Re: Hard to re-start

Posted by Tim Cole On 2012/8/22 17:25:13

Dear Rev:

Here is a standard proceedure for isolating a hot starting problem.

a) A KD spark tester from NAPA will let you check for continuous ignition. The spark should be regular with four beats per revolution from the coil. You should have at least 20Kv when connected to ground.

b) Pump the accelerator and check for fuel. Use a squirt oil can to prime the carburetor. This will isolate a fuel problem.

c) Put your hand over the carburetor and crank the motor. You should have suction. If not, do a compression test and check the cranking vacuum. It should have at least 80psi and 2-5 inhg cranking vacuum. Cranking speed is also important. Too fast means low compression.

d) Another cause is ignition timing. The timing marks need to be carefully cleaned and the timing set to specification. I have found that Packards need proper timing. Timing by "ear" just doesn't work. The marks on these Packards can be very hard to find and if somebody has gone crazy with paint and sandpaper that is a big problem. You can get cylinder number one to TDC and carefully remove the paint with thinner. I have had to spend hours on this detail in some cases.

e) Finally, the proper way to start a downdraft carbureted motor when hot is to floorboard the accelerator. Packard specified that extended cranking may be required with a hot motor.

Hope this helps