Just air coming out exhaust

[duck boat]

Does anyone know why air would be coming out the exhaust and the water stream is not? I have the intakes submerged below water level, but all I feel with my hand is air coming out the exhaust and no stream of water? I have a Johnson 8.0 HP model # JRCCS. I think the motor is from the late 80's.

[Rebel Sympathy]

Is the motor overheating?