Anal Retentive Analyst
- Nov 3, 2011
- Carson City, NV
You know what I’ve found in all my Cruiser adventures? If your clueless after trying multiple times, hand it over to a new set of eyes. It’s easy to burn out because this doesn’t come naturally to many of us. Grasping a straws won’t do it. Whether it be Jim or some other mud or not mud person, get it rebuilt not by you and let go of the stress. They’re will be something more to focus on, you know it. We all have gone through this.
You know what I’ve found in all my Cruiser adventures? If your clueless after trying multiple times, hand it over to a new set of eyes. It’s easy to burn out because this doesn’t come naturally to many of us. Grasping a straws won’t do it. Wether it be Jim or some other mud or not mud person, get it rebuilt not by you and let go of the stress. They’re will be something more to focus on, you know it. We all have gone through this.
Even just calling a carb specialty shop. There’s one here in CT. Guy was really cool and would have checked it out if I’d drove it to him (hour drive) but I chose to just go fully desmog carb. Once I added that thing it was like I had a brand new truck. It was so much calmer. Initially it was idling at 300, steady, so quiet I didn’t know the truck was running.
Let’s see this jacked up IM screw.Was looking at the screw this weekend and realized that I had forgotten how jacked up my old fuel mix screw was. Seems to seat and seal properly but the end was apparently broken off and then cut by the PO to be able to adjust it.
@FJ40Jim could this possibly create an issue where the high idle comes into play? Say like a small vacuum leak that is constant?
That's some nice out of the box thinking. I've mulled this around since you tagged me and the blip of the throttle is what I keep coming back to. To me it seems either mechanical or vacuum related. Like Jim mentioned above, could be a butterfly hanging up and staying open just a little. There is fore to aft movement on the shaft the butterfly valves are screwed to and really what keeps them centered in the bore is the butterfly itself. Can you see any marring or anything on the bore where maybe one is hanging up? When the high idle is happening maybe try moving the butterfly shaft fore or aft by hand and see if it drops the idle. If you just sit and let it idle high does it eventually settle back down by itself?So something that I randomly thought about yesterday was @mwebfj60 post on the secondary system for the carb. This got me thinking about my high idle issue and the fact that my secondary slow cut valve on my OEM stock carb has always had a slight leak.
After the last rebuild I did the mod where I put the white holley lighter spring in the secondary diaphragm to allow the secondary to open easier. However, I am wondering if for whatever reason my secondary slow cut system is now completely open to vacuum which is causing the system to constantly draw fuel in through the secondary system, thus creating the high idle. The momentary blip of the gas pedal would cause a drop in the vacuum that could potentially get the leak in the secondary system to then go away which allows me to go back to a "normal" idle that I have set.
@mwebfj60 @OSS @Spike Strip @FJ40Jim @CaptClose What do you guys think? Does my thought process make sense?
Your thought process is remarakably convoluted. Congratulations!
The only way to have a high idle is for something to be allowing more air & fuel into the engine. A bad PCV valve or brake booster could allow more air into engine, but with no additional fuel, the idle would be lean & stumbly.
An oversize idle jet could allow too much fuel into engine, but that would result in a loaded up, rich idle.
To get a higher idle, one of the throttle blades in the carb is not fully returning to its' hard stop. A slightly open throttle is allowing in more air, which is drawing in more fuel, feeding the engine more combustible mixture which results in more speed. Since the SSCV should prevent fuel flow in the secondary barrel, the slightly open throttle is probably the primary.