Going Aisin-details, details, details

[FJ40Jim]

Return that gasket.

Go to local Advance store and order one into the store. Pick up next morning, undamaged.

 

[77mustard40]

Return that gasket.

Go to local Advance store and order one into the store. Pick up next morning, undamaged.

Thanks Jim, stopped by NAPA at lunch and made my case. They have a replacement on the way, due here on Saturday.

 

[77mustard40]

What I know (and don't)

Started tearing down again and this is what I know and don't know:

1. Fuel level in dead middle of sight glass
2. Small intake leak ID's with carb spray on the bottom of 5-6
3. ICS is working, pull the plug and it dies instantly
4. Truck has been driven (and wheeled) in the last month with the leak, above 800-900 rpm its fine. When warming up and first closing the choke knob as its getting warm it wants to run and idle pretty good. I have had to cheat the idle up so i think I may be pulling from the transition slot but it will idle pretty good and transition into throttle ok. Still a little rough though which I have been thinking was vacuum issue since it reads an inconsistent 15-17
5. The longer I run the truck the worse the idle gets, restarting when warm must be choked to idle. It will start without but dies. If I'm stop and go for a period of time I have to ask for some choke or it dies.

When I started taking it apart this evening these issues seemed strange. Truck had sit in a 70 F garage for 2 hours after its last go and I found the inside of the primary to be wet with fuel although the bowl still showed center of the sight glass. When disconnecting the fuel return a lot a gas came out of the return line at the carb, when I opened the gas cap I still had quite a bit of pressure. Im wondering if I have something screwed up with my fuel lines and am jamming fuel down the carb? Ive looked at Jim C's emission schematic and Im struggling since the desmog was the PO and I have a 76 carb on a 77 truck.

I just am not convinced that 100 % of my issues are vacuum related and would love some ideas to chase.

 

[77mustard40]

Any takers?

 

[Pin_Head]

Fix the vacuum leak first and then see what happens.

 

[77mustard40]

Trying to check every possible source of a vacuum leak while the manifolds are off.



Pulled this old crimped piece of what remains from the PO's desmog, looks like the air rail? Found it coming out of the head above No 6 right here




I can look right through the crimped piece but this would be an exhaust leak right? Whats the best way to plug this?

 

[FJ40Jim]

Whats the best way to plug this?

Something like this has worked well.

 

[tucker74]

Something like this has worked well.

X2 - you can get them from Toyota as well, but Jim's kit is complete and cheaper .

Tucker

 

[Rzeppa]

Not meaning to hijack, but I took my carb apart again yesterday and checked the float adjustment. It was exactly 7mm if you include the gasket. Since the instructions said 7mm to the casting, I bumped it one mm, but when I put everything back together it didn't make a lick of difference. The fuel level is still well below the bottom of the sight glass. Not to mention I seem to have lost a rubber washer.

 

[Rzeppa]

Here's the rubber washer I lost one of, and where (I think) it goes. Notice the missing one over there on the other barrel. What does this do? What are those passages for?

Again, thanks for allowing me the (slight) hijack.

 

[77mustard40]

Not meaning to hijack, but I took my carb apart again yesterday and checked the float adjustment. It was exactly 7mm if you include the gasket. Since the instructions said 7mm to the casting, I bumped it one mm, but when I put everything back together it didn't make a lick of difference. The fuel level is still well below the bottom of the sight glass. Not to mention I seem to have lost a rubber washer.

I'm no expert but I would think that increasing the distance in setting the float would actually result in closing the needle seat valve sooner, thus resulting in a lower level in the fuel bowl.

 

[77mustard40]

Here's the rubber washer I lost one of, and where (I think) it goes. Notice the missing one over there on the other barrel. What does this do? What are those passages for?

Again, thanks for allowing me the (slight) hijack.

I can't help you with the rubber washer...I don't recall having them in my 76 carb

 

[Rzeppa]

I'm no expert but I would think that increasing the distance in setting the float would actually result in closing the needle seat valve sooner, thus resulting in a lower level in the fuel bowl.

I decreased the distance from the top of the float to the underside of the top of the carb by 1mm, which should raise the height of the fuel in the bowl correspondingly. It really didn't make any difference. There is some other reason that the fuel won't go to the middle of the sight glass, and it isn't a fuel pump or filter issue, the rig goes like a banshee at any throttle position above idle.

 

[Pin_Head]

The float adjustment does determine the fuel level in the bowl. Since spec is set at the far end of the float away from the hinge, then raising the float by 1 mm is only going to raise the level of fuel by approx. .5 mm, which is a little hard to detect by eye ball.

If it runs great, why worry about the fuel level?

 

[FJ40Jim]

The missing o-ring seals the HAC passages into the top of the emulsion tube. It is probably down inside the throat of the carb. Actually been processed by the engine and shat into the cat converter now, no biggie.
At your altitude HAC should be in full leak mode anyway, so mising the HAC o-rings won't have any effect.

 

[Rzeppa]

The float adjustment does determine the fuel level in the bowl. Since spec is set at the far end of the float away from the hinge, then raising the float by 1 mm is only going to raise the level of fuel by approx. .5 mm, which is a little hard to detect by eye ball.

If it runs great, why worry about the fuel level?

I used digital calipers to measure the float adjustment.

It runs great at all throttle settings except idle. It idles fine when stopped, on level ground or pointed uphill. It stalls when pointed downhill or braking to a stop with the clutch depressed, so my wife won't drive it. There's something wrong and it is driving me crazy trying to figure out the root cause and correct the problem.

 

[Rzeppa]

The missing o-ring seals the HAC passages into the top of the emulsion tube. It is probably down inside the throat of the carb. Actually been processed by the engine and shat into the cat converter now, no biggie.
At your altitude HAC should be in full leak mode anyway, so mising the HAC o-rings won't have any effect.

Awesome, thanks Jim! That is great to know what that missing washer is for. I figured the missing one probably ended up somewhere in the intake manifold and as you write, all the way through the engine.

Indeed, I never drive below 4k feet elevation so the HAC should be in full leaned mode all the time as you wrote.

 

[77mustard40]

Finally back at it





Found a brand new 6-1 header machined with the intake to match flange depth, PO decided to swap to diesel.




Also picked up an insulator and gas filter for vacuum source. Going to put a new secondary diaphragm on the carb since its off and I didnt do that before (preventive measure)

Hope I can finally fix my vac leak and move on to something else.

 

[77mustard40]

Mounted up and torqued part way.



Won't be able to finish today but it's coming.

 

[jmdaniel]

Good luck, Kelly, I know this has been a tough one for ya...