2003 25hp nissan 2 cycle question

[Tommy Kelly]

I had to pull the carb. and clean it. This is my 3rd nissan outboard ive owned. This is the first one i've had with a restrictor plate. I had a 15hp,and a 30hp nissan that the gasket for the carb. was a round hole in the center this 25hp has a small slit running vertical in the carb. gasket. The engine runs great but I have never seen a gasket like this. Wouldn't it run better with less restriction behind the carb. I have this 25hp on a 12ft war eagle johnboat so it has plenty of power like it is. With myself and fishing gear in boat it will run 39.7 mph by gps. Has anyone tried opening up the plate and maybe rejetting for more power.

 

[TOHATSU GURU]

Re: 2003 25hp nissan 2 cycle question

Just remove the plate...You will have a 30.

 

[Tommy Kelly]

Re: 2003 25hp nissan 2 cycle question

thanks for the answer. I will get a gasket for the 30 hp. and try it. I had a 30 hp a few years ago that was a fine engine it had the round gasket hole i thought the plate was a restrictor.

 

[dukman]

Re: 2003 25hp nissan 2 cycle question

This is also a question about mods to a Nissan 25 HP 2003 Model. I changed the carb gasket when my motor was practically new and it made a significant difference in performance, but yesterday a guy told me that you could drop the lower unit and trim 1 1/2 to 2 inches off the exhaust tube located inside the upper housing and it would give you another significant increase in performance, i'm not sure i want to get crazy with the dremel tool, but i wanted to know if anyone else had heard of this or could explain what effect shortening the exhaust tube would have??????

 

[eddy2419]

Re: 2003 25hp nissan 2 cycle question

Is a new 30HP gasket required or do you just remove a plate?

 

[Dovekie]

Re: 2003 25hp nissan 2 cycle question

Originally posted by INTERNETOUTBOARDS:<br /> Just remove the plate...You will have a 30.

Is there an engine timing adjustment required if you make this change?<br /><br />Thanks

 

[TOHATSU GURU]

Re: 2003 25hp nissan 2 cycle question

No adjustment needed and if you trim the tube the engine will idle rough.