1998 Nissan 25hp

KB18

Recruit
Joined
Jul 1, 2021
Messages
1
I’m wanting to convert my 25hp to a 30hp. What all will I need parts wise? What all is required?
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,559
You did not mention model. Year is irrelevant. If it's an old 2-stroke, such as an M25C3, just remove the intake gasket restrictor and reset timing. If it's a 4-stroke, you need a different ECU. Luis has a complete procedure elswhere on this board.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
You did not mention model. Year is irrelevant. If it's an old 2-stroke, such as an M25C3, just remove the intake gasket restrictor and reset timing. If it's a 4-stroke, you need a different ECU. Luis has a complete procedure elswhere on this board.
To start with must swap the M25 carb/intake gasket for the M30 gasket which has a larger internal dimeter to allow more air intake and advance the timing from 20 deg to 25 deg. This mod should have its own stickie as it's asked a lot here. Check Tohatsu 25 to 30 HP conversion under Find Threads or Search Forums....

Happy Boating
 
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