2004 Ski-Doo Summit 800, Engine idles nicely and then dies after about 10 - 20 seconds.

My uncle passed away in 2011 and my parents inherited his 2004 Summit 800. This thing sat for over a decade before my step-dad tried to get it running. Now in late 2022 I decided I'd give it a shot.

I rebuilt the carbs, replaced in-tank pickup line and fuel filter; fuel tank nipple & grommet; some coolant lines, etc. Little stuff.

Got the thing running with the help of a little carb cleaner into the carbs. Would only run for a little while before dying.

Rebuilt fuel pump & tested–works perfectly.

Before I put the carbs on I had my step-dad turn the engine over a few times while I put my finger on the impulse line. I didn't feel much... machine ran for a little bit before dying. Let it sit a moment... pulled it over a hand full of times and got it running again but very briefly. This tells me that fuel is being consumed faster than it's being replaced. I know the pump is good. I know the pickup line and filter are good. I know the carbs are good (new float valves).

My thinking is the impulse line isn't generating enough suction to pull fuel at a high enough rate.

Anyone have thoughts on what might be going on?

I appreciate all help!!

Jason