I have an FJ40 that had an Aisin 2 barrel put on it in 05 (i think it was a 1 barrel stock). It has been moved from Arizona to Denver and I have been told it needs to be re-jetted because it runs too rich. Does anyone know how I can get the jets / if I should just replace the carb with something else?
FJ40 Aisin Jets
- Thread starter terramei
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You should not replace the carb with something else.
I'll let someone who lives more than 20' above sea level speak to the jet size.
And FYI, the carb is an Aisan, not Aisin. Different companies-often confused.
Oh yeah, welcome to Mud. You got pics of this FJ40?
I'll let someone who lives more than 20' above sea level speak to the jet size.
And FYI, the carb is an Aisan, not Aisin. Different companies-often confused.
Oh yeah, welcome to Mud. You got pics of this FJ40?
I just moved to Denver a few months ago...used to live about 12' above sea level.
Alls I did with my carb was adjust the idle mixture screw.
Might help if we knew what year engine you're running...
Last time I needed a certain jet, I got them from the dealer.
Alls I did with my carb was adjust the idle mixture screw.
Might help if we knew what year engine you're running...
Last time I needed a certain jet, I got them from the dealer.
got parts numbers, Pighead ?
I just want to have some high altitude jets handy . . . one of these days, CO is going to be in the plans
I just want to have some high altitude jets handy . . . one of these days, CO is going to be in the plans
No, of course not...alls I remember is that the jets all started with the same digits, the last few digits matched the size of the jet.
And you might already have the high altitude jets in your float bowl plugs.
I can't help you on what jets will make it run best, but these are the part numbers for the 72:
21251 JET, 1ST MAIN
21251‑60200 ID=1.12 1 $5.85
90999‑41118 ID=1.18 1 $7.08
90999‑41120 ID=1.20 1 $7.39
21252 JET, 1ST MAIN SPARE
21251‑31013 ID=1.08 1 $4.63
90999‑41114 ID=1.14 1 $7.12
21253 JET, 2ND MAIN
21253‑60200 ID=2.00 1 $5.85
90999‑42180 ID=1.80 1 $7.12
21251 JET, 1ST MAIN
21251‑60200 ID=1.12 1 $5.85
90999‑41118 ID=1.18 1 $7.08
90999‑41120 ID=1.20 1 $7.39
21252 JET, 1ST MAIN SPARE
21251‑31013 ID=1.08 1 $4.63
90999‑41114 ID=1.14 1 $7.12
21253 JET, 2ND MAIN
21253‑60200 ID=2.00 1 $5.85
90999‑42180 ID=1.80 1 $7.12
And where do you find/buy jets?
SOR lists a bunch of discontinued...
Toyota is a no go...
Mark's Off Road?
SOR lists a bunch of discontinued...
Toyota is a no go...
Mark's Off Road?
You sometimes can find jets on the inside of your carb float bowl plugs...
Some carb rebuild kits used to come with new jets. Don't know if they still do, or if they are even the jets you want. Mark A. might be a good call, Kurt usually has a good selection of rebuild kits and maybe can tell you if jets are included...I hear Jim C. even sometimes sells parts out the backdoor of his shed.
77mustard40
SILVER Star
Last year I bought a Keyster Kit from siriuscoinc.com and it came with std and high alt jets for my 76
You may not need to reject, depending on the carb and your elevation in Colorado. I would recommend it, but some have had luck with sea level jetting here in the Denver metro area.
I'd drive it for a week or two and check the plugs (assuming it passes emissions as-is).
I'd drive it for a week or two and check the plugs (assuming it passes emissions as-is).
Running with sea level jets will cause it to run rich. Running rich will mean poor performance, potentially higher operating temperatures, and depending on the year of the vehicle and which county the OP lives in could cause emissions testing failure. It's best to "pay the money, cry once" (I've been using that quote a lot lately), and do it right. It'll run better and burn less gas. If set up correctly, you'll actually get better gas mileage at altitude than at sea level.
Well, if the OP had a 1-barrel as stock, he's not going to run into emission problems...so let's leave that out of it.
Sure, you may be running a bit rich at 5K feet with the sea-level jetting, but LandCruisers seem to tolerate rich better than they do lean. I thought that lean made an engine run hot, not the other way around. I've been running my sea-level 8 year-old Jim C. rebuilt 8/'73 carb since I got to Denver back in April. Like I said earlier, I turned in the idle mixture screw a bit, re-timed and drove it. I have taken it up into the hills for a few runs and have had no problems. It takes freeway hills like a dog, but I'm used to that. It still spanks the trails. I read that the stock jets are good up to 7k feet. But, since we're closer to 7K than to sea level, and I have a carb apart on the bench, I am thinking about how to maybe lean it out just a bit and see what happens. I do also disagree with "cry once..." a carb is meant to be taken apart and put back together many times. Meant to be fine-tuned to fit one's engine and environs. It's OK to take a few tries to get it set up correctly, and, even then, is subject to change. my 'plugs look just fine BTW.
