tempStrobeWylan

That makes sense. As I said before the car runs great except for carb icing around 35 F. It also got 28 mpg, which I could never attain with my other Subes. Murphy's law has kicked in. We are getting >50 F weather ever since I changed the vacuum source. Mabey I can control the weather.

Well, this is interesting to an old fart like me. I grew up in the 60's and the school of thought then was that the cooler the intake air the more dense it was. that made for more molecules per cubic inch. That was the idea behind ram induction. In fact all my Japanese car [Honda, Sub, Accura, Toyota] route the air intake from the outside so as to bypass the radiator. I have always thought that even in the winter that would be best. [the colder the better] I thought the only purpose for the heated air source would be in damp conditions. We haven't had the right damp/cool conditions here since I started trying to solve this so I cannot test whether this is fixed yet. Murphy's law.

45 to 55 F So do you mean if it's less than 100 the door draws heat from below?

I 'T'ed into the vacuum line that has 17 of vacuum and ran the thermo switch off it for a few days now. The snorkel door never changes to draw cold air. It's always drawing from the heat source. Does that mean the switch is not working? Haven't had cold weather or damp air since then so do not know if this fixed the problem. Car runs great. This motor only has just under 200k on it. Just getting started.

I lived in South Dakota during the 80's and it took over an hour driving before I could get into 5th gear when it was really cold. One night it actually got down to 60 below F. That was when I learned that mercury freezes at 40 below since the only thermometer that read it accurately was a bi-metalic spring type. The mercury ones only go to -40. I started using synthetic in the tranny and rear end. Drove like it was summertime. Things really improved when got my first 87 DL and had a better heater. Now I use Walmart's super tech Full Synthetic 75w-140. Gets better gas mileage too. I guess some cringe about the Walmart brand but I have used synthetic for decades now and this stuff seems to do me well.

So like you guys have stated, the temp switch is probably fine. Explains why changing the air cleaner housing did not fix it.

That makes sense Skip. I just bypassed the switch. There is not enough vacuum to operate the snorkel door. I measured it at 4. I then measured vacuum at the line that goes to the switch that operates the air conditioner idle speed thing. It measured 17. The thermo switch gets its vacuum from a fitting on the manifold that has a device there that I don't know the purpose of. The air cond idle switch gets its vacuum from the manifold right near the carb. Any ideas???? Tried the dry gas idea a long time ago, first before anything else (bout a year ago) tried carb cleaner too. But thanks anyway on that. I'm convinced that the fuel lines are fine. It does run like a champ in all conditions except around 35 deg F. Yesterday it was about that temp outside so I road tested it. The humidity felt dry however. Sube ran fine on the highway for a 15 mile round trip. It needs some humidity to fail. Must have to do with the snorkel motor, even though I cannot see frosting, it must be there. The cracked hose I found yesterday was not the one that goes to the switch. My mistake. I goes to the feed through fitting that supplies vacuum to the other switch inside the air cleaner, whatever that one does I do not know.

While hooking up a hose to bypass the switch I noticed the hose that supplies vacuum to the switch was badly cracked at the end. I'm bettin' that's the problem. I'm gonna change out all the hoses in that circuit. I'm thinking that the switch has to be activated by humidity rather than temp. Otherwise when you're on a dusty county road you'de suck dirt into the air cleaner and that seems contrary to Sube smarts.

Sorry folks, I tried to change my e-mail and must have fouled something up. I haven't been able to post. I e-mailed admin twice but got no answer. So I re-registered so I could let you know today I will try all of your suggestions. Thanks for all this help. I'll try to post the results.