Diagnosis, please

[47heaven]

Have another problem I need you Mopar techs to diagnos for me.

Problem:

Lately, for some reason, after I stop and park the P15 for a while, whether it be to go eat or go to the store, I notice that when I get back in to start it, I can smell gas and the engine will turn over, but won't get any ignition unless I pump the pedal a couple times (sort of how it would act if it were flooded). It then sputters from a slow sputtering to faster sputtering until the engine runs normally. I even get a couple backfires right after when I rev it. I checked to see if gas is leaking out of the carb, but don't see any trace of any wet gas, like with the older carb. Again, it won't do this when I first start the car up, but after driving for a while, it will happen, and more commonly than before.

Any ideas?

[BobT-47P15]

Is your choke opening all the way???

[47heaven]

Is your choke opening all the way???

You know...that might be it because I notice that it was sticking a while back. Didn't even give it a thought. I'll check it out tomorrow when there is light. Thanks, Bob!

[Plymouthy Adams]

I would suspect that the carb float level is a tad high..when sitting after a run the block transfers heat to the harb and causes perculation..this act is the expansionof the fuel in teh bowl tillit spills over in the throat of the carb..causes flooding (smell of fuel) and the rich mixtures will cause erratic running and hard start and black soot at the tailpipe when it does fire..the pumping of the [pedall..should be ano no but to hold the pedal to the floor shuts all all fuel and allows air in to mix with the fuel and clears the flooded condition...next time you park..take the breather top off..if after a few minutes you start to see a vapor collection in the throat of the carb..this is you perculation sign..

[47heaven]

I would suspect that the carb float level is a tad high..when sitting after a run the block transfers heat to the harb and causes perculation..this act is the expansionof the fuel in teh bowl tillit spills over in the throat of the carb..causes flooding (smell of fuel) and the rich mixtures will cause erratic running and hard start and black soot at the tailpipe when it does fire..the pumping of the [pedall..should be ano no but to hold the pedal to the floor shuts all all fuel and allows air in to mix with the fuel and clears the flooded condition...next time you park..take the breather top off..if after a few minutes you start to see a vapor collection in the throat of the carb..this is you perculation sign..

Thanks Tim. It's over 100 today, so I'll wait until it cools down to try that test.

[Young Ed]

Darin when its really hot out is when it does that. If you wait til it cools down the problem will probably go away until the next time its hot out. You should brave the heat and check it out.

[De Soto Frank]

Darin,

What carb are you running on your P-15 ?

Somewhere on another post, Greg G quoted "starting a warm engine" instructions from his P-15 owners' manual: it stressed "depressing the accelerator pedal halfway to the floor and holding it there while operating the starter" - this helps clear-out any gasoline that has percolated into the intake manifold.

Again, let us know what carb is on your car.

De Soto Frank

[47heaven]

Darin,

What carb are you running on your P-15 ?

Somewhere on another post, Greg G quoted "starting a warm engine" instructions from his P-15 owners' manual: it stressed "depressing the accelerator pedal halfway to the floor and holding it there while operating the starter" - this helps clear-out any gasoline that has percolated into the intake manifold.

Again, let us know what carb is on your car.

De Soto Frank

Frank...I don't have the model number of the carb, but's the one that goes on a 1949 Dodge 230 engine w/auto choke (though the auto choke is disconnected). It is a Carter, believe

[Rodney Bullock]

I think Tim has your problem isolated. If you smell gas that means you got more than you need. The float level is very important, that 100 degree weather don't help either:rolleyes: I bet if you had a different carb it would not hurt. than again I have a Plymouth 217 so maybe that's what came on a dodge.

[greg g]

Assure the choke is fully opened when the engine is hot , set the float about 1/32 to 1/16 lower than factory spec. Follow the hot start procedure as oted above or hold wide open while cranking. Pumping the pedal only adds more raw gas to that which is already sitting in the manifold.

