350 wont start I believe it's a carburetor issue

[Bamaboi23]

Hey guys new to the forum i need help i have a 90s k5 blazer had to put a new 350 bc old one got messed up I bought a used 350 crate with a quadrajet on top well I installed it made sure fuel pump was working electrical it is and got it in time wired the distributor seemed to wanna try to start i pour gas straight into carb nothing before I got the timing right it back fired now it sounds like it wants to start I pulled the inlet filter out it was very dirty not even yellow anymore then engine did sit a couple of years pulled out of a wrecked square body I'm thinking since I'm getting fire and gas to the inlet i have a carburetor issue also I'm not sure about the vacuum lines most were already connected but some on the front aren't any suggestions thanks for the help

 

[rampage]

Hey guys new to the forum i need help i have a 90s k5 blazer had to put a new 350 bc old one got messed up I bought a used 350 crate with a quadrajet on top well I installed it made sure fuel pump was working electrical it is and got it in time wired the distributor seemed to wanna try to start i pour gas straight into carb nothing before I got the timing right it back fired now it sounds like it wants to start I pulled the inlet filter out it was very dirty not even yellow anymore then engine did sit a couple of years pulled out of a wrecked square body I'm thinking since I'm getting fire and gas to the inlet i have a carburetor issue also I'm not sure about the vacuum lines most were already connected but some on the front aren't any suggestions thanks for the help

I have one suggestion for now: proofread your post and add some punctuation. Hate to be the grammar police, but when people have a hard time reading what you wrote or can’t make sense of it then they’ll tend to not read it. Help us help you.

 

[Scribbles]

Are you running a mechanical fuel pump or using the factory in tank pump?
Your fuel pump in tank will provide too much fuel pressure and you need a regulator installed to bring the fuel pressure down to a max of 8psi.
If you are using a mechanical pump with the in tank disabled then it’s possible you are flooding it out by adding the extra gas in by hand.

If the fuel pump situation that I mentioned above is in order I would pull the #1 plug, make sure your at TDC compression stroke, verify balancer is at 0. verify the distributor is on #1 and then I would reinstall the cap, hook a timing light to #1 plug wire, try and start it. If it doesn’t even try to fire but you have spark (verified w/ timing light) I’d try using a can of starting fluid or carb cleaner to mist the carb and see if it’s a fuel issue and work forward from that point.

 

[Bamaboi23]

Are you running a mechanical fuel pump or using the factory in tank pump?
Your fuel pump in tank will provide too much fuel pressure and you need a regulator installed to bring the fuel pressure down to a max of 8psi.
If you are using a mechanical pump with the in tank disabled then it’s possible you are flooding it out by adding the extra gas in by hand.

If the fuel pump situation that I mentioned above is in order I would pull the #1 plug, make sure your at TDC compression stroke, verify balancer is at 0. verify the distributor is on #1 and then I would reinstall the cap, hook a timing light to #1 plug wire, try and start it. If it doesn’t even try to fire but you have spark (verified w/ timing light) I’d try using a can of starting fluid or carb cleaner to mist the carb and see if it’s a fuel issue and work forward from that point.

Are you running a mechanical fuel pump or using the factory in tank pump?
Your fuel pump in tank will provide too much fuel pressure and you need a regulator installed to bring the fuel pressure down to a max of 8psi.
If you are using a mechanical pump with the in tank disabled then it’s possible you are flooding it out by adding the extra gas in by hand.

If the fuel pump situation that I mentioned above is in order I would pull the #1 plug, make sure your at TDC compression stroke, verify balancer is at 0. verify the distributor is on #1 and then I would reinstall the cap, hook a timing light to #1 plug wire, try and start it. If it doesn’t even try to fire but you have spark (verified w/ timing light) I’d try using a can of starting fluid or carb cleaner to mist the carb and see if it’s a fuel issue and work forward from that point.

Hey bud yea I did have that issue before. I took the fuel pump out of the tank because it was fuel injected. So I did put a low pressure electrical fuel pump on the rail. I turn the engine by hand with the number 1 spark plug out and felt compression. Then I did turn it to zero. After that i put the distributor on and wired it up in the firing order. I havnt tried starter fluid just gas into the top of carb. I'm not sure maybe I did something wrong but I dont have a timing light I did have a spark tho. I took the wire off and had someone bump it and I had a spark.

