Going Aisin-details, details, details

[Pin_Head]

Sorry for being pedantic. I had to check, since you didn't explicitly mention the ground wire and not everyone is familiar with how the wiring works. I know some wrench turners that won't go near a wiring diagram.

Low fuel level might explain it too. The idle fuel hole in the bowl would tend to be above the fuel level when it going down hill if the fuel level was low. The thing that doesn't fit with this is that the problem should be worse at higher speed as it uses more fuel above idle. It is not too hard to take the top cover off, check the float and needle valve for smooth operation in both orientations and blow out the idle fuel circuit with compressed air. If that doesn't do it, I would just take it off, dip it and put a kit in it and hope for the best.

I would be inclined to put a band aid on it and just bump up the idle speed if that worked.

 

[Rzeppa]

Sorry for being pedantic. I had to check, since you didn't explicitly mention the ground wire and not everyone is familiar with how the wiring works. I know some wrench turners that won't go near a wiring diagram.

Low fuel level might explain it too. The idle fuel hole in the bowl would tend to be above the fuel level when it going down hill if the fuel level was low. The thing that doesn't fit with this is that the problem should be worse at higher speed as it uses more fuel above idle. It is not too hard to take the top cover off, check the float and needle valve for smooth operation in both orientations and blow out the idle fuel circuit with compressed air. If that doesn't do it, I would just take it off, dip it and put a kit in it and hope for the best.

I would be inclined to put a band aid on it and just bump up the idle speed if that worked.

No worries Charlie, I remember your great advice from our CCOT forum days. Yeah, the thing that has me scratching my head is that the rig goes like a banshee at every throttle setting above idle, and at idle when pointed uphill. The rig has a MAF motor, which probably means an RV cam - she's got a really low, throaty sound, different than any other 2F I have ever driven, and I have driven a lot. Stock manifolds, no header. Vacuum is lower than normal too, which suggests the long duration cam.

I was originally planning to use compressed air to blow out the passages in the idle circuit when a tech at a Land Cruiser business I stopped off at suggested using carb cleaner instead. As I wrote, I did and observed free flow though the passage between the solenoid and mixture screw.

The carb was kitted less than 2,000 miles before I got it, and appeared as clean as a whistle when I took the cover off to inspect for crud. The thing about fully smogged 60s is all the cr@p in the way - taking the carb cover off is about a half hour job compared to my other rigs which are more like about 10 minutes. But I figure that's what I have to do, at a minimum to check the float adjustment and operation.

 

[Rzeppa]

Oh and on the band aid - I already have the idle set at about 1,200 RPM when it isn't stalling...

 

[Pin_Head]

You could also rebuild another core. Sometimes it is easier to just throw in the towel.

 

[77mustard40]

You could also rebuild another core. Sometimes it is easier to just throw in the towel.

Hit me up if you need help screwing up a rebuild or looking up some of the vernacular popping up in the this thread. I'm eager to contribute somehow.

Seriously, even if it looks clean and the passages look clear you may need to take the plunge with the rebuild. Although it may seem unlikely I would guess there may be something in the idle circuit somewhere that is causing a problem. Good luck, you are engaged with one of the right guys (not me)

 

[FJ40Jim]

The issue started when I changed out the primary jet to pass emissions. I thought it was because of the jet, but the problem remained when I put the old jet back in. Prior to that she idled fine under all conditions.
I think it is a float problem too, but what I am trying to wrap my brain around is how it could have happened simply by changing out the jet through the port on the front. At one point I took the top off the carb and inspected it and could not find anything obvious, like crud in the bowl, but I did not check the float adjustment at that time. I have never seen or heard of a float that needed adjustment once it is set. I guess it could happen?

Correlation does not equal causation.

The only reason I am wondering about the float is because my fuel level is at the bottom, or slightly below the bottom of the window. That, and maybe I bumped it and buggered it somehow when I was changing the jet?

Regardless of the cause, the float level is too low. To run reliably, the fuel level needs to be on the sight glass. Anywhere in the middle 50% seems to be fine.

 

[77mustard40]

Got a problem and I don't think it's related to my previous issues. After my last post last week I purchased a tach and adjusted the carb, all was great until today. Drove to work this morning and all was good when I noticed after exiting freeway and was engine breaking I could hear some heavy exhaust gurgling and backfiring. Vehicle stalled and will no longer idle without half to two-thirds choke to engage fast idle. Got home this afternoon and pulled the air cleaner, looking down when I open the choke butterfly on top with my hand it will want to stall. Also noticed what appears to me to a lot of fuel pouring out of the primary nozzle (this is with the fast idle engaged). Again I'm a carb novice but this does not seem right, thoughts?

