1960 GMC 305A v6 hard to start

[AngryPirate]

So, I'll have the battery at full charge and it may have been running 2 hours before, but I still need to either put the charger on "boost" mode or/and get a boost from another running vehicle.
I know it's a big engine, but man, it should be able to start more easily than this.
Perhaps the starter is bad and drawing too much juice to work efficiently?
I've re-polarized the electrical system as well.

I am forever having to spray quick start or dribble gasoline into the carb while trying to start it with a boost

I'm at my wits end trying to figure this one out.
Would finding a higher torque starter be something to consider?

There doesn't seem to be a short anywhere on the chassis (I tested for this).

So here's what I've done so far:

- had the generator rebuilt
- new AGM battery (775 CCA; 140 MIN RC at 25A)
- new cap & rotor
- replaced points with Pertronix Ignitor II
- new OE ignition coil
- replaced started with rebuilt OE starter
- new OE fuel pump
- new wires
- new fuel tank & filter
- new OE voltage regulator

I really shouldn't have to use anything outside of what was OE just to get it to start fairly regularly, I would think.

Thanks for any ideas to try.

[jbgroby]

Pirate, you might want to post this over on the national 60-66 GMC BB as well. Here is the link.

http://6066gmcclub.com/

[jbgroby]

If my 305 sits about 2 weeks, it is a bit hard to start as well, I give it a shot of starting fluid too.

Originally Posted by AngryPirate

So, I'll have the battery at full charge and it may have been running 2 hours before, but I still need to either put the charger on "boost" mode or/and get a boost from another running vehicle.
I know it's a big engine, but man, it should be able to start more easily than this.
Perhaps the starter is bad and drawing too much juice to work efficiently?
I've re-polarized the electrical system as well.

I am forever having to spray quick start or dribble gasoline into the carb while trying to start it with a boost

I'm at my wits end trying to figure this one out.
Would finding a higher torque starter be something to consider?

There doesn't seem to be a short anywhere on the chassis (I tested for this).

So here's what I've done so far:

- had the generator rebuilt
- new AGM battery (775 CCA; 140 MIN RC at 25A)
- new cap & rotor
- replaced points with Pertronix Ignitor II
- new OE ignition coil
- replaced started with rebuilt OE starter
- new OE fuel pump
- new wires
- new fuel tank & filter
- new OE voltage regulator

I really shouldn't have to use anything outside of what was OE just to get it to start fairly regularly, I would think.

Thanks for any ideas to try.

[AngryPirate]

Originally Posted by jbgroby

If my 305 sits about 2 weeks, it is a bit hard to start as well, I give it a shot of starting fluid too.

Thanks for that bit of info. I wish mine took 2 weeks of sitting before it's hard to start. Some times it won't even start if I try immediately after shutting it off.

[jbgroby]

normally, these fire up within a 1/2 second of the start IF WARM, You have replaced everything but the carb. what are you running? sure its don't have a needle valve or other small part getting stuck?

[AngryPirate]

Originally Posted by jbgroby

normally, these fire up within a 1/2 second of the start IF WARM, You have replaced everything but the carb. what are you running? sure its don't have a needle valve or other small part getting stuck?

Stock Holley carb. It's been rebuilt (by me), so that could be an issue. It does run decently once started.

[jbgroby]

Single 1902 model or a dual?

[AngryPirate]

Originally Posted by jbgroby

Single 1902 model or a dual?

I believe it's a single and 1902 or 1901 sounds familiar (the truck isn't near me atm).

[slorio]

Pirate:
A few things to check:
* Ignition timing to make sure it is on spec.
* Choke to make sure it is closing all the way.
* Accelerator pump. Take off air cleaner and open throttle while you look down carb with a flashlight. Make sure you have a nice pump shot of gas in the carb throat after it has sat overnight. If not, then you are cranking to get gas back to fill the carb bowl before you have a chance to start. Bad accelerator pump or gas leaking into engine from float bowl could be causes.

These V6's seem to like to be rich to fire up after they have sat for a while. I close choke all the way pump accelerator pump a couple of times and crank a bit. If it doesn't light off, I stop, pump accelerator again a couple of times and repeat. If it has sat for a week, it takes a few round of this to light off.

Hope this helps.
Regards,
Steve
New Orleans

[dmacs66gmc]

Mine was doing the same thing as yours and it turned out it was the starter. Put a new starter on and it starts every time now.

[AngryPirate]

Originally Posted by dmacs66gmc

Mine was doing the same thing as yours and it turned out it was the starter. Put a new starter on and it starts every time now.

Noted. I guess I could see if I could get a newer, better starter.

Thanks!

