Carter Bbd leaking throttle body
It’s leaking when the engine is shut off. What could that mean?
It means there is fuel leaking onto the top of the throttle plates, or it is boiling off the manifold floor and condensing when it hits the plates.
One of three things;
1) percolation
2) too high a float level
3) faulty parts, or gaskets.
If it does not leak while idling, and the engine idles nice at standard timing and carb settings; that probably rules out #2 and #3.
If after you shut it off it takes more than a minute to appear, then it is probably coming up from the bottom. That would point to evaporation off the manifold floor, which would point to any of the three.
If it appears instantly, that points to #2, or maybe possibly #3
If the choke takes a long time to come off, and the electrical choke element heater is proved to be OK, then the heat crossover under the carb may be plugged; this is a common thing on older engines.Or it may be that the heat-riser valve is seized shut. So check the valve and if it is free, pull the intake and chisel out the carbon. The carbon in there acts as a big heat sink,cooking the carb.
If you pull the intake, you will also need to clean out the chamber underneath it, which requires you to remove the tin splash shield, by removing the rivets which hold it on. That baffle is usually jammed up with carbon as well.
This presents a bit of a problem in how to reattach it afterwards; cuz if the rivets fall out during operation. who knows what kind of damage that might cause.
Up here in the North, we have to have that crossover-system operating in winter, for driveability. In San Diego IDK. If you see temps below freezing there on a regular basis, I would leave it operational. On a stock 318, that manifold heater can be very beneficial.
Ok so
Pop the air cleaner top and with the engine idling, stare down the carb with a flashlite. You should see dry plates and no dripping. While you are there,kill the engine by pulling the blue wire off the ballast resistor, and continue to stare down the bores, at least a minute. You should not see any liquid dripping nor forming on the plates nor any smoke. This rules out #2, and probably #3.
After time is up, disconnect the accelerator pump link-arm by pulling the clip and set the rod asside, then start her up again and let her idle for half a minute to burn off the squirt. Then shut her off and open the throttle wide open and fix them there. Then immediately check the manifold floor for liquid with your flashlite. There should not be any on a fully warmed up engine. Then wait about a minute. There should not be any liquid or smoking. If you get either, badaboom there is your source.
