What octane fuel are y’all running with your Yamaha Sho? I’ve been running regular 87 but was told I need to be running at least mid grade to premium. I don’t feel I’m getting enough speed with my motor and FX21. I’ve ordered a new prop from Lake Linear Prop out of Georgia to help with performance .

Regular

what rpm & speed u getting out of it.

5880 rpms 65 mph full tourney load.

I would run what Yamaha recommends, nothing more nothing less. I think the SHO 250 is suppose to operate best on 89 octane. Yamaha posts owners manuals for their engines on their website in case if you do not have one. It will tell you what they recommend.

Dealer said 89 so that’s what I run, also only buy Shell or Chevron since I can’t get ethanol free, supposedly their gas is a little better, but who knows.

You have to run 89 to get the full 250’horsepower. Fuel choice isn’t really optional with that motor.

Owners manual calls for 89. I have goofed a time or two and used 87 and per dealer its no big deal here and tgere buy 89 will get you best overall performance.

FX21 is a fairly substantial and heavy boat for the 21 foot size. It is almost the same hull as the old 'I-Class'. You are a little low on what I understand to be my top-end, but not by much. I do need to get my prop re-tuned, but I am getting a similar result, though my tournament load is pretty substantial (with me in it). I max at about 61 - 63 fully loaded with my partner.

Thanks everyone and happy holidays!

89 Octane “PER YAMAHA” (Mid grade). Why open it up to public opinion?

I've been running 89 in mine for years

I run 89 (Valero) in my '19 ZX250, which is close to the same empty weight as the FX21, with the ring free per the Yamaha manual. I typically get between 72-76 mph depending on water and wind conditions.

Pretty close to what I get in mine. I can touch 67 with a full tournament load in the right conditions. What prop are you running?

Personally I'm ok with the top speed but I hate the hole shot on my fx21 in the summer with a tournament load. Thinking about looking into a different prop during warmer weather. Just not something I know much about though.