[AngryPirate]

Originally Posted by slorio

Pirate:
A few things to check:
* Ignition timing to make sure it is on spec.
* Choke to make sure it is closing all the way.
* Accelerator pump. Take off air cleaner and open throttle while you look down carb with a flashlight. Make sure you have a nice pump shot of gas in the carb throat after it has sat overnight. If not, then you are cranking to get gas back to fill the carb bowl before you have a chance to start. Bad accelerator pump or gas leaking into engine from float bowl could be causes.

These V6's seem to like to be rich to fire up after they have sat for a while. I close choke all the way pump accelerator pump a couple of times and crank a bit. If it doesn't light off, I stop, pump accelerator again a couple of times and repeat. If it has sat for a week, it takes a few round of this to light off.

Hope this helps.
Regards,
Steve
New Orleans

You raise some good points here. I believe it is trying to pump gas back into the carb from the get go. The leaking accelerator pump/float bowl seems like a reasonable place to start. The timing is relatively close, but I should throw a light on it again to double check.

Thanks for the reply!

[Brad54]

Is it not turning over (or turning over very slowly and weakly), or is it turning over and not "catching" or firing/starting?
If it's not turning over/slow weak turn, you've got an electrical problem that isn't "the engine." It's wiring, ballast resistor, etc., or the starter itself.

If it's turning over and not firing, it's timing or fuel system. Fuel system will be the pump, the filter or the carb. Timing is distributor, points--which includes having the distributor dropped in the hole a tooth off, or having the plug wires on the wrong posts on the cap.

While not "factory correct" for most applications, I like to put an inline fuel filter between the pump and the carb specifically to diagnose these kinds of problems down the road. A reproduction glass-bowl filter from early '60s chevys always looked "right" on our trucks.

I've had bad fuel pumps behave like you're describing, and timing issues behave that way, too.

One thing to keep in mind when chasing an issue like this: An engine needs fuel, timing, compression and spark to run. If it has those things, it can't help but run--it has no choice.
If it isn't running, it's one of those things. (and before that comment goes sideways, we'll consider "air" to be a component of "fuel")
That sounds simplistic but sometimes being reminded of the basics clears the cobwebs of our minds.

-Brad

[AngryPirate]

Originally Posted by Brad54

Is it not turning over (or turning over very slowly and weakly), or is it turning over and not "catching" or firing/starting?
If it's not turning over/slow weak turn, you've got an electrical problem that isn't "the engine." It's wiring, ballast resistor, etc., or the starter itself.

If it's turning over and not firing, it's timing or fuel system. Fuel system will be the pump, the filter or the carb. Timing is distributor, points--which includes having the distributor dropped in the hole a tooth off, or having the plug wires on the wrong posts on the cap.

While not "factory correct" for most applications, I like to put an inline fuel filter between the pump and the carb specifically to diagnose these kinds of problems down the road. A reproduction glass-bowl filter from early '60s chevys always looked "right" on our trucks.

I've had bad fuel pumps behave like you're describing, and timing issues behave that way, too.

One thing to keep in mind when chasing an issue like this: An engine needs fuel, timing, compression and spark to run. If it has those things, it can't help but run--it has no choice.
If it isn't running, it's one of those things. (and before that comment goes sideways, we'll consider "air" to be a component of "fuel")
That sounds simplistic but sometimes being reminded of the basics clears the cobwebs of our minds.

-Brad

It is turning over, but yes, weak. It doesn't really even seem like there is fuel or much spark going on until I add another vehicle into the mix to help crank the starter. The ballast resistor on the coil is new as is the coil.

The battery is at full charge and it still takes a boost to even coax it into wanting to really start. Once it's started, it seems to be happy enough.

I may put one of those AC glass filters inline. My truck already has an AC delco element canister under the passenger side, bolted to the frame rail (new element), my concern is having 2 filters in line might cause more resistance for the fuel to get to the carb?

If it could have a strong turn over of the engine for 5 seconds, I think all of the fuel necessary to start would be there..but I get like 2 or 3 seconds of marginal turn over.

Perhaps I can get another new starter or at least take the old one out and have it tested.

I'll go over all of the components again, just to be sure.

Thanks for the advice, Brad.

[TJ's Chevy]

Pirate, I'm sending an email.

[MikeN]

Check the condition of your battery cables, the terminals on the cables, and all your grounds.

[AngryPirate]

Originally Posted by MikeN

Check the condition of your battery cables, the terminals on the cables, and all your grounds.

All new 4 GA battery cables and I believe I cleaned off a good spot for the ground, but worth double checking as well.

Thanks!

[Brad54]

I wonder if the battery isn't getting a full charge--meaning, the charging system, while rebuilt or replaced, isn't doing its job.
I had the generator rebuilt in my '54 Buick a few years ago... their "rebuild" was new brushes and a fresh can of spray paint.
I found a REAL rebuilt generator, and that problem was fixed.
I also had problems with two Pertronix units: the one in the Buick (broken wire), and the one in our '61 Corvair (never diagnosed what the actual problem is, but if anybody would like to study it yourselves, the unit is somewhere in the woods behind my shop).
But that affects the engine firing, not the battery charging. Same with the coil.
Generator/Alternator affects battery charge.