Each time I rebuild a carb, it get a little easier and I learn a little something more about it.
Sure, you may be running a bit rich at 5K feet with the sea-level jetting, but LandCruisers seem to tolerate rich better than they do lean. I thought that lean made an engine run hot, not the other way around. I've been running my sea-level 8 year-old Jim C. rebuilt 8/'73 carb since I got to Denver back in April. Like I said earlier, I turned in the idle mixture screw a bit, re-timed and drove it. I have taken it up into the hills for a few runs and have had no problems. It takes freeway hills like a dog, but I'm used to that. It still spanks the trails. I read that the stock jets are good up to 7k feet. But, since we're closer to 7K than to sea level, and I have a carb apart on the bench, I am thinking about how to maybe lean it out just a bit and see what happens. I do also disagree with "cry once..." a carb is meant to be taken apart and put back together many times. Meant to be fine-tuned to fit one's engine and environs. It's OK to take a few tries to get it set up correctly, and, even then, is subject to change. my 'plugs look just fine BTW.
Each time I rebuild a carb, it get a little easier and I learn a little something more about it.
1911
chupacabra
I've run my 1980 with the stock sea-level jets (and with the HAC system intact) up to 13,000' and it did just fine.
A little rich will have a cooling effect, but too rich gets hot again (I want to say it generally starts getting hotter around 15:1, but I'm not sure on this particular engine). It'll run well enough, but it would run better (like it's supposed to) with a proper tune. It's the difference between going up a grade in 4th no the highway and having to downshift and go slower than traffic (more so than usual). Do it or don't, it's your rig. I'll be jetting mine for the altitude and enjoying all of my ponies and torques.
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Too rich gets hot?
So it is your opinion that peak EGT does not occur just lean of 15, dropping off in either direction until too far off stoich to run?
Please cite references or printouts from dyno runs.
As for jetting, bear in mind that the jets recommended by the factory in 1970-whatever were calibrated with leaded gasoline as fuel. Modern RFG has a significantly lower energy density, so jetting has to be fattened appropriately. The sea level jetting from 40 years ago is the 5000' jetting today.
So it is your opinion that peak EGT does not occur just lean of 15, dropping off in either direction until too far off stoich to run?
Please cite references or printouts from dyno runs.
As for jetting, bear in mind that the jets recommended by the factory in 1970-whatever were calibrated with leaded gasoline as fuel. Modern RFG has a significantly lower energy density, so jetting has to be fattened appropriately. The sea level jetting from 40 years ago is the 5000' jetting today.
That's spot-on Jim , modern fuels have changed jetting a lot . I had to have Redline/WorldPac increase stock jetting levels on all the Weber kits to keep up with changes in our fuel . It really shows up on the 38DGAS carbs in their idle jets , the transition for nearly all kits was going far too lean .
Excessively rich mixtures can increase egt's to a point , but more importantly it also washes down the cylinder walls and leads to valve deposits .
Sarge
Excessively rich mixtures can increase egt's to a point , but more importantly it also washes down the cylinder walls and leads to valve deposits .
Sarge
PabloCruise
SILVER Star
Okay, re-reading this post I see you say potentially higher temps...
That was my understanding as well, the reason why leaky brake boosters melt pistons...
Jim always brings a whole extra level of understanding to the conversation.
Washing down the cylinder walls is no bueno...
Agreed, that's a much more important factor than the temp rise.
Stoic is 14.7:1. If you set to stoic at idle, when you're into the mains you're at a much higher AF than you were when set at idle and precisely where more power is needed. I come from the VW/Porsche universe. Air cooled engines are WAY more sensitive to tune than these tractor engines, and from personal experience jetting carbs to run at 7500' from 500' (in an engine far more sensitive to such things) the engine runs hotter. The AF meter I used belonged to a club member, so I'm having to extrapolate based on what I ended up with versus what was running hot (all other things being equal). This observation is corroborated by other carb tuning people in the same sphere. I can't site the specific principle at play, and I don't have any charts. Just recent experience with this exact issue and a CHT gauge.
As for the energy density delta between the old leaded fuels and modern ethanol stuff, the decrease in oxygen available for combustion at altitude is approximately 3% per 1000' above sea level. As detrimental as the changes in fuel composition have been, I don't think the energy density has decreased the full 15% required to make sea level jets equivalent to altitude jets. Additionally, that would make those running leaner jets for altitude painfully lean and cause the well known problems (heat, detonation) that occur when running excessively lean.
I'm not looking for an argument on the subject, just trying to be helpful and weighing in from the perspective of someone with experience tuning carbs between altitudes and the associated effects. I come from a far more sensitive machine, and my results were no doubt more pronounced, but that doesn't mean they're not occurring in the less sensitive Land Cruisers. Run the sea level jets if you want, it'll work and it's your machine. You can't deny that a properly jetted carb won't run better and healthier, that's all I'm saying and all I've said.
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