Carb Idle Issue

[ozzstar]

Correct me if I'm wrong David R.

Carb #3 is static, the only way to adjust #3 is with the idle screw. This is why idle should be roughly correct before you start.
Sync #4 to #3. The right bank is now correct.
Sync #1 to #2. The left bank is now correct.
The screw between #2 and #3 balances the left bank to the right bank.

Everything goes off of #3.

So i should adjust the idle air screw on #3 until it is equal to number 4? I thought turning the screw on the right bank adjusted 3 to 4?  Confused 

[SlowOldGuy]

So i should adjust the idle air screw on #3 until it is equal to number 4? I thought turning the screw on the right bank adjusted 3 to 4?  Confused 

WHAO!  You aren't using the IDLE MIXTURE SCREWS to adjust sync are you?  If so, then you need to consult a parts list or manual to find the SYNC SCREWS.

Adjusting the idle mixture screw will not affect sync.  Sync is purely a measure/adjustment of air passing the throttle plate.  If the follow the correct procedure, you will end up bringing all the carbs to read the same as the #3 carb.  Then, when you turn the IDLE SPEED adjuster, the vacuum reading on ALL the carbs will change together.  Hopefully it all changes the same amount, but there could be a slight tweak required when adjusting idle speed.

Confusing? Clarifying?

DavidR.

[ozzstar]

So i should adjust the idle air screw on #3 until it is equal to number 4? I thought turning the screw on the right bank adjusted 3 to 4?  Confused 

WHAO!  You aren't using the IDLE MIXTURE SCREWS to adjust sync are you?  If so, then you need to consult a parts list or manual to find the SYNC SCREWS.

i was responding to the earlier statement by forum member Ratchet: "Carb #3 is static, the only way to adjust #3 is with the idle screw."  There is no confusion to me what screws open and close the butterfly valves for the sync. 

There are more than 2 ways to skin a cat and sync carbs? right?  I use a carb sync tool which has 4 vacumn hoses.  David please clearify this for me.... if i connect all 4 tubes at once to the carbs, have the engine warmed up and idling at 1200 RPM, and have all 4 levels of mercury even at the same level... is my sync correct?   This is how simple i think it is...am i correct?  Otherwise i must be missing something.

Thanks everyone for your help so far, i want to get this puppy running correctly!

[simi_ed]

The idle screw refers to the LARGE knob below the center of #2-#3 carb, only accessable from the float bowl side of the carbies.  I typically adjust mine with a flat blade screw drives, used as a pushing tool on either side of the knob to change idle speed higher or lower.
Hope that clears things a little.
My 2¢

[SlowOldGuy]

i was responding to the earlier statement by forum member Ratchet: "Carb #3 is static, the only way to adjust #3 is with the idle screw."  There is no confusion to me what screws open and close the butterfly valves for the sync.  

There are more than 2 ways to skin a cat and sync carbs? right?  I use a carb sync tool which has 4 vacumn hoses.  David please clearify this for me.... if i connect all 4 tubes at once to the carbs, have the engine warmed up and idling at 1200 RPM, and have all 4 levels of mercury even at the same level... is my sync correct?   This is how simple i think it is...am i correct?  Otherwise i must be missing something.

If you have accomplished the same reading on all 4 carbs, then they are synced.  Sorry for my confusion, you are correct, there are several ways to explain the process and achieve a proper sync.  It sounds like you're on the right track.

I still can't believe your sync is off enough to cause the high idle.  I'm not sure the sync can be far enough off to even cause this symptom.  Then again, I wouldn't really know since I've never had a sync that far out.  Still seems like an air problem to me.  One way to test the choke plunger sealing is to blow into the choke air intake on the carb and see if it raises the vacuum slide.  I know, you said you thought this was good, but it may still be worth eliminating.

If you have the 2-piece throttle cable, have you ever lubed the upper cables?

DavidR.

[Ratchet_72]

Keep in mind that the idle screw positioned in FRONT of the carbs adjusts ALL of the butterfly openings on the 4 carbs and is the only way to adjust #3. None of the other screws will adjust #3. This is because one of the carbs must be a reference point for the OTHER 3 carbs,
I know this is semantics but must be stressed. You'll just confuse the issue if you say "adjust 3 to 4"
Everything adjusts off of #3.
4 to 3
1 to 2 OR 2 to 1 doesnt matter
L bank to R bank OR R bank to L bank doesnt matter

If I had my extra bank of carbs handy I'd take photos but I don't.

Still confused? Is your Choke releasing fully? That may be the cause of a high idle. Maybe the choke cable is adjusted too tight and isnt allowing the plungers to fully release.

[ozzstar]

Still confused? Is your Choke releasing fully? That may be the cause of a high idle. Maybe the choke cable is adjusted too tight and isnt allowing the plungers to fully release.

Yes, i believe the choke is releasing all the way, i have watched the cable and the amount of tension/slack in the cable.  If i pull out the choke knob when the engine begins to slowly loose idle and stall, the RPMS will jump right up w/o a problem.

[ozzstar]

If you have the 2-piece throttle cable, have you ever lubed the upper cables?

DavidR.

