My car ran and idled fine a couple of days ago when the temperature was in the mid 50's and 60's. Drove to work and then temp dropped to around 30 and the car wouldnt idle anymore. It drives fine but it just wouldnt idle. I checked for vacuum leaks and didnt find any, checked the fuel system everything is fine and i did a search but i couldnt find anything about whether or not the carb needed to be tuned for winter time. Do i need to tune the carb to run rich or is this a common problem with a common fix. Thanks

 

Check the shutter valve (search) otherwise how old are your plugs and wires

 

yes, it needs to be retuned for the weather. really all you need to do is adjust your richness and idle speed.

 

i cant edit...idk why but, i think i should tell you that i find your signature to be humoruous, and do tell how you got 8 fuel filters for 20 bucks.

 

No winter tuning needed, hell, my Mikuni started when it 16* the other day. You may have a moisture problem in the fuel system, try a can of HEET.

If you've gone through all 8 of those fuel filters listed in your sig, you probably need to drop the fuel tank and clean it. If it's full of crud and any of it got past the filter, the carb probably needs gone through.

 

How did you get a fuel pump for $30?

 

My esteemed collegue is correct. Is your choke operating correctly also?

 

If your carb/intake are stock,be sure your thermostatic aircleaner valve is working and hooked up.Thats the flapper in the intake snorkle and the aluminum hose that leads to the exhaust manifold heat shield.
Your symptoms sound exactly like when I ran my smog-stripped Yaw Nikki back in the days.I had no thermal intake system and my primary venturies would freeze up solid in the morning,even if it was a bit above freezing outside.It would rev and run fine,but refused to idle,even when warmed up.....the ice would just block the hell out of the idle and transition fuel holes.I confirmed the ice a few times as I coasted off the freeway offramp with a dead engine.Pulled the aircleaner lid off and BAM!!.....two yellowish white globs of ice in both primary barrels.I pulled my cold air intake off, hooked the aluminum hose back up to the snorkle and ran the other end down next to my headers.Even with the flapper door gone,it was enough to keep my carb from icing for the rest of the season.

If your carb isnt stock or the thermal aircleaner junk is gone/removed,just try to find a way to feed the engine some warm underhood air in the cold winter months.......yea you wont make as much HP with hot air,but an engine that wont run makes 0 HP.

 

what about the channels in the manifold for coolant, isnt that there to prevent carb icing..?

 

That works fine for the lower part of the carb, but doesn't get the heat to the upper parts that Steve was refering too. The intake runners on my Mikuni were ice cold on 80* days, sitting at idle. That's how much cooling power gas can have when it changes states from fuel to vapor.

 

Trochoid, You got that right. The Mikuni intake will chill a beer in the summertime.

 

cool, im glad you guys are setting me straight. i was under the impression that you would need a re-tune, seen as how quads and snowmobiles need to change jets when the weather changes.

 

I worked at Oreilly auto and i could get them for 98 cents at my discount. But i switched over to Advance auto and now its like $1.50.

 

again i worked at Oreilly Auto Parts and with the discount it was like $30. Its only around 40 without it so if you want the part number just let me know and ill get it to you. The universal ones at Advance are about 60 so you can get that part number and cross it over at Oreillys and they should have a couple in stock for around 40 dollars.