Malibu Drive

[HanksB3B]

Yesterday I decided to do something different, drive to Malibu. After driving the truck at 45-50 mph on a long stretch (about 20 miles) I pulled in to Neptune’s for lunch before heading up to the Circle” X” Ranch rangers station about 2,500 ft above sea level. I parked on a slight upgrade, maybe 5deg and turned the engine off. Neptune’s is a pretty cool biker hangout that has really good clam chowder, seafood and just about everything else. Because it’s Malibu you never know who’s going to show up on some exotic bike. Well one thing for sure about our trucks is that I always get thumbs up from bikers.

After a 20 minute break, I finish my clam chowder and am ready to hit the road. It won’t start. I pull the throttle all the way out, not even an encouraging almost. Well you know how it goes each attempt wears the battery down a little and you start thinking stuff like “If AAA jumps it with 12V, will it do any harm”. Maybe I’ll call Ricardo, o.k., Ricardo tells me to let it cool down, so I do. The temperature gauge takes forever to move below 160. Mike keeps me company for about a half hour or more. pouring something from somewhere into his lemon Sobe and telling me jokes like “What do you call a guy with a wooden leg..Hop a long..and his one-legged girlfriend..Ilene” and some other stories about growing up in the 60’s in California.

Finally the truck starts and I debate about licking my wounds and just heading home. No, before the no-start, she didn’t miss a beat and I decide to head up as intended to Circle “X”. The roads are narrow, but not so much as two heads-up drivers can’t pass in the opposite direction. I decide to keep the truck running even for the photos I take a long the way. She doesn’t miss a beat all the way home and I’m relieved as I pull into the parking place. Thought I’d share a great run and a beautiful day with you.

Thoughts and Questions:

Would it have been a better idea to park on the flat not on a slight uphill grade and let the truck run at idle for a few minutes rather that shut down quickly from 45-50mph.

Would a 12 Volt jump damage anything?

Would a shot of Ether fired her right up?, and is there any danger to the engine in doing so.

Is it considered safe to carry a can of Starter Fluid?

Thanks,

Hank

[jakenoklahoma]

If I had to guess, I am thinking vapor lock...IMHO

[HanksB3B]

It is in the fuel line itself correct? I have a rubber fuel line. My mechanic friend Pat swears by a steel line as away from the block as possible with wodden clothspins clipped to it.

Hank

[TodFitch]

Maybe your carburetor float level is set high and when you parked the heat soaking caused the fuel to expand a bit then flood the manifold.

Nice set of pictures. I used to live just off Mulholland Hwy in Calabasas so we did a lot of driving in the Santa Monica mountains.

[HanksB3B]

Maybe your carburetor float level is set high and when you parked the heat soaking caused the fuel to expand a bit then flood the manifold.

Nice set of pictures. I used to live just off Mulholland Hwy in Calabasas so we did a lot of driving in the Santa Monica mountains.

I guess I need to check my float level. It's an easy job right you just have to take off the air horn and use a gauge from the carb kit to measure right?

Thanks,

Hank

[austinsailor]

I'd strongly suspect vaperlock. On my 48 I just resurectedi'm having a big problem with it. I think today's fuel is contributing to it.

In you case, the higher elevation would make you more likely to experience it.

Mine runs just great, but if I stop for much longer than a stoplight after running at highway speed more than 2 miles or so, I'm toast. Since I still have a outboard tank and primer bulb I can just give it a few squeezes and I'm off again. Pouring gas in the carb or using starter fluid would fire it up but I do not know if it would overcome the vapor and start pumping fuel or not.

I'm going to try several things. I bought a quart of lead additine at a vette meet last week, it's supposed to raile the boiling point of fuel something like 50 degrees. Should help a lot, but it's a contuing expense. I'll also try av gas. If eiter or both solve it, I should be confident vapor lock is really the problem.

Next step is to insulate the fuel line real well to try to stop it. Should be better than clothes pins, although not quite the conversation piece.

I know insulting the fuel line isn't period correct, but they didn't have to deal with this crap-for-fuel we have today.

[TodFitch]

I'd strongly suspect vaperlock. On my 48 I just resurectedi'm having a big problem with it. I think today's fuel is contributing to it.

In you case, the higher elevation would make you more likely to experience it.

Mine runs just great, but if I stop for much longer than a stoplight after running at highway speed more than 2 miles or so, I'm toast. Since I still have a outboard tank and primer bulb I can just give it a few squeezes and I'm off again. Pouring gas in the carb or using starter fluid would fire it up but I do not know if it would overcome the vapor and start pumping fuel or not.

