Gasoline Octane

[HoustonPerson 0]

Somehow I discovered on the Indmar web site that the correct octane for the Monsoon in my boat is 89 - not the 87 I have been using the first year.

Apparently, this is true according to my most recent post over at MBO. So I will be changing to the middle grade gasoline to see how it goes.

What octane do you use and what engine?

(Oh man, no speel cheeker, this will get baad quikc, even wiht it - its baad)

[CarveItUp 0]

I've generally been using 89 with the occasional 87 thrown in when I forget to tell the gas jockey the right octane.

I have the Monsoon II...

[WakeAndSno 0]

I have the monsoon and use primarily 87 octane. I haven't really noticed much of a difference bumping up to midgrade... Worst case it will cause some more knocking (I think) - and we have a sensor for that

JZ

[Brad B 56]

Lowest the marina has is 89.

But for the 2 or 3 times I pull it off the lake, I'll use 87.

[HoustonPerson 0]

Brad weren't u supposed to email me some nice pictures of the ladies?

[Slider 0]

I have read that the CPUs in our boats will actually retard the timing slightly to compensate if we run 91. The Malibu CPUs are set up for 89. 87 octane is burn slightly cooler and tend to build up a little more carbon in the engine. In the long run this will decrease engine life and fuel economy. As for my boat we burn 89 for these reasons and so that if anything untowards happens we will have followed the recommendations as close as we can.

Joe

[stewart 18]

My HH 383 loves VP Race gas, unleaded, of course

[UWSkier 3,777]

I've actually noticed a 2-300 RPM difference at WOT when using 87 versus 89. I attribute this to retarded spark timing. We typically run 89 for the first tank every year, then 87 after that. We try to run a can of Sea Foam through once a summer too just to keep the carbon buildup to a minimum and to keep those injectors free of debris and gunk.

[Malibudude 1,072]

I usually use 89' as recommended but if it's 87 or 91 on the water I'll use 87.

[wakeace 0]

I have been using 89 but it sounds like quite a few are using 87.

[gooddog 1]

I started out using the premium when I first got the boat (w/Monsoon 325)but later I tried a tank of regular old regular. I couldn't tell the difference, so now I buy the cheapest gas I can find and it works great.

[BillFooter 50]

Hammerhead 365 and 89 octane.

[whiteVLX 0]

I generally run one or two tanks of 89 throughout the year and usually fill up with 89 for layup, otherwise 87 is fine for me and I have yet to notice any side effects.

[VinRLX 5]

89 only for my Monsoon. I like shooting for the optimal performance, even if it is a few nickels more.

[DC9669 0]

On the Monsoon use 89 octane for maximum performance. On hot days if you use 87 the timing will retard slighty to allow for the hotter 87 octane gas. You probably couldn't tell any difference when riding in it though. Higher octane gas burns cooler than lower octane.

[tvano 831]

i was running 87 and noticed an occassional backfire so i bumped to 89.

backfire still there. perhaps 1 in 10 or 1 in 15 during power up. we do lotsa idling (to heat water for a shower in michigan) so i have been wondering if that is a problem. 2004 LCR. anyone else backfiring?

[Boomer 1]

Always ran 87 in my '04 Supra, with Indmar 320 (rated for 89.) Ran perfect. I've ran only 89 in the Bu so far though.

[VinRLX 5]

i was running 87 and noticed an occassional backfire so i bumped to 89.

backfire still there.  perhaps 1 in 10 or 1 in 15 during power up.  we do lotsa idling (to heat water for a shower in michigan) so i have been wondering if that is a problem.  2004 LCR.  anyone else backfiring?

<{POST_SNAPBACK}>

IIRC, you don't have a sensor to change the timing on the LCR. Jerry (Sunrise) can jump in here.

[tvano 831]

i was running 87 and noticed an occassional backfire so i bumped to 89.

backfire still there.  perhaps 1 in 10 or 1 in 15 during power up.  we do lotsa idling (to heat water for a shower in michigan) so i have been wondering if that is a problem.  2004 LCR.  anyone else backfiring?

<{POST_SNAPBACK}>

IIRC, you don't have a sensor to change the timing on the LCR. Jerry (Sunrise) can jump in here.

<{POST_SNAPBACK}>

true, no knock sensor.

[jeffmx 37]

I always run premium... but when it hits $4.00 a gallon, I may change my tune !!!

[Wkerat 3]

lake has 89 so I do that on the water, but 93 otherwise. I have done this with the monsoon and now my hammerhead.

[88Skier 1]

They only sell 93 at my end of the lake so that's what I use. My engine's low tech though, so it may not matter as long as I use the min. reqs.

[hbrew 0]

We have the LCR and always use 89.

[MARiley 8]

it all depends on the mood i'm in. 89 most of the time. some days it's 91. always the lowest possible from the dock pumps(usually 87). dock prices are so friggin' pricey. one marina last year at shasta it was 3.38/gal. that was an expensive tank.

[jvianco 0]

I've got the Monsoon 325, and I usually run mid-grade in it. Out of habit of fueling the truck, I mistakenly put the lower-grade stuff in the boat the first time out this year.