[Normspeed]

I battle with this same problem in the hot weather. It's a pain. Only happens on a hot day, when you shut off the motor hot. Talking 100 degree weather. After 15-30 minutes, try to restart, smell raw gas, it cranks several seconds, then fires up, sputters a few seconds before it clears the excess gas, then runs ok. My floats are set way low, it still does it though. I avoid it by switching off my electric fuel pump when I enter the parking lot, so while I'm getting parked the motor is using up some of the gas in the float bowls. When I restart, I switch on the electric and let it refill the carb bowls and it fires right up.

Darin, if you solve this one I'd sure like to hear how you did it:D

BTW, Darin is running a very nice looking rebuilt Ball & Ball, the type with the dashpot screw on the float bowl.

[Rodney Bullock]

That hot start procedure makes alot of sense, I have used it many times, pushing the pedal all the way down to the floor is the way to go when everything is hot. I have not had those problems since my invention:D you all know what that is:cool:

[47heaven]

I was talking to my uncle on the internet the other day and he told me this, "You are suffering from bleed down in your carburator. The needle and seat are not shuting off the fuel in the bowl and there is too much fuel pressure. Sounds like something wrong in the fuel system and that is exactly what is happening to make your engine flood. Probably the fuel pump puts more pressure that it needs."

So, it sound like exactly like what you guys are telling me. Should I just go to the electric pump instead? The carb I have is a good one, Norm (normspeed) can atest to that.

[greg g]

Don't see how a new pump with more flow and more pressure is gonna solve the flooding problem. Check your needle and seat and lower the float level. See if that helps, and aside from time its free.

You could also fashion a sheetmetal heat shield to mount under the carb to reflect some of the maifold head away from the float bowl.

[Plymouthy Adams]

question...have you verified spill over...and then is the spill over due to heat or due to the needle and seat...both could be a source for your problem but UNTIL you do the look see and rule one out over the other..you are still just guessing and guessing does not always get you there....make a SWAG and not a WAG

[Don Coatney]

Have another problem I need you Mopar techs to diagnos for me.

Problem:

Lately, for some reason, after I stop and park the P15 for a while, whether it be to go eat or go to the store, ?

I think most here are avoiding the obvious. What are you eating or what are you buying in the store? These questions are important to remedy your problem and the problem is time based.

[Normspeed]

Don, once again you have seen clearly through the fumes and uncovered the most likely source. The raw gas could very well be burrito-based.

My hat is off to you.

[47heaven]

I think most here are avoiding the obvious. What are you eating or what are you buying in the store? These questions are important to remedy your problem and the problem is time based.

Ha Ha...sorry, but I don't release that gas in my car. I simply pull over, get out and walk around until I'm out of gas. So I guess that rules out the obvious.

[47heaven]

question...have you verified spill over...and then is the spill over due to heat or due to the needle and seat...both could be a source for your problem but UNTIL you do the look see and rule one out over the other..you are still just guessing and guessing does not always get you there....make a SWAG and not a WAG

I think I already mentioned that I don't see a spill over or any wet gas outside the carb. So it must be puddling inside.

[Plymouthy Adams]

it does not spill over outside the carb..it will spill over to the the inside of the carb..that is why I said you have to look inside the throat of the carb to see if the vapors are forming...please re-read my first answer to you...maybe you will see just what I was telling you to begin with..see article below..this will explain the problem..but you don't need this for for the fix...you need to set your float level to the proper height..

http://www.theclassiccougarnetwork.com/tccn2/tech/quicktips/quick30/quick30.html

[47heaven]

it does not spill over outside the carb..it will spill over to the the inside of the carb..that is why I said you have to look inside the throat of the carb to see if the vapors are forming...please re-read my first answer to you...maybe you will see just what I was telling you to begin with..see article below..this will explain the problem..but you don't need this for for the fix...you need to set your float level to the proper height..

http://www.theclassiccougarnetwork.com/tccn2/tech/quicktips/quick30/quick30.html

Tim...I got what you said, but I haven't been able to test it yet. Does Edelbrock make that gasket for our kind of carbs or would it matter since mine isn't aluminum?

