FJ60 Intermittent Stall at Idle

[Rzeppa]

Here's a new data point:

On the spooky night run, I had no issues whatsoever going uphill, however she absolutely would not idle at all when pointed downhill. I peeked inside my spare carb and can't really tell what might be different when pointed uphill versus downhill...anyone have any ideas?

 

[MDH33]

Here's a new data point:

On the spooky night run, I had no issues whatsoever going uphill, however she absolutely would not idle at all when pointed downhill. I peeked inside my spare carb and can't really tell what might be different when pointed uphill versus downhill...anyone have any ideas?

Probably not an uphill vs downhill thing, but more likely you're off the gas pedal going downhill. Really sounds like a carb adjustment thing to me. Maybe the butterfly is closed all the way when you're off the gas rather than being slightly open like it should be. Have you taken the carb off to inspect all that and the linkage, etc?

 

[Rzeppa]

Probably not an uphill vs downhill thing, but more likely you're off the gas pedal going downhill. Really sounds like a carb adjustment thing to me. Maybe the butterfly is closed all the way when you're off the gas rather than being slightly open like it should be. Have you taken the carb off to inspect all that and the linkage, etc?

I could take my foot off the throttle pedal while going uphill and still keep going. Whenever I was pointed downhill it would stall every time I put the clutch in.

Does anyone know exactly where the fuel for the idle circuit is drawn from? I am wondering if it is from the top of the fuel (as opposed to the bottom where the primary and secondary jets are). If it is in the top rear of the bowl, maybe my float is a little too low?

 

[MDH33]

If the float was too low/high, you could see evidence in the sight glass I would think. Is it always in the middle?

 

[Rzeppa]

If the float was too low/high, you could see evidence in the sight glass I would think. Is it always in the middle?

I never really thought to check until just now kind of thinking about the uphill/downhill business. Since she runs GREAT at all throttle settings above idle it just wasn't something I thought to check. Normally I look at the sight glass on a rig that seems to be having fuel delivery issues (vapor lock, fuel pump, etc.)

But when you take the top off a carb and take the idle solenoid off, there is one passage that goes down to the mixture screw, and then from there to the throttle body just below the throttle plate. So I was wondering where the fuel comes from that goes to the idle solenoid (upstream)? It must come from the top rear of the float bowl, right?

 

[trucruiser]

Jeff,
Im still convinced its your carb, Get a rebuild or another and I think your head scratching will be over. I went through this same thing until I popped a new to me carb on and it hasnt died since.

 

[Rzeppa]

Jeff,
Im still convinced its your carb, Get a rebuild or another and I think your head scratching will be over. I went through this same thing until I popped a new to me carb on and it hasnt died since.

Well, I certainly agree that it is most likely the carb! The fact is, this carb was rebuilt only a few thousand miles ago, and everything was fine until I changed out the primary jet to pass emissions. I put the old jet back in, but it just has this weird thing where it wants to die when you are either braking or pointed downhill. I wonder if I buggered the float level when I changed the jet? I need to take a peek at the sight glass.

 

[Rzeppa]

This evening I got around to peeking into the sight glass and didn't see any fuel! Since modern gasoline is transparent, it is pretty hard to use the sight glass these days, but I am pretty sure the level is below the sight glass.

So methinks I somehow buggered the float when I changed out the jet and need to get back in there and raise the level.

I was looking at the float on my spare carb and it *looks like* I should bend the little doo dad (tech term) downward to raise the float level, right?

 

[RicardoJM]

...
I was looking at the float on my spare carb and it *looks like* I should bend the little doo dad (tech term) downward to raise the float level, right?...

Yuppers.

 

[MDH33]

I was looking at the float on my spare carb and it *looks like* I should bend the little doo dad (tech term) downward to raise the float level, right?

I think you're supposed to bend the Two doo-dads to either side of the center one to adjust float height. I don't have one in front of me to reference though. There's even a SST for gauging the height. I just made one out of a junk-mail credit card. Works great.

 

[Rzeppa]

OK, there's only one doo dad. It is a tab in the sheet metal of the frame that holds the float, and when the float goes upward it presses against the needle valve to close it. Tomorrow I will go take a picture of what I'm talking about.

 

[rover67]

that's the doodad you bend to adjust what level the valve closes at. bent it down towards the float to raise the level of fuel. usually there is a spec for float height when you turn the carb upside down and the float rests with its weight against the needle valve. also make sure your float dosent have fuel in it, sometimes they leak then they don't float right.

 

[Uncle Ben]

http://media.photobucket.com/image/adjusting%20float%20level%20in%20aisin%20carb/pacapo/Aisin%2520Carb/Aisin2.jpg

 

[RicardoJM]

Martin and Marco are correct, there are side adjusting tabs and a center. All three are used to set the full range of motion for the float. Here is a picture, the side tabs controls how "low" the float drops and the center tab controls how "hight" the float rises.

 

[Rzeppa]

also make sure your float dosent have fuel in it, sometimes they leak then they don't float right.

Oh you know what? I need to check that too! That happened to my lawnmower this past summer and it kept flooding. Except I just thought of something - I don't have a flooding problem, it looks like the fuel level is too low.

 

[Rzeppa]

http://media.photobucket.com/image/adjusting%20float%20level%20in%20aisin%20carb/pacapo/Aisin%2520Carb/Aisin2.jpg

Thanks for that link Kevin! My Haynes doesn't show that spec.

I still wonder how I buggered it up just from changing out the jet through the port in the front.

I have noticed that the rod that the float pivots on doesn't have anything to keep it from sliding one way or the other. Maybe the carb casting is what holds it in place?

 

[subzali]

Nothing to add really, except a link to a guy on MUD who is having trouble with his FJ40 stalling on downhills:
http://forum.ih8mud.com/40-55-serie...in-details-details-details-3.html#post7108885

 

[Rzeppa]

Thanks Matt! I just posted up there. It sure looks like that guy has a similar symptom.

 

[Hulk]

I don't have anything to add, but I am posting this diagram to the RS website just in case photobucket goes kaput someday in the future.

 

[subzali]

So that guy on MUD had an extra o-ring on his needle valve. So not sure if that's the same problem you have Jeff. Probably not.