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Hi y’all,
Can’t get my 85 22r idle down. Original Aisin carb.
It has no fast idle at start, starts around 750-800 and as it warms up (choke plate full open), it rises up to 1150-1250rpm and stays there. I’ve rebuilt the carburetor and replaced the vacuum hoses and I’ve backed the idle adjust screw out to the point where the cam doesn’t make contact with it at idle. I’ve sprayed carb cleaner and propane around looking for a leak somewhere and got nothing.
Do you have initial timing set properly? Are you adjusting the right screw for idle speed? Don't be offended. Link below to download FSM if you need it.
Do you have initial timing set properly? Are you adjusting the right screw for idle speed? Don't be offended. Link below to download FSM if you need it.
Yes, thanks, I should have mentioned that the timing is good, and yes, that’s the idle screw I’m looking at that isn’t touching anything (there’s a gap at the end of the screw, which makes me think something is keeping it rev’d up…
When I unplug the vacuum from the choke breaker opener diaphragm, the fast idle cam stays up and the engine idles high as it should, and a blip of the throttle kicks the cam down as it should. So I’m guessing there’s too much or too early of vacuum for some reason? Or the diaphragm spring is weak?
Last edited by burntcloth; Sep 7, 2025 at 09:50 AM.
Test the choke breaker, p. EC-62. It's job is to "...slightly open the choke valve to prevent a too rich mixture after firing when the choke is closed." Did you open the choke breaker and replace the diaphram with the rod that extends in to the choke? e clip back?
The choke opener is the one that holds the choke valve open and releases the fast idle cam. Test in FSM on EC-63. The choke opener isn't opened during a rebuild. So I don't know what's inside it.
52502512]Test the choke breaker, p. EC-62. It's job is to "...slightly open the choke valve to prevent a too rich mixture after firing when the choke is closed." Did you open the choke breaker and replace the diaphram with the rod that extends in to the choke? e clip back?
The choke opener is the one that holds the choke valve open and releases the fast idle cam. Test in FSM on EC-63. The choke opener isn't opened during a rebuild. So I don't know what's inside it.
Oops, sorry, I got that wrong. It’s the choke opener that I disconnected to get the fast idle cam to stay at startup. Good intuition on your second guess…maybe it’s BVSV related.
...
Okay, got the BVSV (or the BVSV #1 ?), the three-ported reddish-brown thermo valve on the intake manifold. Aisin 25810-27010 written on the side. I did the test per the FSM EC-60 and I couldn't get any air to blow through the top port until I put compressed air into it and that blew it loose. Problem is that when I blow on the valve hot, air comes out the top, but if I plug the top port, it (weakly) comes out the bottom port. Same problem (but opposite) for when it is cold. Which makes me think the valve is shot. That part isn't available anywhere new, apparently.
Last edited by burntcloth; Sep 7, 2025 at 04:54 PM.
Okay! Got the idle down. Turns out it was just the throttle cable being too tight. Ugh. Worst part was that I had checked for that already, even disconnecting the cable while the engine was idling. I can only assume the throttle arm hung up somehow on that test. Passed smog!
Aug 29, 2025 | 08:47 AM
