frustrated with aisin carb

[badass]

I just got done rebuilding my carb, now i installed it and it is still having the same symptoms Still runs super rich, even with the mixture screw turned all the way in, yes it runs with the screw turned ALL the way in. I bought a vaccum gauge and timing light. Hooked up the gauge, i have steady vaccum around 15-18. Now i don't know exactly how to time an engine but i will try tomorrow in the daylight. Just want to know if timing could really make an engine run that rich???

 

[Fast Eddy]

I just got done rebuilding my carb

Maybe you need a new mechanic? coughJimCcough

 

[badass]

Maybe you need a new mechanic? coughJimCcough

Eddy, i contacted jim and was going to send it out for a rebuild, but this was not an option for me due to the fact that this is my only vehicle and jim's turn around time is 3 months +. So please stop telling me i should have sent it to jim, i already know that. Just trying to figure out how to solve my problem.

 

[Rocky_LC]

Timing will not affect the lean / richness of the carb. What it does is change where in the firing stroke the fuel is ignited.

If it's way off, it probably can cause incomplete combustion (which might smell like richness) - but based on your description, it's probably in the carb.

Good Luck -

Rocky

 

[IDave]

If you are getting gas at idle with the idle mixture screw turned in all of the way, then perhaps this is because you have either the idle speed too high (throttle plate open) or the fast idle set too high.

 

[Mark W]

Your engine should run with the idle mixture screw turned all the way in. you've got something wrong in the carb. Possibly float set too high. Possibly secondary butterfly not closing completely. A couple few other things can cause this, but these are the most likely.


Mark...

 

[badass]

Your engine should run with the idle mixture screw turned all the way in. you've got something wrong in the carb. Possibly float set too high. Possibly secondary butterfly not closing completely. A couple few other things can cause this, but these are the most likely.


Mark...

Mark, secondary does close all the way, I was not aware that i could adjust the float, how so? Also the glass is half way full all the time. When i took the carb apart the primary hole had the secondary jet in it and the secondary hole had the primary jet in it. When i saw this i figured problem solved, but i guess not... I've been reading and i'm thinking other than a float problem, my problem is probably vaccum lines, i don't have any leaks and the engine is desmogged. But from what i've read people are saying the power valve must have vaccum or the engine will run very rich. I just don't know where the power valve is located. Also my dizzy does not have any vaccum hooked up to it.

 

[grant5127]

when you have it idle... look down the throat... is fuel drooling down the venturi?

 

[Cruiserdrew]

Maybe you need a new mechanic? coughJimCcough

Based on other recent threads, this is the most erudite comment yet!

Seriously, badass, if you can't time an engine, how in the world do you expect the engine to run well? The carb may be perfect, but you just won't know. It sounds like you have a lot more work to do. Good job tackling the carb rebuild yourself.

Do ALL the basic tune up stuff. Adjust the valves, adjust the timing, check compression etc. Check everything, even if you think it's OK. These engines are not that hard to get running as well as they can.

 

[Pin_Head]

Like Dave said, if you have the idle speed screw set to high it will run with the idle mixture screw closed because it is pulling fuel out of the main nozzles, which you can see like Grant mentioned. The float level sounds fine if the fuel level is half way up the glass. If you have a '79 carb, it does't have an external connection for the power valve control, so this is not an issue for you.

If you did an intial adjustment of the idle speed screw as detailed in the FSM, you should be in the ball park for proper adjustment of the idle mix and speed by the lean drop method, which is also in the FSM. You did buy a FSM, right?

 

[Coolerman]

Post up a pic of your carb and engine bay, especially drivers side engine, you may not have the carb you think you do. Also who did the de-smog? VERY common problem is a de-smog done incorrectly resulting in poor running. Pics are worth a thousand words here.

 

[Cruiser_GT]

Post up a pic of your carb and engine bay, especially drivers side engine, you may not have the carb you think you do. Also who did the de-smog? VERY common problem is a de-smog done incorrectly resulting in poor running. Pics are worth a thousand words here.

x2! Let's see how everything is connected.

As for setting timing... experience has led me to sit my timing light aside for my desmogged '78. I use the vacuum gauge and adjust dizzy to max vac (with carb vac advance port disconnected an capped). Then I back off slightly and reconnect my vac advance.

Next I readjust my carb using the lean drop method documented in the fsm and also on several threads here on mud... then I check my dizzy again... and idle again... round and round until all is well tuned.

Next... adjust the valves and to quote Poser... "call it good."

