Exhaust relief holes outboard. These holes allow water to escape from the motor when it is running in shallow water. Nov 16, 2015 · Idle exhaust relief system: As part of its world-class sound-management technology, the 150 FourStroke features a special idle exhaust relief system that uses a low pass acoustic filter to attenuate high frequency exhaust noise at idle speeds. That will increase top rpm (which you desperately need) and improve the hole shot as well. We would like to show you a description here but the site won’t allow us. Sep 21, 2013 · I just drill the lower above the cav. Conclusion The exhaust on an outboard motor is located at the back of the engine, near the Sep 21, 2013 · I just drill the lower above the cav. Jun 3, 2011 · They are just relief holes but the high pressure valves will discharge water out if water pressure gets high enough to open valves. There is a inner housing within it that has a heavy duty seal around the bottom of it, or heavy duty seals around a inner extension between the housing and Mar 13, 2023 · Exhaust Relief Holes Outboard Most outboard motors have exhaust relief holes near the bottom of the motor. They are mainly for idle or low speed when exhaust can't easily go through prop. Removed all gasket and sealer material tonight.