Reply
 
Thread Tools Search this Thread
 
Old 11 June 2018, 12:05   #1
Member
 
Country: UK - Wales
Length: 3m +
Join Date: Jun 2018
Posts: 2
Tohatsu 25hk

I habe a Tohatsu 25hk two stroke (i belive it is a 2003 mod) and i would like to get it op to 30hp. I have heard that you only need to change the gasket between the carbuerator and the cylinder. Is this true or do i also need to change the main jet?
__________________

__________________
jonaseriksen01 is offline   Reply With Quote
Old 11 June 2018, 16:54   #2
Member
 
spartacus's Avatar
 
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 60hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 3,465
RIBase
Welcome to the forum.

You need to do a little detective work to answer your question. Tohastu outboards, especially 2-stroke can be tweaked. My M60C uses the same block of the M70C and the only difference is the main advance arm needs adjustment to allow full throttle opening.

On the 25hp, 2-cylinder block you'll need to cross check against the 30hp to ensure it doesnt have an increased exhaust manifold, restricted carbs, or indeed a different inlet reed valve.

2003 25hp
https://www.boats.net/catalog/nissan...-stroke-nissan

2003 30hp
https://www.boats.net/catalog/nissan...-stroke-nissan
__________________

__________________
Is that with or without VAT?
spartacus is offline   Reply With Quote
Old 11 June 2018, 17:17   #3
Member
 
Country: UK - Wales
Length: 3m +
Join Date: Jun 2018
Posts: 2
Thank you on a norwegian site they explained that it is a gasket restricktor (didn't manage to upload it here), if there is a gasket type restrictor on my engine will i need to upjet?
__________________
jonaseriksen01 is offline   Reply With Quote
Old 11 June 2018, 20:03   #4
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: 2 stroke YAM 20 HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 10,475
Quote:
Originally Posted by jonaseriksen01 View Post
Thank you on a norwegian site they explained that it is a gasket restricktor (didn't manage to upload it here), if there is a gasket type restrictor on my engine will i need to upjet?


The only way to be sure is to get the parts diagrams out and compare side by side.
__________________
Poly is offline   Reply With Quote
Old 13 June 2018, 02:14   #5
Member
 
Roflhat's Avatar
 
Country: UK - Scotland
Town: Isle of Lewis
Make: Ceasar Thundercat
Length: 4m +
Engine: Yamaha 70ces
Join Date: Jul 2010
Posts: 734
RIBase
I think you are correct in saying it's just a gasket behind the carb, you can either order a 30hp or just open up the 25hp I believe. I've never done but remember reading on another forum, maybe worth checking the parts book for both engines, just quickly check exhaust part numbers and maybe jets too
__________________
Roflhat is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 07:31.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.