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5.7 carb fires then dies after 1 minute

mikem40

Member
At first I was checking the elec fuel pump. (Pumps during crank but dies w/. power lost) then i had a light on the purple wire to the choke which lights when cranking but not on run. I will then lost all power to the Ing. switch & gages & the engine dies. Turn the ign. off for a moment & have power back. I must have a short somewhere I am going to check the oil sender, main fuse & engine grd. and all the wirng. Any other suggestions? TIA
Update jumped the oil presure sender & seems to be idling ok I also removed & spayed the carb. I think I may need a new ing. switch as the power is still intermentent.
Changed OP sender, It will start right up and run 1 minute & die at that time I also lose power to the gages & ing. switch. after another min I have power. Any clues?
Thanks
 
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Check the engine's main barrel plug for corrosion and tightness. Also look for loose or corroded battery cables. I once had a cracked automotive + battery cable that gave me fits.
 
Checked the main barrel plug for corrosion nice & clean
I also cleaned the engine ground. It still runs for a minute & dies. Then I also lose power at the ing. switch & gages for the next min then it works again. The trim switch on the shifter will work all the time. One side of the carb delivers fuel better than the other.maybe its time for a rebuilt but the lost of electric after stalling is baffling.
 
"Then I also lose power at the ing. switch & gages for the next min then it works again." Check wiring at the switch. Use a test light when it does not work to see if power is getting through the switch; light should be bright on bothe sides of the switch. Replace the switch if needed.

"The trim switch on the shifter will work all the time." Normal.

"One side of the carb delivers fuel better than the other.maybe its time for a rebuilt but the lost of electric after stalling is baffling." Yes it is.
 
loose shifter neutral switch, got a kill switch ?

follow the wires get to a connection clean it all do em all. start at the one lug and work all around.

Starter connections make sure you disconnect the battery before.

Ignition switch bad, connections bad.
 
When it dies on you, have you checked for spark as you try to restart it? I minute of running doesn`t seem long enough for a coil to heat up and cause an open circuit but if it was me, I`d check for spark as soon as it dies and if none, it would make me suspect the coil.
 
some throttles have kill switch built into the throttle right next to the neutral switch maybe someone installed something and put a screw thru a wire. we had a problem with a friends kill switch, was a used boat and po did just that.
 
BAD IGNITION SWITCH................

Because he loses his guages and 12 volts to the coil he is loosing his RUN circut.
then when he retries it with the key switch it does the same thing.

He either has a bad ignition switch or a bad connection at the switch.

If there is 12 volts to the key switch at all times and then when in the run position it is good to start but looses it after a second or two but 12 volts is still on the key switch , replace switch.

could be when he throttles up he is engaging the shift interutor switch due to cables being out of adjustment.




Other test to do it this, make a remote starter rig as I have drawn and disconnect the pin connector, hook this up and see if it keeps running until you flip the on off switch in the diagram also use alligator clips on the end of the wires for easy hook up to terminals.

see pic.
 
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one problem solved Found the electric problem a short in the red w/ purple wire from the slave soleniod. Now on to the next
The engine idles but the shifter is 1/4 forward & it stalls in Neutral. Is this a shift cable adjustment ( shift cable is new) or a carb problem?
Thanks for all the help
 
"maybe someone installed something and put a screw thru a wire."

Good point Chiefalen; anything is possible.
 
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