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  #101  
Old 12-07-2012, 09:59 AM
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subzali subzali is offline
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You can do a search on MUD for instructions on how to tune these carbs for best idle. I should have that thread bookmarked but I don't yet. You really just need a vacuum gauge and a tachometer. To get the exact right jet settings you'll need the wide band.
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  #102  
Old 12-07-2012, 10:18 AM
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Thanks, but the only one of those photos I took is the one of me with the mask...

I have an automotive multimeter with a tach function. No vacuum gauge though (that was a borrowed piece of kit). And now that I think about it, without a selection of jets to swap around, a wide band doesn't actually do me a whole lot of good does it... Additionally, depending on the specific wide band setup it may not even be all that useful or accurate without a sensor bung in the header... Really didn't think that through...

Looking at SOR's site, it really doesn't look like there's much in the way of jets available for tuning even if I wanted to! Is that really the case, or is that just more fuel for the diesel swap fire?
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  #103  
Old 12-07-2012, 10:21 AM
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you can get some numbers by putting the sensor in the tail pipe. that is assuming you don't have any exhaust leaks. welding on a bung is best. I think i have a few spares.

I have a vacuum gauge too.
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  #104  
Old 12-07-2012, 10:32 AM
spectre6000 spectre6000 is offline
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Marco, wanna help a cruiser newb with a carb set up? That is, after I get the fuel pump situation taken care of, get the timing set and valves adjusted, get that vacuum leak tracked down and rectified, and get whatever else sorted out that crops up requiring sorting...

Speaking of, who is at what elevation running what jets in what carb with what engine? I have a 1.5F rock stock (though the jet set doesn't seem to be stock, nor does it make a whole lot of sense), and I've read through the various jetting threads on this and other forums, but there generally isn't enough information to be all that useful...

Also, where are people getting jets? I'm half tempted to run down to Jim's and buy all of his 2 barrel carb cores just for the jets... $25/each and could probably be talked down a bit if I bought a bunch of them...
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  #105  
Old 12-07-2012, 11:02 AM
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When I broke the carb down, it had 55/80 bleeds (I think I keep seeing these referred to as "slows"), 20/180 primary/secondary mains, and 55/114 in the plugs on reserve. I didn't take note of the accelerator pump/power jet for some reason...

That jetting setup strikes me on the surface as pretty messed up between the mains and the jets in the plugs. Having a larger main on reserve than in action when at altitude makes sense, but then the secondary has larger jets in action than on reserve... Never mind that neither of the double digit jets (55/20) make sense in context with what I'm seeing others run... I think they're power jets, but that doesn't make a whole lot of sense. Any ideas what was going on there? Am I the crazy one?

Presently I have the same 55/80 primary/secondary bleeds. 114/180 primary/secondary mains. I still didn't take note of what I had for the power/accelerator pump jet. Then I have 55 and 20 in the plugs...
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  #106  
Old 12-07-2012, 11:49 AM
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subzali subzali is offline
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I don't think you're the crazy one. Sounds like you put it back together a little more reasonably.

My '78 carb on my '77 2F has:
1st Main Jet: 136 (1.36mm)
2nd Main Jet: 171 (1.71mm)
1st Slow Jet: 75 (0.75mm)
2nd Slow Jet: 80 (0.80mm)
Power Valve: 80 (0.80mm)

From Moab to Argentine Pass it's never skipped a beat. Problem is it's hard to compare because every year just about was different. See here:
http://www.sor.com/sor/cat042d.tam

We had a discussion about jet sizes a couple years ago here:
http://risingsun4x4club.org/forum2/s...ad.php?t=15074

I'll try to find what Randy posted about what he used in the Blue Mule (1974 F.5 engine). Personally I'm not sure it's worth getting down to the gnat's a** on this because we're talking about tractor motors here, and because we change elevation so much. A typical trail run might have you changing 5,000 feet of elevation or more in a day. I might play with mine a bit but honestly it runs fine the way it is and the plugs are fine, even with a different model year carb on it.

