Engine dies when weather is wet
 

My 68 Chevy
250 6cyl
single barrel carb
HEI ign (new wires, new cap and rotor)
Stock air cleaner and filter is good, has heat tube down to manifold
Manual choke
manual trans
On my way to work about 7 miles or so about 2/3rds way there the last couple of days it has been raining or heavy fog, when I come to stop or just in neutral coasting the engine is sputtering, idling low and it will die. Starts back up OK but if I want to continue running I have to give it gas or pull choke out a bit. I cleaned the Distributor cap with electrical parts cleaner and used carb cleaner around carb and manifold. No apparent vacunm leaks. Not sure what is causing this, any help would be great.
Thanks
Ron

Re: Engine dies when weather is wet
 

You’ve got a cold intake plenum!
Check that the heat riser is working?

Re: Engine dies when weather is wet
 

BINGO we have a winner.

Re: Engine dies when weather is wet
 

The tube from air cleaner to the exhaust manifold?
Ron

Re: Engine dies when weather is wet
 

Need a pic so we can see if the air cleaner, heat stove, stove pipe, and thermac are all present. If they are and the thermac is working (check to ensure it's not sucking air through the snorkel, should be pulling it up the bottom when cold), then check the heat riser valve to ensure it's still there and operating freely.

Re: Engine dies when weather is wet
 

Look in here for a pic of the heat riser.

http://67-72chevytrucks.com/vboard/s...d.php?t=313227

Re: Engine dies when weather is wet
 

Here ya go. Thanks
Ron

Re: Engine dies when weather is wet
 

I have one like in pic but no heat coil, and it was stuck open( just like in pic) so I closed it Moved the weight to the bottom. may need to replace it
Thanks Borrowed pic from other post
Ron

Re: Engine dies when weather is wet
 

Yup, I'd replace the heat riser valve to get it working. Did closing it improve the problem though?

You don't want to leave it closed permanently, I think you can burn exhaust valves that way. So a working one is a better choice!

I'm surprised the way the snorkel is, with no valve! It just mixes some warm air in?

Re: Engine dies when weather is wet
 

No have not driven it yet. I will try to find a good one. Thanks Love you guys and this board
Ron

Re: Engine dies when weather is wet
 

If this doesn't solve your problem, I'd check for a hairline crack in the distributor cap - or just replace it and see if it helps.