64' Spyder stalls when hot

[vanern]

Our 64' Spyder will start and run, though a little roughly. Once it warms up it will eventually stall and not restart until it cools down. I've replaced the plugs, wires and coil with no improvement. I'm thinking it's vapor lock caused by the fuel pump. The fuel pump was replaced 2 years ago with an AC Delco pump, but I've read that there has been an issue with pump failure in the past. Can anyone tell me if I'm on the right track?

[bbodie52]

Welcome to the Corvair Forum!

Vapor lock would certainly be a possibility. In the history of your Corvair Spyder, has this been a problem in the past, or did it just start occurring recently? If it just started occurring recently, was any work done on the car recently that might coincide with the start of this new problem? Also, does your Spyder have a gasoline filter that includes a fuel return line to the gas tank? The normal filter, which was only found on the turbocharged Corvair, can be seen in the pictures below. It is located to the left of the air cleaner assembly.





When the engine stalls, have you tried performing any tests or examining the carburetor to see if it still contains gasoline? Have you tried disconnecting the fuel feed line at the connection point to the carburetor and performing a fuel volume delivery test by cranking the engine and measuring the fuel pumped from the fuel pump at cranking speed? The shop manual specification for this test is 1 pint in 40 seconds or less. The fuel pump test procedures are shown in the shop manual pages below…



One more nugget of information...

The fuel return line "Z" shown below was added during the final few years of Corvair production. This fuel line runs from a "cross" 4-way connector at the fuel pump outlet. This small diameter fuel line is more restrictive than the lines routed to the carburetors. It permits a small but continual flow of gasoline to return to the fuel tank. Without it the fuel pump goes into NEUTRAL whenever the float bowls are full and the needle/seat valves are closed. This stops the flow of gasoline until the engine consumes enough gasoline to restore the fuel flow back into the float bowls again. By adding the fuel return line, some gasoline is constantly flowing through the fuel pump feed line from the fuel tank and then back again through the return line. Keeping a constant flow of fuel moving uses the cool liquid to cool the steel fuel feed line "D" to help prevent vapor lock.

This vapor return line that was added in 1967 was similar in operation to the fuel return line to the gas tank from the fuel filter that was included with turbocharged Corvairs. The issue is heat buildup in the fuel lines with gasoline that was physically not moving. It was possible for enough heat to be transferred to the fuel to cause it to vaporize (causing vapor lock). The solution added by engineers in 1967 basically copied an earlier solution that they felt was needed to support the hot turbocharged engine. If your fuel lines are physically coming in contact with adjacent metal engine components it might be possible that this additional heat transfer could be causing vapor lock in your engine and causing it to stall. You should check the fuel lines to determine if any of them have physically shifted in a way that would bring them into contact with an engine component that might be causing physical heat transfer. If you have a fuel filter with a fuel return line you should check to verify that none of the fuel lines are plugged or blocked, to ensure that the fuel in the lines remains in motion even when the Carter YH carburetor float bowl is full.



I haven't owned a turbocharged Corvair since the early 1970s, so I'm really not up to speed on maintenance and troubleshooting of the Carter YH carburetor (which tends to be difficult to tune and has a reputation of being temperamental). If your ignition system checks out and is still providing a good spark to each spark plug when the engine stalls — apparently due to the possible heat related issues — you should look at the fuel pump delivery to see if vapor lock appears to be an issue. If fuel delivery is good and you can't find any areas that might be causing vapor lock, there may be an issue with the carburetor. Hopefully some turbocharged Corvair owners will chime in here with additional troubleshooting recommendations.

Carter YH.pdf

Carter YH Carburetor

(1.85 MiB) Downloaded 29 times

Also, is there anything about your ignition system that is not standard or has been modified (such as electronic ignition)? If the distributor configuration is standard, using points and condenser, have you checked the condition of the points and the point gap (dwell)? There is a special resistor wire in the primary ignition circuit wiring harness. Sometimes these resistor wires begin to fail and start to overheat. Resistance generally increases as a resistor heats up. You may want to check the voltage feed to the ignition coil. With the key on and the points closed, the output voltage from the coil should read approximately 7 V DC.

The link below will provide you with a list of useful websites that are Corvair-related. Some of the links will lead you to an extensive technical library that will allow you to download shop manuals and other technical references in Adobe Reader format at no cost. There is also a link that will help you to locate nearby CORSA (Corvair Society of America) club chapters. While the Corvair Forum can be very helpful as you work on your Corvair, having local friends and contacts in your region who are knowledgeable about the Corvair can also be very helpful. These family-friendly CORSA chapters often offer picnics, group scenic drives, technical training and assistance, car shows, and competition events that can greatly enhance your enjoyment of Corvair ownership. You will also find a list of essential Corvair parts suppliers. Clark's Corvair Parts is the biggest and oldest Corvair supplier in the world. You will find a link that can provide you with a series of videos that amount to a tour of the Clark's Corvair Parts facilities. I think you will be amazed at the quality of the reproduction components they offer — particularly the interior carpeting and re-upholstery items. Parts suppliers such as this truly make our Corvair hobby possible.

Common and Useful Corvair Websites

http://www.corvairforum.com/forum/viewt ... 225&t=6007

I would like to encourage you to expand on your initial post and tell us more about yourself, your Corvair, and your goals for the Corvair. If you can describe your personal assessment of your mechanical skills and abilities, that would help a lot. Members of the Corvair Forum love to be helpful in assisting other Corvair owners with technical support and advice, but it helps a lot if we have some understanding of your technical background and mechanical abilities, Corvair-related knowledge, etc. Helping us to know more about you will help us to write comments to you that are tailored to your needs and experience. Knowing your location is also useful, because knowing where you live can sometimes suggest possibilities.

[skipvair]

I chased a similar problem on a 140, and one night opened the hood when it was about to stall revealing a christmas tree of sparks surrounding my new plug wires. It was the wires in the end. They were about new (5k miles or less) Just a thought.

[erco]

Such a lovely pic of that 150HP motor Brad shared... except for the flipped-over fanbelt. AFAIK all slotted belts have the slots inside, or is this something different? Everything else in the pic is flawless so I have to ask.

[joelsplace]

Belt is fine. Some were like that.

[flat6_musik]

Vapor lock is a no-fuel condition. A quick way to determine whether you're starving for fuel or flooding is to remove the air cleaner cover after the engine shuts down and give a shot of starting fluid. If it starts, you're out of fuel,, if not,, it's probably flooded. Chances are, your YH carb is getting fuel and running super rich, eventually flooding the motor out once warm. The YH carb sucks as it is; you should have it gone through by a reputable rebuilder.

Another possibility is that your fuel tank sock filter is plugged up and starves the engine for fuel after a few minutes.

But first!!.....if flooded,, make sure your fuel return line isn't plugged up.