New alternator and Isolator... no starter cranking
 

I just installed a new one wire alternator and also added an isolator to the system. Now that everything is all hooked up, the engine won't crank.

This looks like it's a Thunderbolt V system.

Here's what I did:
On the new alternator, I connected the old Black cable, and replaced the old orange cable with a new 4 guage cable that goes to the isolator and then the batteries. Since the old orange cable just goes to the starter positive and then battery, this circuit should be fine.
The Purple, purple/red and purple/yellow are tied off and not connected to anything,

would any of this cause the engine to not crank or did I miss something?

According to the diagram, the purple/yel goes to the electric choke... should this be connected to something? I know that this one shouldn't affect the cranking though.

Re: New alternator and Isolator... no starter cranking
 

Without seeing how you went about the wiring it is hard to say but I think you broke the feed from the starters large post that feeds the system IE: the dash ETC. Check to see if you have voltage at the dash. What you should have is the heavy cable coming from the Bat switch to the starter then the red wire coming from the same post on the starter up to the circuit breaker and on to the dash via the main harness. If by chance you disconnected thr red there is your problem.

Phil

Re: New alternator and Isolator... no starter cranking
 

Turned out that the starter issue was due to the throttle lever being out of alignment. Now that that's been corrected, it cranks.

Any idea about the electric choke wire coming off of the alternator? The circuit diagram shows that the wire goes from the alternator to the elec choke and then another wire goes to ground. Couldn't I just wire it up to a 12v swicthed ignition source and be done with it?

Re: New alternator and Isolator... no starter cranking
 

Synack,
For your choke, connect a tee to your oil pressure sender and place a pressure switch in the tee. Feed 12v to the switch on one side and the other to your choke. When you have oil pressure the switch will make and send 12v to the choke. If you have other accessories you want to have powered only when key is on such as switchable tips feed a solenoid with the pressure switch and then run the accessories off the solenoid as the pressure switch will likely not carry a lot of current.

Re: New alternator and Isolator... no starter cranking
 

The oil pressure sender way sounds good.

I was noticing on the Thunderbolt IV, that they wired the elctric choke off of the purple wire at the alternator, which also goes to the + on the coil.

Should I just jumper the purple at the alternator (which goes to my coil) and the purple/yel (which is the choke)? They are both leads that I disconnected off of the alternator.

Re: New alternator and Isolator... no starter cranking
 

You can take power off the coil lead for the choke that works fine.