Increasing HP on 2 stroke Nissan 8

[svchama]

Can anyone tell me how to increase the horsepower on my 1996 8 HP Nissan? I have been told that it just a matter of a new carb jet. Thanks

 

[TOHATSU GURU]

Re: Increasing HP on 2 stroke Nissan 8

What's the serial number of the engine?

 

[svchama]

Re: Increasing HP on 2 stroke Nissan 8

Actually I have two NS8B engines because a friend recently sold me his to use as a backup. The serial number of the primary engine is 3B2-1 65343 and the other one (which needs new seals) is 3B2-1 25219

 

[boatster]

Re: Increasing HP on 2 stroke Nissan 8

That would be great! I have an 8 hp also.<br /><br />Mine is a Tohatsu M8b ser# 3b2 47175... I'm not sure if there are more numbers because the tag is partially chewed. <br /><br />Would an upgrade make this a 9.9 hp? I could really use the extra 1.9. Thanks.

 

[boatster]

Re: Increasing HP on 2 stroke Nissan 8

Hi Elvin,<br /><br />Is it possible to squeeze an extra 2 hp out of these motors? If so would it just be a matter of the carb jets? Thanks.

 

[boatster]

Re: Increasing HP on 2 stroke Nissan 8

 

[phatmanmike]

Re: Increasing HP on 2 stroke Nissan 8

increasing the amount of fuel without increasing the amount of air will not gain you any horsepower. in fact it will make you run worse. its called running rich

 

[TOHATSU GURU]

Re: Increasing HP on 2 stroke Nissan 8

The blocks and heads are different on the 8's and 9.8's. The carb shares the same body but, does have different jets and nozzles. While many outboards share the same basic design and often appear to be the same...sometimes the differences are difficult to overcome without spending a lot of money. On other models the differences can and sometimes are as simple as timing, throttle stops, timing cams and jets.

 

[MOTION LINE]

Re: Increasing HP on 2 stroke Nissan 8

Hi, Change the exhaust cover, port the middle inlet port, drill the carb oversized and change the main jet accordingly, you will have well over 10 hp! Simple and very cheap!

 

[TOHATSU GURU]

Re: Increasing HP on 2 stroke Nissan 8

My forehead is now brusied and my desk top has a crack.

 

[JB]

Re: Increasing HP on 2 stroke Nissan 8

You have my sympathy, Elvin.<br /><br />SVChama: It is good that you have a backup. If you do what Bolaget suggests you will need it.<br /><br />Change the exhaust cover to what? What does "port the middle inlet port" mean? Drill the carb to what "oversize"? Change the main jet to what?<br /><br />None of the above are simple. To do any of them requires engineering knowledge. None of them are cheap. They require teardown of the engine and in some cases, special tools.<br /><br />None of them will measurably increase performance without other modifications to allow higher rpm.<br /><br />ELVIN knows whereof he speaks. His advice is good.

 

[MOTION LINE]

Re: Increasing HP on 2 stroke Nissan 8

Change the the exhausts cover to the the part from the 9.8 hp. engine, If you do not know what middle port is then you´d better forget the mods.<br />The carb can safely be drilled to 10% oversize and increase the main jet accordingly.<br />Theese mods makes the engine a kind of a rever and the middle RPMs will suffer, it is always a compromise, and I trust the Factory, have you ever considered that by tuning the engine you will also get an rude screamer and sooner or later you will get fed up listenng to it??