six cylinder won't start in the morning

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Mickey1977

Junior Member
Joined
Apr 16, 2024
Posts
2
Reaction score
0
Location
Plano
First Name
Mickey
Truck Year
1977
Truck Model
Custom Deluxe
Engine Size
250
I have been trying to solve why I have to pour gas into my single barrel carb on the very first start of the day. It is an inline six with a manual three speed. I have a new manual fuel pump, new fuel line from pup to carb, and new filter. After the first start it starts right up. I have a manual choke that closes the shutter on the carb properly. arfter replacing everything, it still won't fire up on first start, and cuts out at fift mile an hour. Any suggestions?
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
2,451
Reaction score
3,819
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
Let it sit overnight. Don’t move the throttle, remove the air filter housing. Once again, don’t touch the throttle, open the choke plate. Look down the throttle bore, and look at the accelerator nozzle while you move the throttle. You should see a solid stream of fuel. If not, either the carb is leaking fuel, or the accelerator pump check ball is leaking.

Inspect all the fuel lines, make sure none are cracked or dry rotted. If it’s stalling or dying at 50mph it sounds like the pump isn’t able to pull full correctly. If there is a hole in the fuel line, the pump will suck air instead of fuel.

More than likely you won’t see fuel dripping. Look for stains or discoloration around the lines, especially the clamps. The steel lines tend to corrode under the clamps.
 
Last edited:

Mickey1977

Junior Member
Joined
Apr 16, 2024
Posts
2
Reaction score
0
Location
Plano
First Name
Mickey
Truck Year
1977
Truck Model
Custom Deluxe
Engine Size
250
Rebuilt Carburetor and replaced all rubber hoses connecting steel Fuel lines. Vehicle start in the morning but stalls at 25mph in second and 35 in third. Checking the fuel lines for corrosion. Also checking the timing.
 

squaredeal91

Full Access Member
Joined
Mar 10, 2023
Posts
2,538
Reaction score
4,585
Location
Cave junction Oregon
First Name
Greg bush
Truck Year
1991 SB
Truck Model
K30
Engine Size
5.9 Cummins 12 valve
Sounds kinda like fuel starvation. Will it stay idling?
 

Rickf

Full Access Member
Joined
Jul 29, 2017
Posts
571
Reaction score
713
Location
Grafton NH
First Name
Rick
Truck Year
1974, 1954 & a 1937
Truck Model
K20
Engine Size
350
Does it sound like it cuts out at a certain engine rpm? Maybe wire in a tach to check.
 

TotalyHucked

Full Access Member
Joined
Feb 24, 2020
Posts
3,671
Reaction score
11,862
Location
Auburn, Georgia
First Name
Zach
Truck Year
1985
Truck Model
Sierra 1500
Engine Size
5.3
Also keep in mind, the pump being new means nothing these days. Could be bad out of the box
 

fast 99

Full Access Member
Joined
Dec 31, 2021
Posts
2,029
Reaction score
2,938
Location
Spokane, Washington
First Name
Brian
Truck Year
81,85
Truck Model
K20
Engine Size
350
Really can't guess when diagnosing.

I personally had 2 new fuel pumps on the same SB that worked for about 15 miles before pooping the bed.

Start with basics then move on to more obscure or expensive possibilities. Fuel, intake, compression, spark, exhaust.
 

Forum statistics

Threads
44,173
Posts
950,824
Members
36,287
Latest member
goodwrenchca
Top