 

[Fast Eddy]

Got a problem and I don't think it's related to my previous issues. After my last post last week I purchased a tach and adjusted the carb, all was great until today. Drove to work this morning and all was good when I noticed after exiting freeway and was engine breaking I could hear some heavy exhaust gurgling and backfiring. Vehicle stalled and will no longer idle without half to two-thirds choke to engage fast idle. Got home this afternoon and pulled the air cleaner, looking down when I open the choke butterfly on top with my hand it will want to stall. Also noticed what appears to me to a lot of fuel pouring out of the primary nozzle (this is with the fast idle engaged). Again I'm a carb novice but this does not seem right, thoughts?

Sounds like you lost power to the idle solenoid maybe...

 

[77mustard40]

Sounds like you lost power to the idle solenoid maybe...

Confirmed solenoid is fine and operates from keyed source, fuel dead center in the sight glass...gas seems to be pouring down the throat and I'm at a loss at the cause.

 

[Pin_Head]

Gasoline is normally pulled out of the main nozzle when the choke is set.
Could be a large scale vacuum leak.

The exhaust gurgling and back firing is probably related to the "desmog".

 

[77mustard40]

Can't find a visible vacuum leak so I'm going to pull PCV and clean it up (or replace it) and replace the PCV vacuum line to the manifold. Noticed oil on the hose at the manifold.

Stupid question of the day, how does the PCV come out of the fitting on the block below #6?

 

[FJ40Jim]

To remove PCV valve, just grab it w/ a chanellock and pull upward. The rubber grommet is pretty hard after years of oil exposure, making removal difficult. Order a new PCV & grommet from the dealer if there's any questions.
BTW, if grabbing the PCV w/ the channollocks results in a crushed PCV, that's an indicator that the chintzy chinese PCV valve needs replaced w/ a billet steel Toyota valve.

If the carb was idling fine, and suddenly stopped, it's usually because of a loss of power to the ICS. If that tests fine, then it's a fleck of dirt stuck in the end of the idle jet.

 

[77mustard40]

Update. I got the PCV out and the grommet was plastic toast, clearly it's first removal since it left the factory. Picked up new parts at the dealer counter yesterday and installed last night along with a new hose.

Did not have time to work on going through the carb setup again but drove it in to work this am. I may have found the PCV to be the problem, seemed to drive well and idle was elevated once warm and choke closed ( I expected this since I turned up the idle speed and mixture last week to compensate). I'm planning to add the vacuum gage and tach when I get home this evening and re-tune the idle and mixture. Cautiously optimistic.

 

[Hugh Heifer]

Great thread.

 

[77mustard40]

the carb was idling fine, and suddenly stopped, it's usually because of a loss of power to the ICS. If that tests fine, then it's a fleck of dirt stuck in the end of the idle jet.

Cautious optimism may be just that, I have decided to go back in and re-dip and re-clean the bowl and all it's circuits. You are probably right Jim, there must be something in the idle circuit messing with me.

 

[77mustard40]

Base has been cleaned, the bowl is on the Berryman's boil. Hope to reassemble tomorrow.

 

[Pin_Head]

You need to be dilligent when it comes to rinsing it and blowing out all the tiny holes with compressed air. I like to run a piece of nylon monofilament through the tiny holes to verify they are open.

 

[77mustard40]

You need to be dilligent when it comes to rinsing it and blowing out all the tiny holes with compressed air. I like to run a piece of nylon monofilament through the tiny holes to verify they are open.

Great suggestion. Only problem is I got home from dinner with the wife and got a wild hair and cleaned and reassembled the carb.





Just finished the whole job when I took this pic and went to my phone and saw your most excellent suggestion. Kind of feel like a cross between Homer S and the dad on Christmas Story trying to set a personal best with the ole tire change.

Anyway, sweet thing is asleep so I will fire it up in the morning and see if I accomplished anything. If nothing else, I'm starting to feel like I can work on one of these things at Happy Hour.

 

[77mustard40]

All you vacuum leak guys have been vindicated, I think I have a manifold leak somewhere near #2. Once I got the right angle shooting carb cleaner between the manifold and head I saw the idle jump up a good 500 rpm's. Weather is headed south this weekend so here goes a dig a little deeper, never pulled my intake and headers. Who's got the best gasket, TEQ?

Carb work was probably good all along, but hey I got a lot of training!

 

[duffontap]

Well, if you ever write an autobiography, you'll have enough carburetor rebuilding material for five chapters!