having some engine trouble - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Lightspeed · 10-20-2002, 08:08 PM

the truck has a 70 350. LT1 bottom end, with 300 heads(someone care to elaborate on what 300 heads are?) a wiend intake and an edelbrock four barrel with electric choke. anyways the motor will fire but wont' stay running. it bogs way down backfires and dies. if i give it a lot of gas i see two little streams of gas come out of the carb. the last time i tried to start it these streams ingnited causing a nice little fireball. its running really rich and i was wondering if someone could tell me if my problem could be fixed by adjusting the carb and if so could tell me how to adjust it. thanks in advance.

Capitol68 · 10-20-2002, 08:14 PM

Have you done any timing work on it ? Pulled the dist and restabbed ? Is it in a truck that has been running and suddenly started this ? Need a little more info

Lightspeed · 10-20-2002, 08:23 PM

the guy i bought it from said the timing needed to be adjusted, it has been doing this since i bought it but now it won't even idle. also the choke linkage is broken so the choke either hangs wide open or completely shut.

bigjimzlll · 10-20-2002, 08:50 PM

first things first...fix the choke(tie it open) pull a spark plug and see what it looks like(probably fouled) change if needed...triple check the plug wires are ran right(especially 5+7) pull the cap..check for carbon traces or cracks..replace if needed..rotor too.is this an HEI? if not check points and replace if needed,,now start engine...if it doesn't start now.come back and tell us whats up..

Lightspeed · 10-20-2002, 09:09 PM

ok, but does anyone have any idea about the fuel spraying out of the carb? its goes up like a foot in the air.

my new 72 · 10-20-2002, 09:49 PM

What kind of fuel pump are you running? It sounds like the float is stuck down flooding the carb and shooting out of the jets hard enough to splach back up like a water gun. This would only be true if you had an electric fuel pump or one he!! of a mechanical one. Take the lid off the carb and see if the bowls are gummed up or if the float has a hole it it.

mikep · 10-20-2002, 09:49 PM

It sounds like you ( your engine ) are really retarded. Have you checked the timing yet?

Lightspeed · 10-20-2002, 10:31 PM

its a mechanical pump, how do you fix the float, or more importantly how do you find it? and im pretty sure the timing is off, im more worried about the carb right now cuz im afraid its gonna start a major fire.

bigjimzlll · 10-20-2002, 10:44 PM

go to www.edelbrock.com look in their manual for a 1406 carb.it will show an exploded view..its real simple to work on..I think 7 screws and pull off the top..there os some linkage to remove..dont lose the little clips

mikep · 10-20-2002, 11:12 PM

Your incorrectly set timing is causing the carburetor reversion. If you set the timing at its static point then you should get it in ballpark. turn the engine over by hand until its at 10 degrees before top dead center, turn the key on but do not engage the starter, turn the distributor until the spark plug fires either by looking at the timing light or just by puling the wire and watching it spark to ground. lock the distributor down. start the truck then adjust the timing while its running. voila

Lightspeed · 10-20-2002, 11:20 PM

mikep-i dont know a whole lot about motors, could you go through that step by step, like how do i get the engine at ten degrees before top dead center and how do i get the distributor loose from the block to turn it. im sorry if all these questions sound stupid but this is my first project and i've never really had anybody to show me how to do these things.

bigjimzlll · 10-20-2002, 11:44 PM

everyone had to start some where....the pulley where the fan belt goes on..the bottom one..is attached to the harmonic dampner...on the dampner there will be a groove cut across the outside ring...on the drivers side of the motor..at about 2 oclock looking at the front of the motor will be the timing tab....you will have to clean it real well..it has marks on it and numbers...you line the groove from the harmonic dampner with the 5th mark on the timing tab...BTDC..now its a 50-50 chance that you will be on the right compression stroke...so if it dosent work(start) rotate the engine 360 degrees and try again...at the bottom of the distributor their will be a clamp with a 9/16 bolt holding it...just loosen it enuff to turn the whole distributor

10-20-2002, 08:08 PM	#1
Lightspeed Registered User Join Date: Oct 2002 Location: Virginia Posts: 226	having some engine trouble the truck has a 70 350. LT1 bottom end, with 300 heads(someone care to elaborate on what 300 heads are?) a wiend intake and an edelbrock four barrel with electric choke. anyways the motor will fire but wont' stay running. it bogs way down backfires and dies. if i give it a lot of gas i see two little streams of gas come out of the carb. the last time i tried to start it these streams ingnited causing a nice little fireball. its running really rich and i was wondering if someone could tell me if my problem could be fixed by adjusting the carb and if so could tell me how to adjust it. thanks in advance.

