Posted by Phil T on 10/04/17 - 12:32 PM
#2
Wow, I am shocked.
The 75% verbage sounds terrribly wrong to me.
Your engine has a wide open throttle (WOT) RPM limit of ~5500 rpms.
Classic Montauk's with a 2 stroke Mercury 90 hp report WOT speeds of 42-45 mph. Your boat's performance is horribly wrong. There are several intertwined factors that could be the cause:
Carburetors tuned- If your carburetors are not clean and synched your engine will not perform well.
Propeller - If your engine has the wrong size and pitch prop, it will not perform well. You want a prop that will reach 5500 rpm when running lightly loaded, full fuel and one person.
Mounting - If the engine is not bolted on the transom at the right height your engine many not perform well.
It is important to work on 1 variable at a time. First, check the prop. What is the make and size (part # stamped on the inside of the hub)
Are you on a lake or the bay/ocean?
Edited by Phil T on 10/04/17 - 12:32 PM