I took my trusty old Jato 3.3 (2.5 model) off the shelf, added fuel, and fired it up. Other than fixing a leaky fuel tank o-ring, it ran perfectly at last seasons needle settings. This engine has about 3 gallons through it, and it has a 2-chamber resonator. I got the roller for $20 and the engine for $50 used with six tanks of fuel through it some 5-6 years ago. It's a good runner.