10-20-2002, 08:14 PM	#2
Capitol68 Registered User Join Date: Sep 2002 Location: Austin,Tx Posts: 327	Have you done any timing work on it ? Pulled the dist and restabbed ? Is it in a truck that has been running and suddenly started this ? Need a little more info __________________ '68 Fleet LWB orig 307 .030 over GM Hei/w Accel Super coil orig. stock TH 400. _______________________ “What we do for ourselves dies with us. What we do for others and the world remains and is immortal.” Albert Pine English author d.1851

10-20-2002, 08:50 PM	#4
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	first things first...fix the choke(tie it open) pull a spark plug and see what it looks like(probably fouled) change if needed...triple check the plug wires are ran right(especially 5+7) pull the cap..check for carbon traces or cracks..replace if needed..rotor too.is this an HEI? if not check points and replace if needed,,now start engine...if it doesn't start now.come back and tell us whats up.. __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

10-20-2002, 09:49 PM	#6
my new 72 faster, faster, faster Join Date: Dec 2001 Location: Houston ,Texas ,USA Posts: 1,354	What kind of fuel pump are you running? It sounds like the float is stuck down flooding the carb and shooting out of the jets hard enough to splach back up like a water gun. This would only be true if you had an electric fuel pump or one he!! of a mechanical one. Take the lid off the carb and see if the bowls are gummed up or if the float has a hole it it. __________________ I'm going to Law School, wanna debate? It's good practice.

10-20-2002, 09:49 PM	#7
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	It sounds like you ( your engine ) are really retarded. Have you checked the timing yet? __________________ No truck :-(

10-20-2002, 08:23 PM	#3
Lightspeed Registered User Join Date: Oct 2002 Location: Virginia Posts: 226	the guy i bought it from said the timing needed to be adjusted, it has been doing this since i bought it but now it won't even idle. also the choke linkage is broken so the choke either hangs wide open or completely shut.

10-20-2002, 09:09 PM	#5
Lightspeed Registered User Join Date: Oct 2002 Location: Virginia Posts: 226	ok, but does anyone have any idea about the fuel spraying out of the carb? its goes up like a foot in the air.

10-20-2002, 10:31 PM	#8
Lightspeed Registered User Join Date: Oct 2002 Location: Virginia Posts: 226	its a mechanical pump, how do you fix the float, or more importantly how do you find it? and im pretty sure the timing is off, im more worried about the carb right now cuz im afraid its gonna start a major fire.

10-20-2002, 10:44 PM	#9
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	go to www.edelbrock.com look in their manual for a 1406 carb.it will show an exploded view..its real simple to work on..I think 7 screws and pull off the top..there os some linkage to remove..dont lose the little clips __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

10-20-2002, 11:12 PM	#10
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Your incorrectly set timing is causing the carburetor reversion. If you set the timing at its static point then you should get it in ballpark. turn the engine over by hand until its at 10 degrees before top dead center, turn the key on but do not engage the starter, turn the distributor until the spark plug fires either by looking at the timing light or just by puling the wire and watching it spark to ground. lock the distributor down. start the truck then adjust the timing while its running. voila __________________ No truck :-(

10-20-2002, 11:20 PM	#11
Lightspeed Registered User Join Date: Oct 2002 Location: Virginia Posts: 226	mikep-i dont know a whole lot about motors, could you go through that step by step, like how do i get the engine at ten degrees before top dead center and how do i get the distributor loose from the block to turn it. im sorry if all these questions sound stupid but this is my first project and i've never really had anybody to show me how to do these things.

10-20-2002, 11:44 PM	#12
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	everyone had to start some where....the pulley where the fan belt goes on..the bottom one..is attached to the harmonic dampner...on the dampner there will be a groove cut across the outside ring...on the drivers side of the motor..at about 2 oclock looking at the front of the motor will be the timing tab....you will have to clean it real well..it has marks on it and numbers...you line the groove from the harmonic dampner with the 5th mark on the timing tab...BTDC..now its a 50-50 chance that you will be on the right compression stroke...so if it dosent work(start) rotate the engine 360 degrees and try again...at the bottom of the distributor their will be a clamp with a 9/16 bolt holding it...just loosen it enuff to turn the whole distributor __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.