Rebuilt 2F seems to be going down hill (1 Viewer)

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Thinking back... I think that when I mounted my Mark-rebuilt and tuned carb, I had the same sort of high idle issue. I had forgotten this, but I definitely had a problem getting the idle down.

Until I thought of the fast idle screw... turned out that Mark set the fast idle screw up (fast)... for some reason.

He had a legit explanation, when I asked him about it, but I can’t recall, now, what it was.

Try adjusting the fast idle screw to allow the basic idle to idle slower.

Check the picture Mark (@65swb45) labled, in post #6 here —> Tuning the carburetor in a 77 fj40

Edit: Actually post #7 has a labeled picture.
 
Last edited:
When you say it wont idle below 1000, do you mean it stalls and dies or that the idle screw wont let it go any lower?

Check out this diagram and note #7 and #15 . If they are clogged then your idle circuit isnt workiing so yo have to open the idle screw enough to get fuel through the main jet. If you unplug the idle solenoid the engine should die. If it doesnt start searching for why. At idle the only fuel should be from the idle circuit. I bet it is clogged around #15 or linkage is binding. HTH

Carb Cirucits 2f Aisin FJ60_labeled.JPG.jpg
 
I’ve seen that diagram before, but it never made any sense to me. After watching Pinheads carb videos today and pulling the air horn off my carb tonight I can finally understand it a little. I have a theory that 1) if works will make me feel ecstatic and stupid at the same time or 2) I don’t know what....have a good cry in my beer (or something much stronger).

So I have another carb (trollhole maybe...it came with my 40). I tried to install it as a test but it wouldn’t sit flat on the insulator. I removed my solenoid tonight and used jumpers to power it. It clicks (which I knew already) but it was very hard to see a tiny amount of movement. I don’t see how much fuel could get past that needle. I pulled the solenoid off the other carb and tested it. The click sounded stronger and I could see more movement of the needle. So I’m putting the carb back on with the solenoid and I’ll see what happens.

I’m leaving this weekend for a trip, so this is my last attempt for a few weeks. It would be assume to have this resolved before I leave.

I’ve become a pro at installing and removing the carb. I just need to find a very short 12mm wrench because the nut next to the throttle linkage is a major PITA.
 
So you pulled the idle mix adjustment screw as a means of dislodging any debris which may have bottle-necked there? Also make sure that the tip is smooth and looking like a manufactured taper.
 
Dizzy said:
So you pulled the idle mix adjustment screw as a means of dislodging any debris which may have bottle-necked there? Also make sure that the tip is smooth and looking like a manufactured taper.
Click to expand...
Yep and confirmed the smooth taper.


emac said:
What happens when you turn down the idle screw? Does it stall or just stay high idle?

With engine running unplug the solenoid. What happens?
Click to expand...
I’ve tried adjusting the idle mix screw .....fully closed, fully open, 2-1/2 turns open. It doesn’t make any difference. If I release choke or let up on pedal it dies.

Let me say again thanks for everyone’s replies. I know this issue has come up many times on mud (because I’ve read them researching the issue). I tried to explain all I’d done so far, but I could have been more detailed. I didn’t want to write too long a thread/question, but I’m happy answering questions.

I can’t explain why it’s started running a litttle rough, but the idle problem is the old classic idle circuit failure or vacuum leak right..... but I’ve not been able to nail down either issue. That said I’m now hopeful it’s my solenoid that was clicking but (after visual inspection and comparing to another solenoid) i think perhaps the needle was not functioning properly.
 
If the idle mixture screw has no affect on the idle then I would guess the engine is NOT idling with the idle circuit so you have to figure out why. Either the idle circuit is clogged or linkage/something is holding the main open.

I would remove the idle solenoid and the idle mixture screw and blow (not high pressure) air through the circuit and see if that clears it out. If that doesnt work look for any obstruction (gasket,bent linkage,etc) that could be keeping the butterfly open. I have been here before and feel your pain. I have a brand new carb sitting in my closet that I ordered and before it came I found the piece of trash in the idle circuit.
 
Your cut off solenoid looks the same as on my Trollhole carb. I found that when energized, the inner plunger rod pulls back and opens the path from the side holes to the end hole. When energized , I could pass a small wire through each pair of the side holes to make sure they weren’t blocked. I also put the tip of solenoid to my lips and blew through it while connecting and disconnecting the 12v source to confirm it was indeed opening and closing. I guess carb cleaner will work also but my lips were close by and beer removes the gasoline taste. Sort of.

During my last trip on the trail my F.5 started doing the same thing as your 2F so I’m following this thread closely. Mine is also acting like the idle circuit is not functioning. 1100 rpm and up, it runs fine. Below that, it stalls. I removed the carb and pulled the top off like you to clean. I blew carb cleaner and air through all the passages. I believe I traced out the idle circuit and blew cleaner, in steps, from the exit hole in the throat back up and through to the bowl. I removed all parts I could get to one by one to clean & blow through and then replaced. Re-assembled, installed and it still won’t run below 1100 rpm.

I’m gonna remove the carb again and will open it again. I have a rebuild kit now so I may go further. I was hoping to find some trash like emac the first time but didn’t. Maybe on the second try.

I also have another Trollhole on my 60 that’s running fine so I might do a swap and that should tell me something. Hope you get yours sorted and the fix will help me with mine. Good luck!
 
IMG, how stupid am I ? Just popped my hoods to do the carb swap and went to get my wrenches. Left them where I disassembled the carb. What a dummy. I left out the solenoid. Jeeeeezzzzz!
Ok, I'm putting this in and will report back in a few.

CutOff 01.jpg
 
Progress! I put the carb back on this morning with the new(er) idle solenoid. After warming up I was able to open the choke and had it idling at 600rpm!!!! This was with the idle speed screw not engaged at all and the idle mix screw turned out 4 or 5 turns. I realize that is too low and as a result it wasn't really purring. At that point I had to shut it down and get to work. But....IT'S IDLING so I can now start to adjust the carb and timing. For the first time it was obviously running off the idle circuit with no fuel coming from the primary. I did try to adjust the idle speed screw right before turning it off with no effect. I realized at the screw wasn't hitting the little pad to push the throttle. Something on the linkages wasn't lined up correct. I'll have to investigate. (this hasn't been my problem all along because I have been able to increase the idle with that screw this week). Not sure why it wasn't aligned this morning.
Anyhow......
I checked my idle solenoid a dozen times (or more) in the past week and even 'hot wired' it straight to my battery. clickety click click. Hearing a click isn't good enough (at least not for mine).
Unfortunately I have to put mine to bed for a few weeks (although I may get to sneak into the garage for an hour tonight) but it feels good to have made some progress.

 
That's great! Mine idles now with the solenoid installed. So stupid of me leaving it out. But at least now I know that the flushing out the idle circuit fixed my problem.
Maybe your solenoid was bad or maybe you dislodged an obstruction by removal and replacement. Either way, good news.
 
When I get a chance I'll see if my old solenoid can be cleaned (if there was some gunk behind the needle perhaps). I'm curious and if I can get it clean I'll have a spare.

What's amazing to me after opening the carb is the size of the idle circuit......that you can idle that big straight six off that tiny little hole in the tip of the idle solenoid.
 
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