You know... now that I think about it, it COULD be the ignition switch, too... It might be worn, and no longer making a good contact when you turn the key. It's original, and 50 years old. How are the wires under the dash? Cracked, broken, 50 years of Bubba Wiring, etc. can cause a problem too.

See how much juice is going to the starter terminal when the key is turned.

-Brad

[AngryPirate]

Originally Posted by Brad54

I wonder if the battery isn't getting a full charge--meaning, the charging system, while rebuilt or replaced, isn't doing its job.
I had the generator rebuilt in my '54 Buick a few years ago... their "rebuild" was new brushes and a fresh can of spray paint.
I found a REAL rebuilt generator, and that problem was fixed.
I also had problems with two Pertronix units: the one in the Buick (broken wire), and the one in our '61 Corvair (never diagnosed what the actual problem is, but if anybody would like to study it yourselves, the unit is somewhere in the woods behind my shop).
But that affects the engine firing, not the battery charging. Same with the coil.
Generator/Alternator affects battery charge.

You know... now that I think about it, it COULD be the ignition switch, too... It might be worn, and no longer making a good contact when you turn the key. It's original, and 50 years old. How are the wires under the dash? Cracked, broken, 50 years of Bubba Wiring, etc. can cause a problem too.

See how much juice is going to the starter terminal when the key is turned.

-Brad

"if anybody would like to study it yourselves, the unit is somewhere in the woods behind my shop)." - this made me laugh.

Bubba didn't actually do much to the truck. It was pretty much bone stock and no real splicing done. The ignition switch is vintage, but not original to this truck.

The generator I believe was rebuilt properly as they replaced a bunch of the insides and made a point to tell me I no longer needed to use those oil ports as they had replaced them with newer style bearings. When running and not attached to the battery the generator it putting out ~14v . Amps, I'm unsure. Worth another look or take it to be retested.

All good information, I'll go over everything again.

Thanks!

[jtrichard]

IS the HOT start still hooked up? After looking at your first post again I see you do not have points any longer I dont know if the HOT start works with the set up you have someone else might know

[AngryPirate]

Originally Posted by jtrichard

IS the HOT start still hooked up? After looking at your first post again I see you do not have points any longer I dont know if the HOT start works with the set up you have someone else might know

I don't even know what a hot start is.

[WorkinLonghorn]

You're saying it cranks slowly? Then how many things could it be? A bad battery, bad connections, bad starter, internal friction.
Personally, I would take that battery back and have them test it. Even AutoZone has this equipment. If it checks out (you could even mount it to another big engine to see how it performs) then I would take the time to check your cables and your ground connections carefully. Then if no joy I would take that starter back and have it bench tested or just replaced. If you bought it at autozone or a similar place, consider going to a place that services the repair shops in the area and pay a little more maybe for a good strong starter. Internal friction from water in some cylinder/s or whatever would be pretty obvious.

[AngryPirate]

Originally Posted by WorkinLonghorn

You're saying it cranks slowly? Then how many things could it be? A bad battery, bad connections, bad starter, internal friction.
Personally, I would take that battery back and have them test it. Even AutoZone has this equipment. If it checks out (you could even mount it to another big engine to see how it performs) then I would take the time to check your cables and your ground connections carefully. Then if no joy I would take that starter back and have it bench tested or just replaced. If you bought it at autozone or a similar place, consider going to a place that services the repair shops in the area and pay a little more maybe for a good strong starter. Internal friction from water in some cylinder/s or whatever would be pretty obvious.

I agree with your sentiment. Which is why I'm stuck, since most everything has been replaced with new or rebuilt.

I believe I have done some due diligence here...I'm just looking for suggestions I may have missed or known issues with this particular truck with these specs.

I am loaded with a bunch of good ideas thanks to these responses.

Thank you as well for your insight.

[jtrichard]

With stock wiring,points and coil there is a resistor wire built into the harness that drops the voltage to the coil (when running) ....When cranking there is a bypass to that resistor wire that throws FULL voltage to the coil that about doubles the spark so it starts MUCH easier....It hooks to the "R" terminal on the starter solenoid

[Brad54]

One last tip: Never trust new parts to work. Especially these days with off-shore parts.
Just because the starter is new, doesn't mean it works right.
I've seen this time and again.

Incidentally, this is also the case with NOS parts--a lot of parts at the dealership didn't work, so they went back in the box, back on the shelf and another one was pulled and installed. I've seen NOS parts not work a bunch of times too.

-Brad