Starter Cranks - But doesn't always start right up???

[Syncro Jael]

1987 Syncro
2.1 WBX
New Starter GW Reduction
All wires connections checked.

We have not looked into the ignition switch yet.

This starting problem has plagued my sons Syncro ever since he acquired it. When the weather is cold his Bosch starter would not click or even turn over. The colder it was, the symptoms got worse. If he held the ignition key on for some time or tried starting several times (50) or so, it would engage the starter. I told him that the solenoid was sticking and needed a new starter. Once it warmed up it would start but still needed to crank a bit before it would fire up.

So I purchased him a new GW gear reduction starter and put it in. Now it cranks easily at the touch of the ignition key, but it still has to crank for a while before firing up. I tried it myself and it seemed to fire just when you release the key from trying the starter.

I am guessing there is a voltage drop somewhere or the ignition switch may be at fault.

He would like a push button for the starter wired up and that should be easy to do by tapping the RED and BLKRD wires from the ignition to a starter button.

Any ideas from those who have had issues like this?
Yes, all the grounds have been cleaned and checked.
Yes, the wires to the starter post have been checked.
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1987 Syncro Westfalia Hightop - NAHT
Subaru EJ25 Forged Frankenmotor, Triple Knob.
Jael = (Mountain Goat)

[Ahwahnee]

[Waldemar Sikorski]

Consider a starter relay kit: https://www.busdepot.com/wr1
Is the battery good and fully charged? Check the fuel pressure at the tee. My fuel pressure regulator would not hold pressure after turning the engine off. The fuel pump valve seems to be OK.