98 TRX300FW not starting

A little background:

I’m the second owner of a 98 TRX300FW. I have had it for about 5 years and had no problems until now. Have just done maintenance with guidance from this site using the service manual I downloaded from a link I got here (many thanks!).

My 4+ year old battery finally died so I have been kick starting for about 3 weeks. It was deer season and I didn’t want to mess with it.

Deer season is over so I got around to getting a new battery and, after charging it, I installed it – cleaning wire tabs and applying dielectric grease.
Press the starter and it fires! Great!! Unfortunately it only ran for a 20 seconds and now will not start….but it cranks great. All the fuses are OK. I checked wire connections – all are tight and clean (now).

I have tried starter fluid – nothing.
I pulled the plug, it looks OK and I checked for spark – it seems to be strong.
So I figure it has to be fuel BUT it was running fine before I replaced the battery and was kickstarting it.

I have it home now and have pulled the carburetor. It is dirty and I ordered a rebuild kit but while I’m waiting for it, I wondered if there were any other items I should be looking for??

BTW – I use about 1 tank of fuel per month and fill the quad and my generator from the same gas can. The generator is running fine using the same fuel supplied from the same can – so that should eliminate bad gas or contamination as the culprit.

Thanks for any ideas or theories as to why my otherwise solid machine suddenly gave up on me.

Merry Christmas
Jim