[Plymouthy Adams]

Darrin..agian I repeat..first thing to do is to set the float level..seeing as how everyone else does not have a spacer your car will not require one either. You have no need for gimmicks or voodoo parts. You can set the float level a bit lower than factory and still work effectively..the level of fuel in the bowl is to assure that you will have enough fuel for rapid acceleration so you will not run out of fuel getting to speed. I am quite sure your engine is not running so rich that that scenario will occur especially if you have a working fuel pump as the fuel is being replaced as you accelerate anyway. In 1975/76 I think about every 1 barrel carb ever put on a Ford product had to have the float level lowered due to the same thing you are experiencing but sorta amplified cause by internal design, a hard turn in either direction would cause the fuel to splash over and oft times kill the engine..always caused sputtering, not your safest operational enviroment. Before spending any money or taking it to a shop to pay for what they may guess is the problem..try this first...

[old woolie]

Lowering the float fixed that problem for me.

[Don Coatney]

Don, once again you have seen clearly through the fumes and uncovered the most likely source. The raw gas could very well be burrito-based.

My hat is off to you.

Ha Ha...sorry, but I don't release that gas in my car. I simply pull over, get out and walk around until I'm out of gas. So I guess that rules out the obvious.

You both missed the point. Not that I believe vapor lock is a real problem but read on.....

A complaint was received by the Pontiac Division of General Motors: 'This is the second time I have written to you, and I don't blame you for not answering me, because I sounded crazy, but it is a fact that we have a tradition in our family of Ice-Cream for dessert after dinner each night, but the kind of ice cream varies so, every night, after we've eaten, the whole family votes on which kind of ice cream we should have and I drive down to the store to get it. It's also a fact that I recently purchased a new Pontiac and since then my trips to the store have created a problem.....

You see, every time I buy a vanilla ice-cream, when I start back from the store my car won't start. If I get any other kind of ice cream, the car starts just fine. I want you to know I'm serious about this question, no matter how silly it sounds "What is there about a Pontiac that makes it not start when I get vanilla ice cream, and easy to start whenever I get any other kind?"

The Pontiac President was understandably skeptical about the letter, but sent an Engineer to check it out anyway. The latter was surprised to be greeted by a successful, obviously well educated man in a fine neighborhood. He had arranged to meet the man just after dinner time, so the two hopped into the car and drove to the ice cream store. It was vanilla ice cream that night and, sure enough, after they came back to the car, it wouldn't start. The Engineer returned for three more nights. The first night, they got chocolate. The car started. The second night, he got strawberry. The car started. The third night he ordered vanilla. The car failed to start.

Now the engineer, being a logical man, refused to believe that this man's car was allergic to vanilla ice cream. He arranged, therefore, to continue his visits for as long as it took to solve the problem. And toward this end he began to take notes: He jotted down all sorts of data: time of day, type of gas uses, time to drive back and forth etc.

In a short time, he had a clue: the man took less time to buy vanilla than any other flavor. Why? The answer was in the layout of the store. Vanilla, being the most popular flavor, was in a separate case at the front of the store for quick pickup. All the other flavors were kept in the back of the store at a different counter where it took considerably longer to check out the flavor.

Now, the question for the Engineer was why the car wouldn't start when it took less time. Eureka - Time was now the problem - not the vanilla ice cream!!!! The engineer quickly came up with the answer: "vapor lock". It was happening every night; but the extra time taken to get the other flavors allowed the engine to cool down sufficiently to start. When the man got vanilla, the engine was still too hot for the vapor lock to dissipate.

[Normspeed]

Jeez Don, I don't know...that's really a stretch...but you being a zen master and all...

I'll stick with the burrito theory.