I'm going to try several things. I bought a quart of lead additine at a vette meet last week, it's supposed to raile the boiling point of fuel something like 50 degrees. Should help a lot, but it's a contuing expense. I'll also try av gas. If eiter or both solve it, I should be confident vapor lock is really the problem.

Next step is to insulate the fuel line real well to try to stop it. Should be better than clothes pins, although not quite the conversation piece.

I know insulting the fuel line isn't period correct, but they didn't have to deal with this crap-for-fuel we have today.

2500 feet elevation (about the highest point in the Santa Monica Mountains) should not be enough altitude to make any difference. The climb up there and ambient temperature probably do make a difference.

Am I assuming correctly that both of you have the fuel pump heat shields installed?

(The only time that I ever had issues with vapor lock was 30 years ago when I had a burnt exhaust valve and the manifold above the fuel pump got very hot. But my car is different in a number of ways from your later vehicles. No water distribution tube, no vacuum advance, no fuel pump heat shield, lots of hood louvers to promote air flow in the engine compartment.)

[Don Coatney]

I used to live just off Mulholland Hwy in Calabasas

A couple of weeks ago I watched the movie "MULLHOLLAND FALLS". Great movie as there are lots of old cars.

I'd strongly suspect vaperlock.

Exactly what is vapor lock? If you are suggesting that vaporized fuel between the fuel pump and carburetor is vapor lock I believe that is physically impossible. The fuel pump will push air out of the line and fuel to the carburetor. However the fuel pump will not pump fuel if there is an air leak in the line from the fuel tank to the fuel pump. But if that were the case the engine would run out of fuel and stop while driving. I suspect the problem here is heat expansion of the gas in the carburetor bowl flooding the manifold as has been suggested.

[jakenoklahoma]

VAPOR LOCK http://autorepair.about.com/cs/generalinfo/l/bldef_856.htm

Definition: When gasoline overheats and boils inside the carburetor bowl or fuel pump of a hot engine, it ceases to flow. This can cause stalling or hard starting. This is called vapor lock, and it usually happens during hot weather. If a hot engine won't start, all you can do is let it sit and cool off. You should check the cooling system to see if anything is causing the engine to run unusually hot (a bad thermostat or cooling fan, for example). Switching brands of gasoline may also help.

[HanksB3B]

I was at sea level when I couldn't re-start. I have noticed a little excess gas dripping from the carb ocasionally, so I do think float level has something to do with it. I'm also thinking Vapor Lock has something to do with it. The truck was parked at an odd angle and I think this also has something to do with it.

Will investigate and try to come up up something. Ideas gratefully accepted.

Thanks,

Hank

[Don Coatney]

Please follow this link and read all the threads. Vapor lock is not possible in a vented pressurised system such as we have in our old mopars.

http://www430.pair.com/p15d24/mopar_forum/search.php?searchid=642865

[Merle Coggins]

I have to side with Don on this. I believe "vapor lock" is a mythical ailment used to explain an unknown hot starting problem. I used to have a problem with my truck starting hard when hot. I found that if I gave it just a little bit of throttle it would start up better. Not full throttle but just enough to open the throttle plate. It got even worse when my points gap was too small, which makes for weak spark. This also made the timing wrong which didn't help. After readjusting the points and timng and lowering the float level a little bit the problem is nearly gone. It'll still start different when sitting hot for 5 - 15 minutes. It'll crank just a few revolutions longer and seems to always start right when I let my foot off the starter and tap the gas. One of these days I'm going to replace my coil since it is still the one that was on the truck when I got it. I have no idea how old it is, but it still works. Maybe that'll help too.

Bottom line... drop the float level slightly and recheck your tune up. For a test take it for a spin and park it back in your driveway. Go out after 10-15 minutes and see how it starts. If it fails the test at least you're not stranded far from home.

Merle

[NiftyFifty]

Is it possible your advanced a bit too much on your timing and when she's hot it's just a bit too much? Typically when this is the case it cranks a lot slower, but maybe you found the sweet spot inbetween?

Just one more thought, that and converting it to 12V so you don't wear the battery down after 2 cranks

[austinsailor]

Can anyone explain why, when I'm experiencing what I believe is vapor lock, I can pump about 6 squeezes of the outboard bulb before getting resistance?

Where would this fuel be going?

It starts just like normal as soon as it's pumped to get resistance.

[Don Coatney]

Can anyone explain why, when I'm experiencing what I believe is vapor lock, I can pump about 6 squeezes of the outboard bulb before getting resistance?

Where would this fuel be going?

It starts just like normal as soon as it's pumped to get resistance.

I do not understand outboard bulb ? What is it?

