74 Blazer K5 Flooding when warm

[Boatist]

Hi this is my first post here so let me know if I do anything wrong.
I have a 1974 blazer and have a problem with it flooding at normal temperature. I first checked the choke and it is wid open. Then I checked the temperature controled valve in the air cleaned input and it is open.

I get black smoke out of the exhaust and gas comming out the top of the carb. So I figured the float in the carburator was not shuting off fuel.
I replaced the Float with a copper one and a new needle valve and seat.

After I replace it it ran good pulling the boat about 100 miles but did die one time is stop traffic but got it restarted to finish the trip. A week at the ocean launching every day it ran perfect. Then on the trip back home made it all the way to our freeway offramp and die before we got to the light. Finally got restarted but black smoke and would hardly run the next 2 miles to the house.

Pulled the float and adjusted lower to shut fuel off sooner. Still go about 2 miles and it starts flooding again.

Anyone got any ideas???

Before this problem the truck had not been run for about 6 months.
I use it mainly to pull my 21 foot boat.

I guess should also say it is a 1974 K5 Blazer with a 350 V8.
Carburator is a Roschester 4MV California Smog.

[Schrade]

Vacuum leak?

Does it lope idle when WARM? Don't count trips at the beach - they were probably short trips...

[Boatist]

I will check for a vacuum leak. It seem fine when cold and most of the time when warm. Yes the trips to launch the boat in the Pacific Ocean and retreive were short. This Blazer has very few vaccume hoses and only one that would affect fuel is the fuel vapor canister but that is something I have not checked.
No it does not lope at idle it dies and is very hard to restart.
At full throttle will finally build some RPMS and fill the area with Black Smoke and in gear at a stop light can not keep running. Must take it out of Gear and keep RPM up then slow some and slam in gear to get going.

[Boatist]

Well I checked all the vacuum lines and all look good. It has very few.
One to the EGR valve that I plugged with a golf T.
One to the PCV valve that is in good shape.
One to the fuel canaster that is old but has no leaks.
Last one the I could not Check all the way that goes to a module on the automatic transmission but what I can see is good.

[Schrade]

Originally Posted by Boatist

Well I checked all the vacuum lines and all look good. It has very few.
One to the EGR valve that I plugged with a golf T.
One to the PCV valve that is in good shape.
One to the fuel canaster that is old but has no leaks.
Last one the I could not Check all the way that goes to a module on the automatic transmission but what I can see is good.

Double check like this:

Brick on pedal, block carb linkage, anything to get a STEADY idle. 1200rpms or so... Feed starting fluid spray, A LITTLE AT A TIME, EVERYWHERE. Rev increase is the leak. Watch that it doesn't get drawn into the carb, where air IS SUPPOSED to feed - you'll get a false positive...

In a tough spot to pinpoint? Light a book of matches, blow it out while the heads are burnin', and feed the smoke to the leak.