Simple solid plastic plug designed to be installed without removing your sterndrive. If you are interested in this offer, you, most likely opened a Pandora Box on the upper part of your Cobra sterndrive. The original, so-called (removable version) is pictured here and priced at $75 for the set and will require access to the back of the sterndrive's water passage to secure the metal wedge from the inside.
Just like everyone else I opened the water passage plug. I did not have a luxury of removing my drive and had to come-up with a quick solution to close the gaping hole in the drive. I went to the store and picked up rubber plug which sealed this hole mighty tight. Little did I know, after taking my boat on to the open water and running my engines at a speeds above 2500 RPM the engines became rapidly overheated. I take good care of my engines and risers and they are all new and work very well. The engines where starving for water. The issue at hand was the narrow water passage I've created by installing deep plug. I had to go back to OEM designed plug. But OEM plug has issues. First issue is very thin and brittle plastic insulator ring. This ring serves several functions; cover the hole and isolate stainless steel rear wedge and screw from touching an aluminum sterndrive case to prevent electrostatic corrosion. In addition, phenolic gasket isolator must be installed on to the stainless steel wedge to prevent it from touching inner wall of the drive. Stupid and overcomplicated. It should of being just "plastic" from the get-go, just like a gimbal water passage adapter. It is completely plastic with a plastic screw just 5 inches away from this pesky plug. 9xmarine plug I designed is inert. No conductivity of any kind.
It's 3D printed permanent threaded plug which needs to be install using OEM rubber ring, The material used is PETG. It is the same material spring water bottles are made, but not transparent and extremely compacted. if you installing "on the water", under water cure-able silicone is fine, or JB Weld when installing on a dry dock. JB Weld is preferred. Another benefit of our plastic plug is it's not electro-conductive and will not react with aluminum drive material. See provided instructions.
1. After permanently installing our plug, have a stern drive's impeller pump the water to the engine for a few minutes. Shut the engine off and examine the internal connection between rubber hose from gimbal assembly and Cobra's engine small round oil cooler. Look in to the oil cooler for any accumulated foreign debris and if the inner grid is unobstructed.
2. Our threaded round plug has 4 indentations designed for a needle nose players. However, we recommend to drill one of these opening through the plug before permanent installation. The drilled hole will serve as a pressure relief when plug-ready cavity is filled with JB Weld or other Gasket silicone. While plastic plug is rotated in to its permanent place, excess uncured material will be squeezed out from this pressure relief hole living just enough on the inside. Plus round plastic washer will prevent extra material escaping into the drive's water passage.