[TodFitch]

Just one more thought, that and converting it to 12V so you don't wear the battery down after 2 cranks

And just what does 12v do in that regard different than a 6v system that is in good condition? My carburetor leaks out enough that if the car sits for a week or more I need to crank it quite a long time. The 6v starter and battery are quite happy to do that. And it does take more than "2 cranks".

[48Dodger]

Vapor lock occurs between the gas tank and the fuel pump. The fuel goes from a liquid state to a gas state reducing the output of the pump. Its tough to clear the line after you stop...unless you let things cool down. When you say you have a rubber fuel line, are talking about from the tank to fuel pump, or pump to carb? In racing, vapor lock is a big deal. The fuel pump gets the fuel line hot (cuz its connected to the block) dropping the fuel bowl level and affecting the performance of the carb. In most cases the fuel is traveling uphill, which gives vapor lock a chance to occur in the right stituation.

48D

Edited May 22, 2010 by 48dodger

[Allen I.]

I do not understand outboard bulb ? What is it?

For some of us unable to find a gas tank, we use a tank designed for a boat. The fuel line has a primer bulb to get the gas started from tank to carb.

It makes starting a lot easier for me but does not look so nice sitting in the back of the truck. I need to disguise mine with an old shipping crate or something.

As for the 12v jump start, I'd avoid as much as possible and connect right to the starter. I have had to do this and boy does that starter spin.

Next upgrade for me is to get the correct gauge battery wires for the 6v system. The PO has 4 gauge installed and the system does not like so extra special much.

[Don Coatney]

For some of us unable to find a gas tank, we use a tank designed for a boat. The fuel line has a primer bulb to get the gas started from tank to carb.

Now I get it. Having never owned a boat in my life I did not understand.

[austinsailor]

Interesting question about the rubber vs metal line. I did have a metal stub on the fuel pump, about 6" long, and a rubber line from there drooping down on the right side, then through a hole in the rusty floorboard to an outboard tank sitting on the right floorboard. I don't recall having a vapor lock (or whatever problem it really is) while it was set up that way. I was a bit concerned having that gas right there in the cab with me, and I was making a new tank, so I ran a steel line exactly as the original one was, and it went back to the bed/cab joint and turned up. I then put the rubber line on that with the tank in the bed. Then the problem started.

I have a new aluminum tank nearly finished, but I'm reluctant to install it. If I have a vapor lock problem with it, I won't have the bulb to push new gas through. I'd have to wait for the cool down.

But, thinking this through, maybe what I need to do is put a rubber line over the steel line to insulate it. I would guess that would solve the whole problem. I'll report back when I get that done.

And I feel sorry for Don - never had a boat? I have about 15, need one? In fact, I'm typing this sitting on my sailboat in Texas this morning.

[jakenoklahoma]

Electric pumps alleviate this problem, which is one reason you seldom see anything like vapor lock on modern cars, that and the constant fuel pressure in the line required for a fuel injected engine. block mounted pumps are excellent heat sinks and the positioning of fuel pump so close to the exhaust manifold contribute to this phenomena. other factors like float level, timing and low battery or bad grounds can contribute to starting problems, but vapor lock is a real thing. it is a characteristic of fluid hydraulics.

[MBF]

If you're carb is leaking from the float being set too high-this is a problem I've experienced in the past too. What this does is drip excess gas liquid down in the manifold that is not properly atomized for combustion. Cranking a hot motor takes more energy so the starter may be using more than the nomal amp draw to crank the engine. This can reduce the amount of power going to the coil, resulting in a weakened spark. A weakened spark, with a fuel mixture that doesn't want to burn(flooding) and every time you hit the starter you add more fuel to the system. A shot of carb cleaner down the throat may allow it to fire in these situations. I've been told by two performance engine builders that some of today's gas has a higher percentage of ethanol than its supposed to resulting in a lower boiling point-see the snowball effect growing here? Mike

[Don Coatney]

And I feel sorry for Don - never had a boat? I have about 15, need one? In fact, I'm typing this sitting on my sailboat in Texas this morning.

Dont feel sorry for me. I forgot that I once bought a rubber raft for 6 bucks in Columbus, Ohio at K-mart in the 70's, so I really did own a boat for a short while. I got my six bucks worth 100 feet down the river when I hit a rock and sunk:D Raiesd the river level several inches as I recall:rolleyes: I am writing this from my Hotel room in San Antonio,Texas

[Plymouthy Adams]

boat ..just a floating hole in the water to throw money into...

[Don Coatney]

boat ..just a floating hole in the water to throw money into...

Lisa calls my P-15 a money pit. Even though I have not spent any money on it in several years.