Update Tohatsu 5Hp for 6Hp- carburetor

[Jarda]

Ahoj, koupil jsem neoriginální karburátor pro zvýšení výkonu motoru Tohatsu na 6Hp, ale motor s tímto karburátorem nefunguje dobře, takže hledám chybu a prosím o pomoc, nechci utrácet moje peníze zase na jiném karburátoru. Originální karburátor je Keihin 3R4032001M CARBURETOR ASSY, MFS / NSF6A2, je vybaven tryskami, Main Jet 70, Slow Jet 45. Mohl by někdo změřit průměr klapky v tomto karburátoru, můj má 19mm, ale nevím, jestli by měl nebýt 21 mm?
Tlumič je umístěn na straně karburátoru k přírubě na motoru.

 

[Sea Rider]

Would be nice to translate what posted to English...

Happy Boating​

 

[km1125]

This is what Google Translate tells me it says:

"Hi, I bought a non-genuine carburetor to increase the power of the Tohatsu engine to 6Hp, but the engine with this carburetor does not work well, so I'm looking for a mistake and please help, I don't want to spend my money on another carburetor. The original carburetor is Keihin 3R4032001M CARBURETOR ASSY, MFS / NSF6A2, is equipped with nozzles, Main Jet 70, Slow Jet 45. Could someone measure the diameter of the flap in this carburetor, mine is 19mm, but I do not know if it should not be 21mm?
The damper is located on the carburetor side to the flange on the engine."

 

[pvanv]

3R4-03200-0 was superceded to 3JE032000M

$198.98

 

[Tohatfu]

This is what Google Translate tells me it says:

"Hi, I bought a non-genuine carburetor to increase the power of the Tohatsu engine to 6Hp, but the engine with this carburetor does not work well, so I'm looking for a mistake and please help, I don't want to spend my money on another carburetor. The original carburetor is Keihin 3R4032001M CARBURETOR ASSY, MFS / NSF6A2, is equipped with nozzles, Main Jet 70, Slow Jet 45. Could someone measure the diameter of the flap in this carburetor, mine is 19mm, but I do not know if it should not be 21mm?
The damper is located on the carburetor side to the flange on the engine."

I changed my carb to the 21mm then I took my dremel and ground out all the ports to make them as large and smooth as I possibly could, I also changed my prop by 1 degree and installed a hydrofoil fin. Not only did I gain a decent amount of power, it also runs super smooth. I was under the impression the msf6a2 was a 21mm as well but if not the throttle body is the same for the 4,5 and 6. The difference must be in the jetting. I'm lucky enough to have a buddy that owns a marina, he gave me the 21mm, I'm not sure where it came from. I'll ask and let you know.

 

[km1125]

....I was under the impression the msf6a2 was a 21mm as well but if not the throttle body is the same for the 4,5 and 6. The difference must be in the jetting. ....

The three carbs definitely have a different minimum diameter in the venturi, as well as different jetting.

 

[Sea Rider]

That's whay all 3 carbs are different, have slight narrower or wider fuel passages and jets that accounts for more air/fuel intake. If wating to get he max HP cowl rated a correct prop maximization with less pitch props revving max wot rpm range factory stated it's the way to go. A doel fin won't increase speed, if the deck load is not evenly distributed will make the combo to plane faster and if once on plane the fin does not ride parallel to the water level will increase the lower leg drag. Remove it, distribute your deck load evenly, go full throttle and check if planes fast same as with fin.

Happy Boating​