise. In meantime engine SN : F276507
I don't think you ever said what engine is in the rig? can't tell from the 1 pic, there are several versions of the F engine
engine SN F276507 / SOR Engine SN a look up doesn’t go back further than 1969....so it’s a pre-1969 engine. FRAME SN FJ45-22080....similarly, SOR frame SN look up indicate Feb 1965. Actual registration says 1966.
 

Dizzy

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@firefighterjed You might try to drill-out your accelerator pump jet? They make different sizes for the 38/38, but I didn't see one for the 32/36. It will give you a richer pedal mash.

I ran a 32/36 for like one afternoon. I set it up with the stop on the secondary to be open at idle. The truck never had such a good low-end throttle response, but it was way too lean on the highway, I'm going to play around with the 38/38, or a Rochester, sometime soon.

Problems with the Aisan is that there is so much bs going on with the way the venturis are set in the air horn, that you can't get air thru the carb if the vacuum on the engine is low, having that shelf for the screws is just silly, and it seems to make the main circuit run lean. That, and the pump jet sprays gas on the throat of the carb, not at the sweet spot above the throttle plate. Now, a fresh engine rebuild would fix my vacuum problem, but I'd rather just dial the carb in, if possible. However, I realize that a vacuum problem can't be fixed by tinkering with a carb, but, I probably wouldn't have these problems if it wasn't so cold, and being up at a high altitude.
 

Steamer

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And which way to rotate dizzy to get there?

You can picture this in your head. The firing order is 1-5-3-6-2-4. If your distributor cap is not marked with the numbers, you can look at the ignition wire pattern and see that the rotor must rotate clockwise. Therefore, to advance the timing, you rotate the distributor body counterclockwise. When you rotate the dizzy, the rotor does not move, but the dizzy body & cap do.
 
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It will be difficult to find somebody with your similar setup. See what jets are available and you can drill out jets to make them bigger of course. I would also recommend getting an air/fuel ratio gauge installed so that you can monitor and tune by actual air fuel ratio and not by ear. A dude on YouTube, Thunderhead 289 I believe, has a bunch of carb tuning videos using timing/vacuum and air/fuel ratio that would be worth your time to watch. Good luck.
 
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I have a 32/36 in my 81 and dont have any issues at all. My has auto choke...It may be slightly underperforming, but I dont really notice it. As far as the issues posted above, I am not experience these. It cranks fine when cold after two pumps. I can mash the pedal without any hesitations and highway speeds at 70 are trouble free.

Unfortunately I cant answer the specific questions as my mechanic set it up for me, but I know he changed out the jets. The only real issue I have is that my truck has factory AC and the carb doesnt have an idle up solenoid which is a pain in the summer as the compressor kicks off at red lights due to idle rpm. Ive gotten used to feathering the accelerator pedal at stops so its now 2nd nature, but I would like to eventually address this.

The carb was installed by previous owner... I do want to swap it out eventually with a OEM carb. Its on the top of my list, but the list is long so it won't be anytime soon. All that being said...if I needed a new carb, I wouldn't install a 32/36.
 
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FIREFIGHTERJED:
Followed your advice and advanced ( NB rotate dizzy COUNTERCLOCKWISE to advance) timing from FSM recommended 7 degrees BTDC to approx 11-12 degrees. PROBLEM SOLVED ( well almost): pulls hard even when pedal to the metal / no stumbling/no backfires.
Thanks so much for that great tip....a much simpler fix than trial and error re-jetting ( although I think I will try that as well to see if I can get a little more performance and smoother acceleration)
 
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It will be difficult to find somebody with your similar setup. See what jets are available and you can drill out jets to make them bigger of course. I would also recommend getting an air/fuel ratio gauge installed so that you can monitor and tune by actual air fuel ratio and not by ear. A dude on YouTube, Thunderhead 289 I believe, has a bunch of carb tuning videos using timing/vacuum and air/fuel ratio that would be worth your time to watch. Good luck.
Air/ fuel ratio gauge / monitor a good idea....on it thx.
 

Dizzy

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If the stumble was a lean one - a broken-up flame front, and getting the spark started earlier on the compression stroke, some sources say that it will result in exhaust valve erosion (lowering compression), detonation/pre-ignition from hot glowing surfaces, and rapid wear on the spark plugs. For me, it resulted in harder starts, as the starter is working against pressure building up. But, four or five degrees probably isn't that much on static timing.

Swapping Weber jets is super easy. It can be done without pulling the carb from the manifold, just an air cleaner, the choke linkage, and the six screws that hold the air horn.
 

Dizzy

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It looks like you have a vac line running to the distributor? What is the setting on the idle speed screw? If it is much more than 1.5 turns in, then the port gets vacuum. Did you time it with the vac line disconnected?
 
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It looks like you have a vac line running to the distributor? What is the setting on the idle speed screw? If it is much more than 1.5 turns in, then the port gets vacuum. Did you time it with the vac line disconnected?
Yes, vacuum line disconnected / plugged and idle screw 2 turns out and not engaging at that point.
 
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It isn’t clear why you would think that the carb was “flooding” the engine. The symptoms are consistent with a lean condition and the circumstances, like a wide open throttle with no choke applied are inconsistent with flooding.
 

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