 

[Wes Harden]

You can block all the vacuum ports. Until it runs.You only need the vac advance, power brake booster, and pcv.
Did you replace/modify the in tank
Pick up when pump was removed?
Ok so what style pump and where is it installed? Should be as close to tank and as low as possible. How much gas is in tank, how old?
It would not surprise me if the carb had plugged passages, or a needle and seat, float issue. The crap gas we have today is hard on carbs.
If fuel flooded you will need to pull the plugs and crank it over to blow it out. Plugs might even need to be replaced.
Good luck and welcome to the board

 

[Bamaboi23]

You can block all the vacuum ports. Until it runs.You only need the vac advance, power brake booster, and pcv.
Did you replace/modify the in tank
Pick up when pump was removed?
Ok so what style pump and where is it installed? Should be as close to tank and as low as possible. How much gas is in tank, how old?
It would not surprise me if the carb had plugged passages, or a needle and seat, float issue. The crap gas we have today is hard on carbs.
If fuel flooded you will need to pull the plugs and crank it over to blow it out. Plugs might even need to be replaced.
Good luck and welcome to the board

Thanks man glad to be a part of chevy forum. I didn't change the tank all I did was pull the old sending unit out and remove the pump I put a longer hose where the pump was to extend to the bottom of the tank. It had really old gas. I removed the hose from the carb and connected the fuel pump so the old gas would run into an old gas can. Then put alittle new gas no ethanol into the tank. I did pull the number one plug and it was alittle dirty. All the plugs and wire were new a few months ago but the gas was very old.

 

[diesel4me]

It is rare for a carb to prevent an engine from starting,it would have to plug up practically solid --it may cause poor running or stalling,or flood from a stuck needle valve or float that sank,but you still should be able to get the engine to fire up and run briefly on the gas you poured down the intake..

If it wont do that and you have good spark and it is timed even close to TDC or the specified setting, its probably flooded..
As noted ,on HEI it is not hard to flood the plugs so bad the engine wont even attempt to fire up till good or new plugs are installed..

 

[Bamaboi23]

It is rare for a carb to prevent an engine from starting,it would have to plug up practically solid --it may cause poor running or stalling,or flood from a stuck needle valve or float that sank,but you still should be able to get the engine to fire up and run briefly on the gas you poured down the intake..

If it wont do that and you have good spark and it is timed even close to TDC or the specified setting, its probably flooded..
As noted ,on HEI it is not hard to flood the plugs so bad the engine wont even attempt to fire up till good or new plugs are installed..

That's what I was thinking it should at least try to start. I'm gonna take the plugs out and clean them. I've got a 56 chevy truck that has a qjet. A guy messed with my vaccum plugs and it didn't run anymore inhad to try and try and try to turn it over and it would finally run. I'm gonna mess with it today when my boy gets outta school.

 

[diesel4me]

Sometimes once the plugs get gas fouled they will never fire again under compression..they may appear to have great spark outside of the engine,but they get damaged once enough gas floods them internally,the spark jumps from the center electrode thru the ceramic insulator up inside the shell under the compression in the cylinder ,instead of at the electrode tips ..

GM vehicles that used HEI in the early years had issues with the plugs fouling after a cold start--GM thought they could use plugs with gaps as wide as .080 ,to lower emissions and bet a better "burn",but on cold mornings ,if you pumped the gas pedal more than it wanted,or the choke pull off didn't open the choke far enough,the engine would stall and you could crank it till the battery went dead and it would not even fart..till new plugs were installed,then it'd fire up instantly..

They decided to go no wider than .045 on the gaps after that..(1976 I think)...
I have noticed Champion plugs seem to die permanently after being gas flooded,AC & Autolite's sometimes will allow it to re-start once the excess gas evaporates..you might be able to burn them clean with a propane torch and try them if you do not want to spend money on new plugs..

 

[Bamaboi23]

Sometimes once the plugs get gas fouled they will never fire again under compression..they may appear to have great spark outside of the engine,but they get damaged once enough gas floods them internally,the spark jumps from the center electrode thru the ceramic insulator up inside the shell under the compression in the cylinder ,instead of at the electrode tips ..

GM vehicles that used HEI in the early years had issues with the plugs fouling after a cold start--GM thought they could use plugs with gaps as wide as .080 ,to lower emissions and bet a better "burn",but on cold mornings ,if you pumped the gas pedal more than it wanted,or the choke pull off didn't open the choke far enough,the engine would stall and you could crank it till the battery went dead and it would not even fart..till new plugs were installed,then it'd fire up instantly..