 

[dirtcurt]

Did the carb ever run good, and when did it go south? Did it just start running rich? Could you have mis-fueled it with a can of diesel?(I've done that). Is the fuel OK? When you say the carb had jets reversed how did you figure that out? Maybe they were correct in the first place.

 

[badass]

Did the carb ever run good, and when did it go south? Did it just start running rich? Could you have mis-fueled it with a can of diesel?(I've done that). Is the fuel OK? When you say the carb had jets reversed how did you figure that out? Maybe they were correct in the first place.

NO, since i purchased it about a year and a half ago the carb has sucked. It runs beautifully and never stalls but it is always running rich. Also, starting it cold was always a problem, so i ended up tightening the line on the choke from the carb so the choke is always 1/4 on. If i don't do this it will be very difficult to start it, even if it is 100 degrees outside. I always put 87 octane gas in it. I figured it had reversed jet cause while i had it apart the jet that had a 2 stamped on it was in the primary hole and vice-versa. Plus the one with the 2 on it which was in the primary slot had a much bigger holes in it. Timing is probably fine, but it hasn't been touch since i bought it so i will check it to make sure it is ok. Just need to learn on how to time an engine first. I will take pics tonight, could vaccum be causing this? BTW, dizzy has no vaccum going to it.

 

[badass]

Post up a pic of your carb and engine bay, especially drivers side engine, you may not have the carb you think you do. Also who did the de-smog? VERY common problem is a de-smog done incorrectly resulting in poor running. Pics are worth a thousand words here.

Coolerman, When i recieved the fj40 pretty much all of the smog crap was there except the most important piece, the vsv. Air pump was frozen still, and nothing was hooked up, it was just there. So i removed it and it made no difference other than clear up space. So basically the po did the desmog.

 

[Cruiserdrew]

If the choke is always 1/4 on, that's why it's rich at idle.

There definitely should be vacuum to the carb, but only when the throttle gets opened up. At idle, the distributor advance should have no vacuum.

Are you sure you don't have a huge vacuum leak in the system? The brake booster is a possible source and can be easily and temporarily eliminated from the system by plugging the vacuum line.

Swapping the jets does not seem like something you would need to do. You may have compounded your problems.

If the engine will run at idle, you can get the timing right. If not, you may need to time it by ear or with a vacuum gauge.

My bet is still that the carb is not right, but you need to go through systematically one item at a time to solve this puzzle. Good luck.

 

[badass]

If the choke is always 1/4 on, that's why it's rich at idle.

There definitely should be vacuum to the carb, but only when the throttle gets opened up. At idle, the distributor advance should have no vacuum.

Are you sure you don't have a huge vacuum leak in the system? The brake booster is a possible source and can be easily and temporarily eliminated from the system by plugging the vacuum line.

Swapping the jets does not seem like something you would need to do. You may have compounded your problems.

If the engine will run at idle, you can get the timing right. If not, you may need to time it by ear or with a vacuum gauge.

My bet is still that the carb is not right, but you need to go through systematically one item at a time to solve this puzzle. Good luck.

Well, currently the choke is not on, and even with it not on, it still runs rich. Correct me if i am wrong but the jets are the two things that have a pole coming out of them with holes on the ends, right? Well currently i have the vaccum gauge hooked up to the brake booster vaccum line. I'll be home in about an hour and will check for leaks. Thanks.

 

[Pin_Head]

What makes you think it is running rich? This isn't so easy to know.

The long skinny jets are what Toyota calls "slow jets" and other people call air correction jets. The main jets are smaller slotted screws with holes in them that face forward into the fuel bowl. The fact that you ask what these are indicates that you either don't have the FSM or have not read it. Rebuilding your carb without having the FSM is a big mistake.

 

['74 UA FJ]

When you say it's running rich, what do you mean? Black smoke? Fouled plugs? Or just a smell? If it's just a smell I would forget about it and drive it. If you aren't smoking or fouling plugs there's no real problem.

 

[Cruiser_GT]

What makes you think it is running rich? This isn't so easy to know.

The long skinny jets are what Toyota calls "slow jets" and other people call air correction jets. The main jets are smaller slotted screws with holes in them that face forward into the fuel bowl. The fact that you ask what these are indicates that you either don't have the FSM or have not read it. Rebuilding your carb without having the FSM is a big mistake.

x2!

When you get to the house, can you snap a couple of pics showing the carb (and it's vac lines) as well as the dizzy?