Lack of power, Stuttering

[firefightersth]

I have a 65 Monza 110. When starting car has to idle for atleast 10 minutes before putting into gear or it dies. Also while driving when giving more throttle the car first stutters for a second then will take off. This is my first Vair, Seems not to have hardly any power as well. I have replaced spark plugs and wires, also cleanend ends on distributor. Any ideas on what may be causing this?

[flat6_musik]

I'd say most likely the carbs are dirty and in need of rebuilding/sync'ing and the chokes may not be hooked up and set correctly. It's always nice to go through them every so often, especially if the car sets up for months at a time.

[bbodie52]

I have a 65 Monza 110. When starting car has to idle for atleast 10 minutes before putting into gear or it dies. Also while driving when giving more throttle the car first stutters for a second then will take off. This is my first Vair, Seems not to have hardly any power as well. I have replaced spark plugs and wires, also cleanend ends on distributor. Any ideas on what may be causing this?

There is really not enough information here for a complete, accurate diagnosis, other than a probable carburetor problem. The automatic choke mechanism that normally engages when the engine is cold could be malfunctioning or not properly set on one or both carburetors. These circuits are designed to enrichen the fuel mixture and to maintain a fast idle until the engine warms up.

Other fuel enrichening circuits, such as the carburetor accelerator pump in each carburetor, normally injects a squirt of gasoline into the throat of each carburetor when you step on the gas pedal. Carburetors function while driving by creating a vacuum and fuel flow (venturi effect) as air flows through the narrow throat of the carburetor. When you first step on the throttle and open the throttle butterfly, it takes a moment for airflow to be established to draw fuel from the float bowl to mix with the air to establish an appropriate fuel-air mixture. The accelerator pump plunger mechanically squirts a shot of gasoline into the carburetor throat to momentarily enrichen the air with fuel until the venturi effect can get things moving through normal fuel passages. If the accelerator pump(s) are not functioning properly -- there will be no squirt of fuel and the engine will stumble as it "swollows" a burst of air with no gasoline mixed in. You can actually see the accelerator pump function, even with the engine turned off, if you remove the air cleaner assembly and look down the carburetor throat (hold the choke open so you can see), while rapidly opening the throttle manually. You should see a brief jet of fuel squirt into the carburetor throat.

A vacuum leak can also cause this type of problem. There is a metal vacuum balance tube between the two carburetors. A rubber hose connects each end of the tube to the carburetor manifold base. There is also a short rubber tube on each carburetor connecting the base of the carburetor to a vacuum break diaphragm on each choke mechanism. Another rubber hose connects the right carburetor to the distributor vacuum advance (there is a small cap on the other carburetor that closes the vacuum tube on that carburetor, since there is no distributor connection on the left side). There is also a vacuum hose between the balance tube and the Positive Crankcase Ventilation (PCV) system, and if you have an automatic transmission there is another connection between the balance tube and the automatic transmission vacuum modulator.

Finally, a vacuum leak can develop at the base of each carburetor, if there is a flaw in the seal between the carburetor and the intake manifold.

As you can see, there are many possibilities for vacuum leaks to develop. A missing vacuum cap, a split or loose hose, etc. is all it takes, and a significant vacuum leak can create an extremely lean fuel-air mixture that will cause the engine to malfunction, stumble, and run with no power.

Overall, your description of the car stumbling off the line and continuing to run poorly sounds like a vacuum leak would be suspect. You need to perform an inspection to physically check for loose or missing hoses, split hoses, or loose connections. Dont forget to check the automatic transmission vacuum modulator hose at both ends, including under the car on the side of the transmission. You could have a faulty carburetor with an internal malfunction or clogged fuel passage or float bowl problem, but check for an external vacuum leak first. A faulty choke problem would disappear when the engine warms up, and an accelerator pump problem would also disappear once the car is moving steadily at a constant rate of speed, but a vacuum leak problem will remain a problem all the time and will also starve the engine for power due to the continuous lean fuel-air mixture.

I have attached sections of the Corvair shop manual to help you with your troubleshooting, tune-up and repair efforts. If all other searching for a vacuum leak fails to reveal the cause of your problems, a carburetor rebuild or replacement may be needed. But save that for last as you go through fault isolation and troubleshooting procedures.

I hope this helps.

[Mountain Pilot]

A quick hint. While looking for a vacuum leak use a spray bottle with water in it, spray the areas that may have a leak, if so it will draw in the water and make the engine run rougher or kill it altogether...

Best of luck...

[firefightersth]

Thank you all for your input. I have found it to be that the carbs need to be rebuilt.

[bbodie52]

A few of links that might be helpful...

Clark's Corvair Parts (Rebuilt Carburetors and Carburetor Rebuild Kits and Parts)

http://www.corvair.com/user-cgi/catalog ... IN&page=57

California Corvair Parts (Carburetor Rebuild Kits and Parts)

http://www.californiacorvairparts.com/c ... category=8

Corvair Underground
Download Catalog and see Catalog Section C, Pages C-1 thru C-8
http://www.corvairunderground.com/
http://www.corvairunderground.com/news/carbkit.html

eBay
Corvair Premium Rebuilt Carburetors - choose any year 1964 -1969. Guaranteed!
http://www.ebay.com/itm/Corvair-Premium ... 20&vxp=mtr

http://www.ebay.com/itm/Corvair-Perform ... a6&vxp=mtr