Yamaha 6 and 8hp differences

[DoubleVision]

I have a 6 hp 2 stroke 1999 vintage Yam outboard with a knackered carb. I`ve heard on the grapevine that it is basically the same engine as the 8hp except the carb and changing the carb for the latter one will convert it indeed to an 8. As I have to buy a new carb anyway if this is true I might as well upgrade. Does anyone know if this can be done and if so are there any other mods that need to be done? Cheers Paul /forums/images/graemlins/smirk.gif

 

[Talbot]

May even be the same carb, but with different jets

 

[seanfoster]

Can't answer your question but there is a really good forum: http://www.marineengine.com/cgi-bin/discus/discus.cgi where someone probably can. I've used it a few times and they've been really helpful

 

[VicS]

It may be true but sometimes there are other differences, in particular with the inlet manifold and reed valves. It is for reasons of that nature that I cannot realistically upgrade a 6hp Evinrude to 8hp. Prop sizes may well differ as well.

Access to comprehensive parts diagrams would indicate what differences exist but unlike Johnson and Evinrude there do not seem to be parts lists available on line for Yamahas.

Another first class source of help and advice are the iBoats forums

 

[charles_reed]

Whilst the basic block and crank are the same there are differences in inlet tracks, carburation, ignition advance mechanism and cooling systems.

Using the same major components for 2 different engines is common practice with 2-stroke OB manufacturers.