Increased engine spray after engine raised
Posted: Mon Aug 22, 2022 11:25 pm
I have mounted a 2001 Yahama 90-HP two-stroke-power-cycle engine on my 1989 Montauk 17 at an engine mounting height of two-holes-up from the original mounting at lowest possible position. An engine mounting height of two-hole-up seems common for this boat-engine combination. The A-V plate is located about 1.5-inches above the hull bottom at the keel. When the boat is on plane at 22-MPH most of the A-V plate is above the water flow.
After the change in engine mounting height, an increase in V-shaped spray coming off the lower unit of the engine can be seen. There is a SONAR transducer mounted on the Starboard side of the transom, but the spray pattern is symmetrical.
From what I read online, the typical fix is to further raise my engine another mounting hole.
Q1: since I already have the AV-plate above water while on a plane, have I not already maximally raise the engine?
When on-plane I've trimmed the engine up to the point just before I hear increased ventilation. I never get to the point of porpoising.
After the change in engine mounting height, an increase in V-shaped spray coming off the lower unit of the engine can be seen. There is a SONAR transducer mounted on the Starboard side of the transom, but the spray pattern is symmetrical.
From what I read online, the typical fix is to further raise my engine another mounting hole.
Q1: since I already have the AV-plate above water while on a plane, have I not already maximally raise the engine?
When on-plane I've trimmed the engine up to the point just before I hear increased ventilation. I never get to the point of porpoising.