GT-40 fuel

[hofftoski]

What is the recommendation for octane rating for a 2000 ski nautique .
When shifting from neutral to forward the the engine sounds like it knocks.
Wondering if it is the fuel.
I run 87 octane.


Sent from my 2PQ93 using PLT Nautique mobile app

[charlesml3]

That boat will run just fine on 87 Octane fuel. The knocking you're hearing couldn't be predetonation. That would only happen during hard acceleration, not when you shift into gear.

-Charles

[Fgroce]

Do you think the noise you are hearing is from the rear of the engine. If so your damper plate may be starting to go out. CorrectCraft fan has a lot of people who are good with the older boats. May want to post over there also.

[TTKammer]

The owners manual for my '97 GT-40 says to run 89 octane. Not sure if things changed in the few years between '97 and '00, but it claims that you need to retard the timing if 87 octane is all that is available.