Converting Mariner 2HP to 3.5

[BAtoo]

How easy is it to convert the 2hp to 3.5 - is it simply installing a new carb jet or is there more to it?? Cant find anything on google!

Thanks in advance /forums/images/graemlins/smile.gif

 

[Guest]

[ QUOTE ]
How easy is it to convert the 2hp to 3.5 - is it simply installing a new carb jet or is there more to it?? Cant find anything on google!

Thanks in advance /forums/images/graemlins/smile.gif

[/ QUOTE ]

I was told its the choke size ... carb ! That they are esentially same engine .... but it's most likely the jets !!

 

[Heckler]

suzuki 2.2, basically all the same I was told, just a bigger carb, hmm, when i checked the port is the limiting size and that is cast in so not a chance!!
Stu

 

[Clyde_Wanderer]

No point in rejetting if the choke venturi is not any larger as the volume of airflow over the main jet wont be enough to draw the extra fuel possible by the larger jet, and the fuel /air mixture wont be metered proporly causing running problems in the lower end of the rev range, just above tickover speed., and too weak at the higher rev range end.

 

[Haven't-a-Clue]

You might try googling for one of the specialist m/cycle tuners esp. 2-stroke ie Stan Stevens as they have found some innovative ways of getting around choke restrictors as fitted to UK spec mopeds. Worth a try.

 

[Clyde_Wanderer]

Stu, its not a big job to enlarge the transfer ports, but you must radius the edge where they enter the cyl or the sharp edges will beak the rings.
Another way is to raise the ports by a couple of mil, both transfer (inlet) and exaust.

 

[Haven't-a-Clue]

Ar, takes me back, that does, files and radiusing! Er, unless I misread the post (probably) he's refering to the inlet port just downstream of the carb. If so, there's probaly a cast ring just inside which if made from the same material as the head, can be (carefully!) ground away with a Dremmel or some such. This will effectively enlarge the port and then a re-jet and away yer go!

 

[Heckler]

ahem, i used to be mechanic for gary bryan before his big smash at oulton park back in the 70s, used to know stan stevens by the way to the other poster, is he still around? so no need to explain about porting thank you very much!
the prob with the port is that the carb stub is too small and it is cast into the cylinder, as another said pointless if the stub is to small.
Stu

 

[misterg]

[ QUOTE ]
How easy is it to convert the 2hp to 3.5 - is it simply installing a new carb jet or is there more to it?? Cant find anything on google!

[/ QUOTE ]

On our mariner 2.2 (black, ca 2003), the restriction is the throttle slide, which is too long to be raised completely - it hits the cap on the top of the carb at about half throttle.

For those that want to know , it is possible to cut it down, and bend the throttle linkage to give full travel. Definitely adds more 'pep', but I believe the 3.5 has a different final drive gear ratio (and neutral) - I certainly experience cavitation if pushing it to full throttle on our rubber duck. I don't think I'd bother again, unless you've got something very sleek and light to push along.

Don't know if jet is different (don't see why it should be) - ours seems happy enough doing the regular 5 minute journey to/from mooring after this mod, but not at anything like full throttle. It must be different from Stu's Suzuki, as the carb is separate (a normal small carb, not cast in).

(Sorry if this appears twice - I thought I had replied, but I think it went into the 'petit mal' that the server has every night just after 23:30)

Andy

 

[Guest]

I was only told that the Choke is smaller on the 2 ... and it was possible to change it ... I was also told that older carbs had an insert tha could be removed to do this ...

Having never done it - was only repeating the Outboard Dealers words ... he services the things - so I had no reason to doubt !!

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[BAtoo]

Thanks guys for your comments; carb doesnt seem to have an insert to remove - but it might be possible to open it out a bit......might have a go or I might try & find 2nd hand 3.5 carb; anything involving the exhaust ports seems a bit involved so far.
Stan Stevens seems to still be tuning 2-s bikes but i think thats a bit beyond the possible benefits. /forums/images/graemlins/confused.gif

 

[misterg]

Take off the plastic 'control' panel so that you can look into the carb throat. Check how far the air slide actually opens when the lever is at full speed - it should clear (or very nearly clear) the venturi, otherwise it's restricted.

See my post above....

Andy /forums/images/graemlins/grin.gif

 

[whisper]

Yes, 3.5 has Forward and Neutral gears, unlike the 2.5.

 

[Lakesailor]

I think they have moved it to 23.40 now. That's a big improvement - not.

 

[Colvic Watson]

[ QUOTE ]
How easy is it to convert the 2hp to 3.5

[/ QUOTE ] Try ebay /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif