742 timing question

[PepeLp]

Hi, I've got a 742 skid steer. I recently switched to a Pertronix ignition and converted it to an electric fuel pump. I followed the instructions in the manual to set the timing: Disconnect the vac advance. Plug it. Set timing at idle. I set the timing at 8 degrees according to the Pertronix instructions. When I reattach the vac advance hose, the timing at idle goes to about 22 degrees! It comes back down at normal operation speed. Is this normal? It seems strange. Thanks!

 

[craigb93]

You have it just right. Engine load causes the engine vacuum to fall and Retard the timing. (Factory setting is 10 deg BTC.)