Thread: C30 hard start

Originally Posted by Kansas

Sorry but only the early carbs had exposed welch plugs and even the enclosed ones that happen to seep dont cause any problem because there isnt any where for the fuel to go. The later carbs like this truck would have are enclosed, GM fixed it late 70s ish.

Kansas

True, BUT, the damn things leak fuel out over time and cause hard starts. The problem with them is you have to crank the vehicle over to refill the carb @a minute or 2, then pump the pedal to give it some gas and set the choke, then it will start.

To me (25 year mechanic), the carb needs overhaul and the trick is to use JB weld on the plugs so they do not leak. You can also just crank it for a minute or 2, then hit the peddle, leave the starter cool (@ 2 minutes) then try to start it. It should start.

Originally Posted by catfish1

Hello,
I noticed something today while looking at the carb. The in-line furl filter seems empty. Should it be? Could the fuel be slowly draining from the carb? Thanks.

Yes thats exactly what I was refering to when I posted about the early ff w/o the check valve its in there to keep fuel in the line from pump to carb.

The fact you have an inline tells me almost w/o a shadow of a doubt the in carb filter is long gone so PUT one in with a check valve and find a proper ff spring or it wont do any good I guarantee if yours was missing they left the spring out also, think about it if the inline does its job a new in carb filter wont ever get bad. Btw make sure the thin nylon seal that goes around the in carb fuel filter housing is intact very important because they usually fall off when changing a ff on the car!!!

Carbs and fuel pumps 101- the check valve started when they started putting returns on fuel pumps mid/late 70's trying to solve the vapor locking problems and that did in fact fix 95% of all cars but GM was smart enough to put the ck valve in for the hard starting problem nobody else did it.

And streeter think about the jb weld for a minuite.......what will it really do? Thay already give you a cheesy foam pad thats supposed to keep the plugs from leaking have you once studied the form and funtion of it its really pretty funny.

Kansas

Originally Posted by Kansas

Yes thats exactly what I was refering to when I posted about the early ff w/o the check valve its in there to keep fuel in the line from pump to carb.

The fact you have an inline tells me almost w/o a shadow of a doubt the in carb filter is long gone so PUT one in with a check valve. think about it if the inline does its job a new in carb filter wont ever get bad. Btw make sure the thin nylon seal that goes around the in carb fuel filter housing is intact very important because they usually fall off when changing a ff on the car!!!

Carbs and fuel pumps 101- the check valve started when they started putting returns on fuel pumps mid/late 70's trying to solve the vapor locking problems and that did in fact fix 95% of all cars but GM was smart enough to put the ck valve in for the hard starting problem nobody else did it.

And streeter think about the jb weld for a minuite.......what will it really do? Thay already give you a cheesy foam pad thats supposed to keep the plugs from leaking have you once studied the form and funtion of it its really pretty funny.

Kansas

Hello,
I'm going to give this a try as soon as possible. (install a new in line filer/w check valve). Thanks again.

Originally Posted by catfish1

Hello,
I'm going to give this a try as soon as possible. (install a new in line filer/w check valve). Thanks again.

Ok good luck you do know the filter I am refering to is in the carb right? where the fuel line attachs takes a 1" wrench that is where it is just get the filter the truck calls for at the parts house I have forgotten the number doesnt matter but they will know (only 4 total short and long with or w/o ck vlv) and dont forget the spring behind it or the ck vlv wont help you a bit.

The dynamics of the problem are air gets pulled into the fuel line around the needle seat almost immediately after the pressure drops when you shut the engine off and goes to the level the fuel is in the tank by gravity etc. hth

Kansas

Originally Posted by Kansas

Ok good luck you do know the filter I am refering to is in the carb right? where the fuel line attachs takes a 1" wrench that is where it is just get the filter the truck calls for at the parts house I have forgotten the number doesnt matter but they will know (only 4 total short and long with or w/o ck vlv) and dont forget the spring behind it or the ck vlv wont help you a bit.

The dynamics of the problem are air gets pulled into the fuel line around the needle seat almost immediately after the pressure drops when you shut the engine off and goes to the level the fuel is in the tank by gravity etc. hth

Kansas

Hello,
I know the filter you are referring to. The exploded diagram of the carb shows the internal fuel filter, but not the in-line filter. Is the in line filter something somebody else added on? I'll try and pick up a new filter tomorrow. Do you know if they are difficult to find for that age of truck? Thanks one more time.

Originally Posted by catfish1

Hello,
I know the filter you are referring to. The exploded diagram of the carb shows the internal fuel filter, but not the in-line filter. Is the in line filter something somebody else added on? I'll try and pick up a new filter tomorrow. Do you know if they are difficult to find for that age of truck? Thanks one more time.

Welcome! Yes the inline was added no question about that and no the carb filters are easy to get the spring will be another story all together you may have to either talk to a carb guy or a junkyard or improvise, its not a real stiff spring you dont want to squash the filter but it needs to be there.

Kansas

Catfish here is some pics I went and dug an old carb out for a spring and found the various filters to give you an example that is easier. let me know if you have any questions at all. hth

The check valve (a very misunderstood device) is in the second (long) filter and it faces the opening in the ff housing which is the piece on the left and the thin white seal laying there fits on the very end of the ff housing they usually fall off when changing filters they are re-useable as long as they are intact.

One more thing I will caution you about is from years of experience making my living doing this crap it doesnt pay to be sloppy believe me keep any dirt or pieces crap out of the ff housing when changing the ff or the float will stick and I mean it will flat spew fuel out the top then you have to tear it down for sure, put the carb filter in FIRST then the inline before you run it and it goes spring first in carb then filter with ck vlv out inside ff housing and dont cross thread it they easy to do that run it in with fingers until you are positive its right (the filters cant be put in backwards w/o really working at it they have a wide spot or pinch) but just so you know!!!


Kansas

Hello,
Dumped about a 1/2 to 2/3 of a small dixie cup of fuel into the carb and turned it over. Fired right up, no problem. I guess this means that the carb is draining fuel. Could be the welsh plugs or the fuel filter check valve? I now have it narrowed down, and can start the truck easily for now. A big thanks to everyone for their help.