No I have not lubed the upper cables since i got the bike.   The throttle cables could stand to be lubed but are not binding or sticking. The throttle grip snaps back sharp.   As i mentioned earlier when the RPM's come up after going down the street for a quick ride, and then it hovers around 2000 RPM, at a stop sign, i can put the bike in first gear, let out the clutch (without any additional throttle) and the RPM's drop down, and tend to stay down, but eventually the idle will drop low enough to cut off.

I still need to get some clear tubing and do the float level check.  Currently there is no more fuel coming out of the choke circuit hoses. 

Having the tank off to check things over i noticed that the tank petcock i have now is leaking.  It has a slow drip out of the main fuel supply nipple.  What can i do to correct this?  Rebuild kit?  Seems when the tank is hooked up on the bike i don't have any gas leaking out overnight, so i assume the floats are working properly.  Is this something to be concerned about?

Thanks

[SlowOldGuy]

Having the tank off to check things over i noticed that the tank petcock i have now is leaking.  It has a slow drip out of the main fuel supply nipple.  What can i do to correct this?  Rebuild kit?  Seems when the tank is hooked up on the bike i don't have any gas leaking out overnight, so i assume the floats are working properly.  Is this something to be concerned about?

I'm waiting for Dan to answer this question in firey, gory detail, but I'll just preview the answer with a YES!  Definitely glue the outlet pipe back into the body of the petcock.  I have a tiewrap around mine to prevent it from falling out.

DavidR.

[Dan Filetti]

I guess it's time I get back up on my personal soap box.. and what a nice lead in...  

To David's point, that little $.50 piece of poorly designed petcock fitting cost me my '85.  She burned to the ground, with nothing left that you could even recognize as an FJ (well, some folks on THIS list may be able to discern that it was what was left of an FJ, but not many...)  In the end, the tow truck driver dragged the charred hulk up onto a flatbed, like the piece of lifeless, never to go again, metal that it was.  Just 30 minutes earlier it had been my shiny FJ, with whom my wife was certain, I was having an affair somehow.

Like you, I noticed that it was loose.  I tapped it back in with a small hammer.  I was foolish to assume that was enough.  It worked itself loose while I was riding and when she went up, with me on it, the fire ball was I'm told, 8 feet in diameter.  In all seriousness, and I just can't stress this enough:  

Seal and Twist-Tie those Fittings

It's one of the few serious design flaws of the FJ, and there are potentially dire consequences for not addressing.  

Climbing back down off my soap box now...

Dan

[threejagsteve]

To David's point, that little $.50 piece of poorly designed petcock fitting cost me my '85.  She burned to the ground, with nothing left that you could even recognize as an FJ (well, some folks on THIS list may be able to discern that it was what was left of an FJ, but not many...)  In the end, the tow truck driver dragged the charred hulk up onto a flatbed, like the piece of lifeless, never to go again, metal that it was.  Just 30 minutes earlier it had been my shiny FJ, with whom my wife was certain, I was having an affair somehow.

Like you, I noticed that it was loose.  I tapped it back in with a small hammer.  I was foolish to assume that was enough.  It worked itself loose while I was riding and when she went up, with me on it, the fire ball was I'm told, 8 feet in diameter.   

Well, if that tale didn't shiver me timbers! Actually went looking on a parts fiche to see what an '85 petcock looks like -- just like the petcock on almost every bike I've ever ridden.

There's nothing like a story like that to remind us all that every time we let out the clutch we're balancing a 5-gal. Molotov cocktail between our knees, right over the ignition source...

Sorry about your loss, Dan. Thanks for sharing your experience!

[ozzstar]

I'm waiting for Dan to answer this question in firey, gory detail, but I'll just preview the answer with a YES!  Definitely glue the outlet pipe back into the body of the petcock.  I have a tiewrap around mine to prevent it from falling out.

DavidR.
[/quote]

I will have to check the outlet pipe a little more but i thought it was dripping out of the pipe.  It didn't seem to be an external leak.   When i connect the fuel line there isn't any drip.  I am speaking of an 'internal' leak in the petcock itself.   Is this possible and what are the options to repair it?  Thanks

[RichBaker]

Sounds like the internals aren't sealing. You should be able to take the petcock apart and replace the o-ring and whatever else is in there...

[SlowOldGuy]

Sorry, my bad.  Your shut off o-ring had probably deteriorated.  Replace it with a 5mm ID X 2mm Cross Section o-ring.  You might want to also beef up the spring behind the diaphragm.  Take the one that's currently in the petcock to the hardware store and find a slightly stiffer replacement.  Don't go too much stronger, or the vacuum might not open it.

And while you've got the tank off, check the tightness of the outlet just for the heck of it.  Tugging on the fuel hose tends to loosen it.  Put a tiewrap around it anyway.

DavidR.

[ozzstar]

Sorry, my bad.  Your shut off o-ring had probably deteriorated.  Replace it with a 5mm ID X 2mm Cross Section o-ring. 

DavidR.

Any ideas where to find a metric O-ring thats is of good quality.  I don't trust Harbor Freight with there quality, I know they sell metric oring kits. 

How do i get to the shut off o-ring/spring?  The petcock looked liked it was riveted.  Do i need to drill and replace with bolts?  If you could please give me a little more info on the repair process I would appreciate it.  Thanks

Ozz