Okay, check out this post too from Randy and Ricardo:
http://risingsun4x4club.org/forum2/s...jet#post175380
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  #107  
Old 12-07-2012, 11:57 AM
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subzali subzali is offline
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What's the build date code on your carb, too, for reference? It's a series of numbers, a letter, and numbers stamped on the top of the air horn, near the front.
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1977 FJ40 2F "Brahma" + Lockright, tach, Warn 8274, FJ60 Power Steering, soon to lose the Sanden OBA to go back to factory emissions
1996 FZJ80 1FZ-FE factory lockers + Safari Turbo , CDL switch, cup holder, AATLAS1X leather, heated seats and JDM switches
2000 Tundra Limited TRD 2UZ-FE SOLD
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  #108  
Old 12-07-2012, 12:15 PM
spectre6000 spectre6000 is offline
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At least I'm not the crazy one. I'm guessing the plug spares are power jets... Weird.

It's November 8th, 1973.

A little slightly off topic update: new fuel pump in. Wrong inlet drilled, runs it right into the oil filter mount. Off to go see what I can find in the way of an angled fitting... It's always something. Ugh...


Look! I made a photo!
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  #109  
Old 12-07-2012, 12:26 PM
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RicardoJM RicardoJM is offline
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Quote:
Originally Posted by spectre6000 View Post
... A little slightly off topic update: new fuel pump in. Wrong inlet drilled, runs it right into the oil filter mount. Off to go see what I can find in the way of an angled fitting... It's always something. Ugh...

Look! I made a photo!
Move the one over from your old pump.
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  #110  
Old 12-07-2012, 12:31 PM
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RicardoJM RicardoJM is offline
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I'm trying to keep up with the thread and it sounds like you are on the right path. A very useful item for you would be the F Engine Manual. I have one in PDF version that is just under 50k, shoot me your email address.

Chapter 2 of the FSM is dedicated to Engine Tune up and the following snippets of specifications are something I have not seen you have yet.
Distributor - point gap to .016" ~ .020"
Dwell - did not find it noted
Timing - BB to pointer is 7 DBTC, you engine will likely run best with more advance.
Plugs gapped to .028" ~ 0.031"
Valves .014" on Exhaust .008" on Intake
Idle RPM 650-700, High Idle did not find but IIRC it is 1800
Compression - 150 at sea level - need to adjust for altitude
The carb tuning process is pretty straight forward. This link describes in pretty well. The goal is obtaining the highest vaccum from the engine at idle by adjusting idle mixture, RPM and timing. I've got all the equipment and can also give you a hand when you sort out the fuel issues.

Regarding jets, I have not found a source to by new jets. Pulling carb jets from Aisan carbs will not always work. In the DD38 carb, the primary jet sizes are very different size from what you would pull out of other Aisan carbs - been there done that. The FSM has a chart indicating that these came from the factory with the following jets.
112 Primary in the carb and 108 in the plug
200 Secondary in the carb
090 Power jet in the carb and 080 in the plug
The FSM is mum about slow jet sizes and indicates the need to reference another document (I've never found it) for USA details and it also indicates that at atlitudes above 6,600 feet the 108 should be in the primary and the 080 should be in the power jet.

All that said, I am running the following jets for my F.5 engine:
114 - Primary
180 - Secondary
60 - Power valve
50 - in both slow jets
I've tried 112, 116, 118 in the Primary and my "sweet" jet is 114. The jets work just fine everywhere I drive. Perhaps at high altitude I may be running just a tad rich, but I'm not driving at 10K+ feet often enough to be concerned.

If I'm tracking correctly, you installed the following jets in your rebuild:
114 - Primary
180 - Secondary
UNK - Power Valve
55 - Slow Jet
80 - Slow Jet
The 20 jet does sound confusing, but I think under the scrutiny of a magnafying glass it will be a 200. The 55 is consistent with the size of a power valve jet.

The most difficult jets to find are Primary and Secondary; and on those I think you are in good shape. I'm pretty sure I will have a smaller slow jet to replace the 80. In my research, the Power Valve jet is not as critical for tuning. IIRC at some point I read JimC indicate you cannot get too big on the Power Valve. I did rebuild a DD38 that was missing the Power Valve and while the carb did need to be rebuilt (varnish build up from lack of use) the owner indicated that it ran great prior to getting the varnish build up from lack of use.
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