Carb Stalling Troubleshooting...Flooded ?

[ck80]

No oil was squirted into the cylinders when I did a compression test, to see if things improved.

That's just one method to help tell if rings are an issue, only reason I asked. Often more than one test can help tell the same things, just more data to figure out where things are.

No, never smelled gas in the oil when I did an oil change.

Would be a symptom of the gas washing the rings, but, nothing to say something didn't happen before you owned it.

Do I need a leak down tester gauge kit or just a mechanics stethoscope to perform this leak down test ?View attachment 184957View attachment 184958

Well, the gauge kit shows you how much pressure is lost. Idea is you turn over engine with breaker bar by hand until the piston is at top of stroke, then put the gauge into spark plug hole, pump it up with compressed air, and two things happen - 1) you see how much air is lost, like a traditional compression test, while 2) listening to hear where the air is escaping to. Depending where you hear air going you know if it is a ring issue, valve issue, headgasket issue, etc.

So to really get the full benefit of the leakdown test is best to scope it

 

[olskool]

i am new here, i am a freshly retired professional transmission rebuilder of 45 years. i have not read the whole thread, but from your first post it sounds like i problem i had in around 1980 my girlfriend, wife now since 81, had a 1974 GTO it did the same thing. it would run perfect for about 2 miles then start bucking and shut off. then crank up and run for another miles. i did everything to fix it! nothing helped. then i pulled the gas tank. it had a hand full of water in the tank. dumped it, and bam! fixed. then latter i was working in a shop, a truck came in doing the same thing, i knew exactly what it was,,,,,,,,,,,,,,,,

 

[Tynan918]

i am new here, i am a freshly retired professional transmission rebuilder of 45 years. i have not read the whole thread, but from your first post it sounds like i problem i had in around 1980 my girlfriend, wife now since 81, had a 1974 GTO it did the same thing. it would run perfect for about 2 miles then start bucking and shut off. then crank up and run for another miles. i did everything to fix it! nothing helped. then i pulled the gas tank. it had a hand full of water in the tank. dumped it, and bam! fixed. then latter i was working in a shop, a truck came in doing the same thing, i knew exactly what it was,,,,,,,,,,,,,,,,

Hmmmmmm water in the gas tank ? I have found little black specks floating around the clear plastic filter before... Never understood why there would be black specks unless the gas was old or the tank was dirty.

 

[Tynan918]

Starting to think the $8,000 I paid for the car was overpriced... None of these problems where listed and I was told the engine was a rebuilt 350 with 46,000 miles and a 200r4 4 speed transmission... I have a 305 and a TH350 3 speed transmission.

 

[Tynan918]

That's just one method to help tell if rings are an issue, only reason I asked. Often more than one test can help tell the same things, just more data to figure out where things are.

Would be a symptom of the gas washing the rings, but, nothing to say something didn't happen before you owned it.

Well, the gauge kit shows you how much pressure is lost. Idea is you turn over engine with breaker bar by hand until the piston is at top of stroke, then put the gauge into spark plug hole, pump it up with compressed air, and two things happen - 1) you see how much air is lost, like a traditional compression test, while 2) listening to hear where the air is escaping to. Depending where you hear air going you know if it is a ring issue, valve issue, headgasket issue, etc.

So to really get the full benefit of the leakdown test is best to scope it

So would I need the double gauges and the stethoscope ? Or just the stethoscope alone ?

 

[DRIVEN]

I would say you overpaid, but that's all behind you now.

On the timing: I've found that a lot of SBCs like around 8-10* innitial and 32-35* total advance. Every engine is different but that seems to be the ballpark. If it doesn't bump up against the starter during cranking and doesn't ping, you're probably fine. After timing is set, you'll probably find that the carb needs readjusted.

On the compression test: Those numbers aren't good. You've got a mystery motor that's 35-45 years old and has unknown miles. Based on what I've seen in the photos of the car's overall state, it probably wasn't pampered. If it were mine, I'd just get it running as best as possible and understand it'll never really run right. You can't tune out a mechanical deficiency but you can still enjoy the car in the meantime.
Time to start thinking about a replacement. Rather than buy someone else's 40 year old mystery motor, I'd seriously consider a GM or similar crate engine with a warranty. If you decide to buy someone else's mystery motor, please at least buy something that you can hear run first and get a compression test before handing over the cash.

 

[Tynan918]

I would say you overpaid, but that's all behind you now.

On the timing: I've found that a lot of SBCs like around 8-10* innitial and 32-35* total advance. Every engine is different but that seems to be the ballpark. If it doesn't bump up against the starter during cranking and doesn't ping, you're probably fine. After timing is set, you'll probably find that the carb needs readjusted.

On the compression test: Those numbers aren't good. You've got a mystery motor that's 35-45 years old and has unknown miles. Based on what I've seen in the photos of the car's overall state, it probably wasn't pampered. If it were mine, I'd just get it running as best as possible and understand it'll never really run right. You can't tune out a mechanical deficiency but you can still enjoy the car in the meantime.
Time to start thinking about a replacement. Rather than buy someone else's 40 year old mystery motor, I'd seriously consider a GM or similar crate engine with a warranty. If you decide to buy someone else's mystery motor, please at least buy something that you can hear run first and get a compression test before handing over the cash

Most definitely... I'm preparing for it.

But I want to do the full test on this engine right now and see where I stand on that.

 

[Tynan918]

I can't afford a leak down tester gauge, unless I order one online and wait a week for shipping... 🤔🤔🤔🤔... Trying to contact everyone I know I could think to have one...

 

[Tynan918]

On the timing: I've found that a lot of SBCs like around 8-10* innitial and 32-35* total advance.

Yea I've read that too... But the emissions sticker says 6° @ 600 rpm...

When I had to set the timing the first time, I had it set at 8° BTDC on compression stroke by rotating the engine by hand, pointed the rotor to cylinder 1, and bumped the starter as instructed in this video...

But I didn't have a timing light and it didn't run correctly, and I was told I did it wrong, and not to bump the starter but to use a long screw driver to turn the oil pump shaft to
mate with the distributor with the pointer at cylinder 1 and sitting flush on the intake manifold... I did that and attempted to drop the idle down to 600 rpm and set timing at 6° BTDC but couldn't without the car stalling, so I did it with the lowest rpm I could with the engine running smoothly, about 800-900 rpm... again, no test light...

But now that I have a clearer understanding of the timing light, I want to set the timing correctly once and for all...

Quick question though...the degrees on the timing light dial, what do those numbers represent ?

Is this "total timing" and is it telling me my total timing is over 60° ??

 

[Tynan918]

That's just one method to help tell if rings are an issue, only reason I asked. Often more than one test can help tell the same things

With that being said, would I need a leak down gauge ?

I only have $40 to work with at the moment, and in store prices are $70 and up on the leak down gauges in my area.