Yamaha F25(F20)

[Denkka1980]

Hello,
I am having a yamaha F25 year 2000. In Finland this engine is restricted to a F20 engine.
Now my question is how can I upgrade it to a F25 engine?

I know that the carb need to be changed, but is it someting else I need to do/adjust?

Thanks in advance!

Denkka

[boscoe99]

As near as I can tell the F20 and the F25 are completely different motors.

If Yamaha/Finland modified an F25 so that it produces only 20 horsepower, then they would be the ones to tell you what the modifications were.

I will be very surprised if anyone from here in the US can tell you what needs to be done to put your motor back into its original 25 HP configuration.

Good luck.

[ritiavanne]

it is 25hp

its only taped to 20!
Kipparilehden testissä 6/1999 yamaha f20 potkuriakselilta 25.6 hv, kun esimerkiksi h***an kolmipyttyisessä "vain" 18.3 hv

[TownsendsFJR1300]

That's telling him!


Can anyone translate?

[ritiavanne]

so..

this finnish F20 is F25 without any restrictors. finnish boating magazine "Kippari" tested 20hp engines on issue 6/1999 and Yam F20 was measured 25.6hp from propeller axis. it was only taped to 20 for some tax or registration reasons. btw 3 cylinder honda BF20 - "only" 18.3hp from axis

[rodbolt17]

cant translate finnish nor cryllic.
if I could I would know more about a 1916 finnish mosin nagant I have.
however I do know that here in the US we don't get much information on non US market motors.
what they did to derate it is anyones guess.