They decided to go no wider than .045 on the gaps after that..(1976 I think)...
I have noticed Champion plugs seem to die permanently after being gas flooded,AC & Autolite's sometimes will allow it to re-start once the excess gas evaporates..you might be able to burn them clean with a propane torch and try them if you do not want to spend money on new plugs..

I'll just get some new plugs thanks man.ill keep yall posted

 

[Bamaboi23]

Update changed the plugs and tried to again nothing. Same ole thing feeling defeated at the moment. I'm gonna give it a break do the timing again. Another thing I put a clear filter before the carb took the inlet filter out. The pump did pump into the filter but seemed like it didnt flow thro the filter. Like just almost enough to fill it but no further. I had it the right way too maybe pump is going bad. Used starter fluid this time.

 

[Wes Harden]

starting fluid you say, it should have tried to run. where the old plugs wet ? Yeah double check your timing. when you have the dist set tdc #1, with wire off #1 plug. Old plug in #1 wire, grounded, key on turn slowly dist in clockwise till you see a spark, then counterclockwise just a small bit, snug it down. You should be very close on timing to start and run.

 

[Bamaboi23]

starting fluid you say, it should have tried to run. where the old plugs wet ? Yeah double check your timing. when you have the dist set tdc #1, with wire off #1 plug. Old plug in #1 wire, grounded, key on turn slowly dist in clockwise till you see a spark, then counterclockwise just a small bit, snug it down. You should be very close on timing to start and run.

Yea some of the plugs were nasty and wet black smut looking stuff.

 

[Scribbles]

I’m a big fan of checking and being 100% that the distributor isn’t 180 degrees off. It’s a very easy thing to accidentally stab it wrong.

 

[Bamaboi23]

I’m a big fan of checking and being 100% that the distributor isn’t 180 degrees off. It’s a very easy thing to accidentally stab it wrong.

I didnt put it in so how do I take it out and check?

 

[Scribbles]

No need to pull it. Just remove #1 spark plug and cover the hole with a finger, use a starter button or a friend to bump the motor over until you feel it start the compression stroke and then watch the balancer to come up to 0. Mark which post on the distributor is #1 plug wire then pull the cap and make sure the pointer is on or close to the post you have the #1 plug wire on.

I would pull the #1 plug, make sure your at TDC compression stroke, verify balancer is at 0. verify the distributor is on #1 and then I would reinstall the cap, hook a timing light to #1 plug wire, try and start it. If it doesn’t even try to fire but you have spark (verified w/ timing light) I’d try using a can of starting fluid or carb cleaner to mist the carb and see if it’s a fuel issue and work forward from that point.

 

[Bamaboi23]

No need to pull it. Just remove #1 spark plug and cover the hole with a finger, use a starter button or a friend to bump the motor over until you feel it start the compression stroke and then watch the balancer to come up to 0. Mark which post on the distributor is #1 plug wire then pull the cap and make sure the pointer is on or close to the post you have the #1 plug wire on.

Oh yea I did that I'm going to get again. It was close I dis put it on zero. It was pointing that way but I didnt think it was exact so I moved the pointer by hand.

 

[Scribbles]

You have to loosen the distributor clamp and rotate the base of the distributor to change timing, if you’re positive you’re at 0 turn it counterclockwise just a hair so you’re putting a little timing into it, however with it at 0 it should probably be trying to do something.

While you’re at it check plug wires and make sure they’re in the right firing order, also make sure your cranking battery is charged up and passes a load check.

 

[Bamaboi23]

You have to loosen the distributor clamp and rotate the base of the distributor to change timing, if you’re positive you’re at 0 turn it counterclockwise just a hair so you’re putting a little timing into it, however with it at 0 it should probably be trying to do something.

While you’re at it check plug wires and make sure they’re in the right firing order, also make sure your cranking battery is charged up and passes a load check.

Thanks paul will do thanks for the help.

 

[trukman1]

Pouring gas into the carb can only work for a few tries. Remember, all that gas is running past your rings into your oil. Like Scibbles said, starter fluid! Did you look into the carb to see if gas was being injected into the engine? Beauty of a carb is you can see it squirting inside the carb.