tohatsu 50 - yamaha 70 carbs?

[Roflhat]

I'm sure this has been brought up before but I can't find the thread?

Basically I'm wanting to put yamaha 70 carbs on my Tohatsu 50 D2, how easy is it to do? anyone done it? do they require re-jetting?

Thanks!

[Roflhat]

theyre from a 1997 model

[omcstratos]

I don't know if/how they will fit, but you will have to play around with jets with any kind of changes you make to get the most out of it.

[Roflhat]

thanks for the reply, yeh i've heard i'll need to change some of the jets. don't know what to yet though.

[Fast Fred]

they bolt on, main jet, it's been a wile, should have a 130-135 main in the 50hp carbs, 145 for the 70 carbs on a 50hp. you maybe able to lean on her more at 140, but start with 145's

[Roflhat]

Hey Fred, was hoping you'd chime in! Thanks for the advice. I've heard there's some benefit to widening the reed block when going to 70hp carbs?

[Fast Fred]

i set the 70hp gasket on the intake, scribe it on the intake, then use a flap wheel to open it up. i take the time to check that the carbs lines up on the intake, look down the carb with the throttle plate open makin sure no intake is in the way, straight clean shot.

[Roflhat]

sounds good, ill give it a go. Do the stock 70hp linkages work? I've got a fuel pump sorted for them

[Fast Fred]

the gang link matches the intake used, 50hp intake = 50hp gang link.

the yamaha 50 is just a bit smaller, the same jets as above work for 70 carbs on a 50 yamaha, 150psi is the cut off for pump gas, at 180psi on pump she will prelight the fuel,
squish band style is best, positive style is needed to meet the curved piston dome.

nisson , hotsu cranks should be welded, mains and throws, the pigtail on the wrist pin clips should be removed, best clipped with snips for a no heat used removale

[Roflhat]

thanks for the replies Fred! Daft question - what's the gang link?

I've read somewhere that only the round bowl carbs bolt on? these are the square bowl ones (1997) does that change anything?