premium around here is tuff to get, all the close gas docks have only regular gas......I have to run 92-93 myself so I always take a ride to Oceanside, Long Island (Bay Park Fishing Station).....they have 93 at the dock.......if you have some gas in the boat I will show you how to get there......if not then try to fill it up on the road before it gets to Grovers.........

I will get them to put some in it before they hit Jersey.

I think my tools are in the boat, but if they aren't I can get some. I can adjust the timing and run 89-91 in there if I need to. These engines are only 9.3:1 comp, and they run ice cold so no real detonation issues I don't think.

ETA is Monday morning.

im no expert but 9.3:1 should have no trouble running 89 or even 87. the min compressioon ratio for 91-93 is usually 11:1

I've got the timing turned up right now though. They'll be OK.

i have 9.5.1 and have to run 92 or better

yeah, that is usually the case. My builder says 89 no problem. He is a long ways from here though, so I will take it wasy on her until after I get the settings re adjusted a little.

that doesnt make sense. these boat engines are not much different from car engines. if you go buy a car with a 9.5:1 ratio it will recommend 87 or 89. in my lexus with a compression ratio of 11:1 they recommend 93. it all has to do with timing.

this is straight from wikipedia (it all relates to burn rates of octanes, the higher octanes burn longer thus they burn for the entirety of the stroke vs a smaller compression ratio needs an octane that burns quicker):


Picture a cylinder and its combustion chamber with the piston at the bottom of its stroke containing 1000 cc of air (900 cc in the cylinder plus 100 cc in the combustion chamber). When the piston has moved up to the top of its stroke inside the cylinder, and the remaining volume inside the head or combustion chamber has been reduced to 100 cc, then the compression ratio would be proportionally described as 1000:100, or with fractional reduction, a 10:1 compression ratio.

Justin get back on your computer and get back to your engineering. Please call one of us before attempting to use a wrench

Your Lexus isn't designed to be run like a race motor. Put your Lexus in neutral and bring in to the rev limiter for 10 min, then let us know if it starts pre-igniting at 11:1 on 92 octane