Modern Vespa

Hello, first time poster here!
I have a new to me 2005 Vespa ET2 that I am trying to get to working order. I had been having some hard starts and bogging issues that I narrowed down to the CDI. Replaced the CDI and it ran great, kill switch started working again and it started right up every time.

Now I am having an intermittent issue. I went to ride the bike to work today, and had to wipe some dew off of the seat. I tried to start it with the electric start, and it started but was barely running. Any gas given and it would rev a bit, then stumble and die. Same with kick starting, it wouldnt rev at all. I even took the fuel line off and sucked on the vacuum line, plenty of fuel from petcock.

I got home from work today and I went to verify the issue still persisted, and it started right up with kick starter. Revved just fine too.

My first guess is some humidity or moisture is getting somewhere it shouldn't.

My question to you- where should I look? I have the service manual for the ET2, but most of the symtom charts are fuel or carb related. I also do not see a clear diagram with labelled wire colors etc.

Should I just go through every connector that I know has to do with ignition, wire brush and heat shrink it?

Wiring diagrams here (early and late models):
https://manuals.wotmeworry.org.uk/Vespa/ET2/

Work some dielectric grease into all connectors that look vulnerable to moisture ingress. Carry some WD-40.

nope

A common misconception. Yes, the dielectric grease is non-conductive (that's what dielectric means) - but the metal to metal contacts cut through it. The idea is to stop any contaminants getting to those contacts and causing corrosion. That works quite well, but filling the contacts with dielectric grease gives even better anti-corrosion protection. All I can say is that my working career was as a hands-on electronics engineer, and dielectric grease was used at every opportunity in systems that had to last more than a few days.

nope

So-called "electrician's" tape was never used. Self-amalgamating tape (AKA rubber (not silicone) 'rescue' tape) was the go-to stuff for connections that had to be directly protected from the elements if sealing heatshrink couldn't be used.

nope

Crimp is good IF you have a good crimping tool, and the heatshrink variety are indeed the best. Soldering is fine IF you also use heatshrink over the joint, which gives it strength, or otherwise support the joint.

One problem that can arise with crimping is when an incorrect size connector, or poor crimping technique cuts through some of the wire strands.

I tend to use the solder+heatshrink method - cheaper and quicker. I only use crimps on things like spade connectors where the joint is expected to be able to be undone.