87 or 89 octane?

steplift20 · #1 07-04-2022, 05:58 AM

Since gas prices are do high what are you guys putting in 87 or 89 octane? I have my boat on a trailer so I go to a gas station I don't have to get it on the water. I know 89 is better but is it that much better? Let me know what you put in yours,thanks

spareparts · #2 07-04-2022, 11:25 AM

most older 2 strokes motors are rated for 87, some even as low as 85. But the more modern engines usually require a minimum of 87, with most Yamahas liking 89. The high horsepower Mercs prefer 92, but will derate if the ecu sees and detonation. Check you owners manual

steplift20 · #3 07-04-2022, 02:57 PM

Thanks spare,I will do that,I do have a Mercury Manuel that came with the engine and forgot about it until you mentioned it
I guess sometimes I get lazy, it's easier to post and wait for replies but I'm going to get the book out. And do some searching myself. Thanks again spare . But I'm sure I did in the past and it said put the highest octane availible. But I have to check. That doesn't sound right. They should give me a minimum octane to use

spareparts · #4 07-04-2022, 03:25 PM

You will probably be fine with 87, I drop my total timing by 2 degrees and go up in jet size anytime I go into the carbs of one. Gives me a little breathing room with the lean gas we run nowadays. If you can get e free, regardless of octane, its hard to beat

steplift20 · #5 07-04-2022, 05:10 PM

E free not here in no atleast nowhere by my boat. I just use Startron and hope for the best .im trying to use my boat more often now that I don't have the oil injection system disconnected, one less thing to worry about. And I ketone her in the marina where I launch. So much easier now just have to mix the oil and gas , next I have to install a water pump and maybe a poppet valve .

cfelton · #6 07-10-2022, 05:41 AM

Here in NC we can still buy E free. Most gas stations sell 89 octane. I go to a couple of places and fill all my jugs with 93 E free. Since I still run a 170 Mercruiser inboard thats what I run in it. I don't put ethanol in anything but my pickup trucks. Lawnmowers, weed eaters leaf blowers, and tillers get 93 octane non ethanol. I work on alot of small 2 cycle engines and ethanol will ruin the carbs on small 2 cycle engines. Ethanol is the worst thing thats ever come out. I run 93 ethanol in my 97 Tacoma with 4 ozs. of Lucus injector cleaner every tank full. It just tripped 431000 this morning and still runs perfect.

steplift20 · #7 07-10-2022, 11:45 AM

In NC you can get it but here in nj. I can't. They should atleast give us a option but they don't ,that another reason to get out of nj the only thing that's good with nj is the weather. You get four seasons and I like that. Jersey is a nice place to live but to expensive . I wish I could put e free gas in my boat.
Plus the Tacoma is a Toyota. Case closed.