Okay, I have searched threads for 3 days so that I would not bore anyone re-hashing something y'all may be tired of ... no luck. sorry, but here goes ...

I have a '70 F250 w/ a newly rebuilt 360 (less than 500 miles by reputable guys) . Everything is stock (intake, 2 bbl carb, ignition, etc) When cold, she fires up beautifully and runs flawlessly. But when I shut her down, she refuses to fire back up. I have stood on top of the truck and looked down the carb throat to check for gas. It looks like there is some getting in there, but apparently not enough. I am going to do the typical fuel troubleshoot in the a.m. but wanted to send this post out first to get any additional ideas. Is this a choke problem? Vacuum? Also noticed a little oil on top the intake behind the carb. It 'appears' to be coming out at or near the heater hose that runs under the carb/plate.

I hope this is enough info to jog someones memory. Thanks in advance for any help/advice. I am not an amateur, but definitely not a pro either.

 

that sucks bro. take the carburetor apart and check for clogs. i've had gunk get in my jets and idle circuit before. its amazing what a little particle is capable of. to check for vacuum leaks just spray wd40, water, carb cleaner, or although it can be dangerous starter fluid works the best. spray that all around the carb and intake and if the idle suddenly jumps you'll pinpoint the leak.

 

does it turn over real slow when hot. might be a timing issue

 

I believe you have the boiling the gas out concern that many have. Does your carb sit directly on the intake? I had the problem with my truck and a 4 barrel.

A 1" phenolic spacer between the carb and intake stopped the issue cold in it's tracks. I can get the truck to normal temp, stop it and refire it, before I had to grind on it a bit before it would fire again.



John

 

sorry for piggy backing on your post but I've got an issue like that too. mine dont want to start after it's been driven, but it's almost like a flooding thing cause i have to hold it to the floor and alot of black smoke only at startup. runs great -- idles great ?????????

 

Well try the spacer and report back.



John

 

Raining and nasty today so not much in the way of troubleshooting ...

jowilker, the carb now sits on a spacer that has the heater hose running 'through' it. I assumed this was to cool the carb down as well. Is this correct? Should I try an additional spacer (seems like too much) or maybe reroute the water around the carb with the phenolic one you mention.

todd31277 ... nope. she turns over like she is ready to fire right back up. as a matter of fact, if I IMMEDIATELY crank her up after I shut her down, she fires right back up.

also checked the choke and it is opening and closing, BUT I am not so sure that it closes 'all the way' as a manual I have suggests.

thanks all!

 

With the heater block there should also me a 1/4" pholenic spacer between it and carb.

 

Nifty, Your plate is actually there to heat the carb, rather than cool it. I don't use it on my truck, although I have a couple three of them somewhere. The alum spacer can transfer heat to the carb, and the (plastic or) phenolic does not.

I went from having your issues to not by using the spacer. I have run 2 1" spacers with no problems.


John

 

Nifty,
If you are still running stock ignition, try changing the condensor. This is often overlooked but a condensor is simply a capacitor and when a capacitor gets weak it can malfunction with the extra heat buildup after the engine sits for a few minutes after shutdown. Also check your dwell on the points (point gap if you don't have a tach/dwell meter). I realize that with a fresh rebuild, the points and condensor are probably "new", but good ones are getting harder to find with all the foreign crap on the market. I had the rubbing block on a set of @#$%^& brand points wear down in less than 500 hundred miles to the point where my truck wouldn't even start!!! My preference for points/condensor sets is Standard "Blue Streak". Car Quest sells them under their own packaging but just ask for "Blue Streak".
Oil on the intake is likely a valve cover gasket leak.
Good luck,
Gene

 

did that offset your kickdown linkage or throttle at all? i am worried about things
not wanting to line up.

 

Gene, Good point, what what if you have a hot electronic ign. setup and this is happening?
Sometimes your points setting can slip and just need to be reopened to get you on your way again.


Dave, I have a home made throttle cable holder that is a lot taller than the original. The hollow kick downs are very bendable.


John

 

what should i get 1/2 inch, 1 inch, 4 hole, or an open one?

 

4 hole to match your carb pattern, 1" thick

 

my dad was telling me sometimes what also can cause this is the nozzles that are attached to the floats dont always shut all the way and when you turn the truck off the little bit of pressure still coming in the fuel inlet is enough to squirt just enough fuel through the jets to cause sortof a flooding condition when you go to start it back up.