Gary Lewis Posted May 3, 2020 Share Posted May 3, 2020 You are all so very helpful, thank you. Of course I will be DYI-ing a smoker right away and will post an update. Do you have a cigar? http://forum.garysgaragemahal.com/Vacuum-leak-detection-effective-and-inexpensive-td11511.html Link to comment Share on other sites More sharing options...
Starliner Posted May 4, 2020 Author Share Posted May 4, 2020 Do you have a cigar? http://forum.garysgaragemahal.com/Vacuum-leak-detection-effective-and-inexpensive-td11511.html Well, I went the DYI route. Burned my hand on the can, (of course), but I had smoke coming out of this valve before the PCV. This becomes another What's This? When the lever faces one way, outside air can enter, the other way, SOME air enters. What the heck is it? I am sniffing down a rough idle but really, it looks like it is flooding at idle. I am 2-footing it now and tonight even had run it with the air cleaner off to get her home. I bet I need to adjust those hard to get idle mix screws. Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 4, 2020 Share Posted May 4, 2020 Well, I went the DYI route. Burned my hand on the can, (of course), but I had smoke coming out of this valve before the PCV. This becomes another What's This? When the lever faces one way, outside air can enter, the other way, SOME air enters. What the heck is it? I am sniffing down a rough idle but really, it looks like it is flooding at idle. I am 2-footing it now and tonight even had run it with the air cleaner off to get her home. I bet I need to adjust those hard to get idle mix screws. I have no idea what that valve is. I've never seen one and it isn't supposed to be there. I'd put a new PCV hose on and ditch the valve. As for the idle, it may be the idle air screws, but I'm betting you have a blown power valve. Link to comment Share on other sites More sharing options...
Starliner Posted May 4, 2020 Author Share Posted May 4, 2020 I have no idea what that valve is. I've never seen one and it isn't supposed to be there. I'd put a new PCV hose on and ditch the valve. As for the idle, it may be the idle air screws, but I'm betting you have a blown power valve. Geeze, I just rebuilt it so I will go to mix screws first. Thanks Gary. Link to comment Share on other sites More sharing options...
grumpin Posted May 4, 2020 Share Posted May 4, 2020 I have no idea what that valve is. I've never seen one and it isn't supposed to be there. I'd put a new PCV hose on and ditch the valve. As for the idle, it may be the idle air screws, but I'm betting you have a blown power valve. I’d ditch the valve too, but I would like to know what it is for! Link to comment Share on other sites More sharing options...
Gearhead Posted May 14, 2020 Share Posted May 14, 2020 I have no idea what that valve is. I've never seen one and it isn't supposed to be there. I'd put a new PCV hose on and ditch the valve. As for the idle, it may be the idle air screws, but I'm betting you have a blown power valve. That valve is factory. The explanation I received, decades ago, was that it was emission related. Can't remember specifically what it did. It can go. Link to comment Share on other sites More sharing options...
myrl883 Posted May 15, 2020 Share Posted May 15, 2020 That valve is factory. The explanation I received, decades ago, was that it was emission related. Can't remember specifically what it did. It can go. It's called a hot idle compensator. Under high under hood heat conditions (traffic), the bi-metal spring opens the valve to create a slight vacuum leak that leans the idle mixture and raises idle speed slightly. Pretty clever engineering for the 60's, before we had electric throttle kickers! Personally, if it works properly, I would NOT eliminate it. And, sorry Gary, but that's exactly where it belongs. Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted May 15, 2020 Share Posted May 15, 2020 It's called a hot idle compensator. Under high under hood heat conditions (traffic), the bi-metal spring opens the valve to create a slight vacuum leak that leans the idle mixture and raises idle speed slightly. Pretty clever engineering for the 60's, before we had electric throttle kickers! Personally, if it works properly, I would NOT eliminate it. And, sorry Gary, but that's exactly where it belongs. So this is something that causes a bigger vacuum leak than the PCV itself? Isn't the TVS in the distributor advance line a better solution to the issue? Link to comment Share on other sites More sharing options...
Gary Lewis Posted May 15, 2020 Share Posted May 15, 2020 It's called a hot idle compensator. Under high under hood heat conditions (traffic), the bi-metal spring opens the valve to create a slight vacuum leak that leans the idle mixture and raises idle speed slightly. Pretty clever engineering for the 60's, before we had electric throttle kickers! Personally, if it works properly, I would NOT eliminate it. And, sorry Gary, but that's exactly where it belongs. I sit corrected. Good to know. Thanks, guys. Link to comment Share on other sites More sharing options...
1986F150Six Posted May 15, 2020 Share Posted May 15, 2020 It's called a hot idle compensator. Under high under hood heat conditions (traffic), the bi-metal spring opens the valve to create a slight vacuum leak that leans the idle mixture and raises idle speed slightly. Pretty clever engineering for the 60's, before we had electric throttle kickers! Personally, if it works properly, I would NOT eliminate it. And, sorry Gary, but that's exactly where it belongs. This was found with a search [Mike's carburetors]: Hot Idle Compensator by Mike | posted in: carburetor | 0 The Hot Idle Compensator is used on some carburetors to offset enriching effects caused by percolation during hot operation. Generally used on vehicles with air conditioning. When the engine is running hot and then stopped, the fuel can boil or percolate and vaporize causing a rich condition at idle. Some Hot Idle Compensators were mounted to the carburetor: And something else: https://secure.cougarpartscatalog.com/valve-hot-air-compensator-used-1967-1968-mercury-cougar-/-1964-1968-ford-mustang.html https://www.ebay.com/itm/64-65-66-67-68-Mustang-Galaxie-Fairlane-Torino-289-260-390-hot-idle-compensator/124144270652?hash=item1ce7933d3c:g:CjEAAOSw2d5ei1zc Apparently, GM used similar technology: https://www.ebay.com/itm/GM-Compensator-CarbAirator-Add-On-Hot-Idle-Vintage-Carburetor-NOS-RP-555/184249404361?hash=item2ae61ecbc9:g:AnUAAOSwov5ekheh Link to comment Share on other sites More sharing options...
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