Originally Posted by CanOkie
This might show my newbie side but I set the timing with the vacuum attached to the distributor. I set it to 8BTDC. I truck ran much better and started well enough. I'll test it when it's cold to make sure.
When I realized I forgot to remove and plug the vacuum, I went through the process again (this time I disconnected the vacuum and plugged it). When I disconnected the vacuum line, timing went to 4 after TDC. I adjusted again to 8BTDC, turned off the motor, put everything back together. The truck went back to not starting, idling very high, etc, etc. The timing mark was off the scale. It was not as bad as before but still I couldn't tell you how far. I adjusted the timing by feel then used the timing light to see where I was at. Again, it was back to 8BTDC.
So, is this right? I appreciate any guideance or suggestions.
The choke is hot air and seems to work. It is during the initial cold start the chock valve does not close unless manually closed. When I close by hand and get the truck started, it quickly opens slightly and then when warm, opens the whole way. I wonder if the vacuum diaphragm is defective? I tried tapping the carb and using a lubricant with no success.
Thanks, I appreciate any insight.
Instead of using manifold vacuum that's advancing the timing at idle, find and use a ported vacuum source. That will leave the timing lower at idle and the vacuum advance won't come in until the throttle is opened.
There are cases where the alternator will "back feed" power to the ignition system. The cure for this is to use a diode in the wire that goes to the alternator light on the dash.
The choke sounds like it's working normally- it should
partially open once the truck first starts, just enough to allow the engine to run cleanly. As far as it not closing all the way when the engine is cold, it won't close until the throttle is opened to allow the choke to set. If it's still not closing all the way, as long as the engine starts easily and remains running I wouldn't worry about it. But if you think it might do better closing more and staying on longer, you can adjust it to close more by turning the coil cover.
There's always a chance the timing tab and the line on the damper aren't showing true TDC. DETERMINE TDC
. This will allow you to be sure the timing tab and damper are correctly showing you TDC
MAKE A TIMING TAPE
will let you see the timing beyond what the tab can show you.