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PeteS
08-18-2005, 09:51 AM
After poking through my manual the other day I found the below page. I've always run 89 in my boat as I've assumed that the AKI is very similar to the (R+M)/2 method of determining minimum octane ratings.

Would I be correct in assuming that, or would the index determined through the research method, or 93, be what they're calling for to run?

Hopefully this topic will help others out with our era boat as well.

OSUspenc99
08-18-2005, 02:45 PM
I was wondering the same thing. I just bought my boat and put one tank of 87 in there. Is that the wrong gas to be using?

RobertT
08-18-2005, 03:05 PM
If I remember right, reading from my manual, you can use 87 in all current MC motors except for the LQ9....which requires 92.

Can somebody confirm?

Tom023
08-18-2005, 03:06 PM
I have a 2001 LTR and it requires 89

east tx skier
08-18-2005, 03:17 PM
With the exception of some of the higher end motors, 89 octane is recommended. If you're fuel injected, you can run 87 and the timing will be automatically retarded. If you're carb'd, you can get away with running 87 (I did it before I realized it needed 89). Predetonation is a risk with this practice though.

PeteS
08-18-2005, 03:50 PM
Hope the baby is doing well, Doug! Like you said, you can get away with 87, although according to my manual your timing may need to be adjusted to accomidate the faster ignition.

I was curious because the way they phrase it above is, "93 RON" fuel is reccomended. Is 89 (R+M)/2 at the pump equivalent to 93 RON?

erkoehler
08-18-2005, 03:54 PM
I can say that I have been running 87 all summer without any issues, but my boat is EFI.

Hoff1
08-18-2005, 04:31 PM
I've been running primarily 87 octane for 5 seasons without any visible issues (but the invisible ones are the ones that count). I never hear the pinging of predetonation unless I have the boat super loaded for wakeboarding, which I haven't done in years. I don't think 93 octane will fix that though. Under most circumstances, I think I'm alright.

Jim@BAWS
08-18-2005, 06:26 PM
This seems to be an ongoing discussion that never seems to end.
87 is all you need in the good old FORD 351. A tank of 93 every now and then does'nt hurt especially if it is AMOCO or BP WHITE gas. Additives like TECHRON in the Chevron product seems to help. With the price of
gas so damn high why put in the expensive stuff. None of us are running
4 cylinders in our boats. The LQ-9 has a reccomendation for min of 89
but will self adjust to 87. as does the 8.1. We just SOLD a CUSTOM 2006 Prostar 190 with a L-18 in it Mini tower, all red white and blue Special Graphics. AWESOME I will try and post some pictures of this animal.

Additives have had a topic of conversation in the past. I started a thread months ago on a product call K-100. The stuff is AWESOME. Nothing but
postive feedback from customers. Fuel gauges working again. Better performance. The others like STABIL and SEAFOAM can't touch this product.


Jim@BAWS

erkoehler
08-18-2005, 06:28 PM
where can we get the K-100?

bucky
08-18-2005, 08:46 PM
I ran one tank of 87, normally run 91 or 93. The only difference to me was a loss of ~350 rpm on the top end. Since I'm already paying $2.65 for regular, The extra $.15 a gallon doesn't make as big a difference as it did when gas was $1



I can say that I have been running 87 all summer without any issues, but my boat is EFI.

east tx skier
08-18-2005, 09:01 PM
Jim, I'm no engine expert. I just know what my manual from MC says. As I mentioned, I've run 87 for extended periods without any catostrphic problems. 93 didn't solve my carb issues. The last time this came up, I resolved the issue for myself sort of like bucky said. 89 is $3 more per tank. I don't run a ton of gallons through my boat per season. Last year, I would've saved a mere $18 running 87 over 89. Since I get some of the gas tax back from the State of Texas ($40 last year), I'm putting some of it toward the sweet gas.

DooSPX
08-19-2005, 10:17 PM
where can we get the K-100?

I want to know as well??

rick s.
08-20-2005, 05:19 AM
I have a '99 LTR and I thought the owners manual recommend 91 or 92 RON. So that's what I use, Chevron mostly.

Engine Nut
08-20-2005, 08:37 AM
We recommend 89 octane fuel for all Indmar engines except for the LQ9 and LS1 which require 93 octane. All but the LQ9 and LS1 should tolerate good, clean, fresh 87 octane. The reason we recommend 89 is that today's fuels degrade pretty fast and over a period of a couple of weeks that 89 octane fuel may be the equivalent of 87 and you will still be ok. But if you start with 87 it may degrade to 85 which is not ok. We recommend that if you buy 87 octane buy it in small enough quantities that you use it up in a weekend and don't let it degrade in your tank for too long of a time.

André
08-20-2005, 08:44 AM
Been running 87 in my 94 TBI for the last 3 years with no problems at all and if there is a power lost,it must be a really small one because i didn't notice it when i did put a tank of 89...100 hrs of use in a short season,gas don't have time to turn bad in my case.

phecksel
08-21-2005, 10:54 AM
We recommend 89 octane fuel for all Indmar engines except for the LQ9 and LS1 which require 93 octane. All but the LQ9 and LS1 should tolerate good, clean, fresh 87 octane. The reason we recommend 89 is that today's fuels degrade pretty fast and over a period of a couple of weeks that 89 octane fuel may be the equivalent of 87 and you will still be ok. But if you start with 87 it may degrade to 85 which is not ok. We recommend that if you buy 87 octane buy it in small enough quantities that you use it up in a weekend and don't let it degrade in your tank for too long of a time.
Accidently bought 87 octane and immediately put it in the boat, almost empty tank. Boat slowed down 3 mph. Next time I filled the tanks, ran premium and regained the 3mph

Jim@BAWS
08-21-2005, 12:52 PM
where can we get the K-100?

From BAWS It is not SOLD in auto parts stores

Jim

PendO
08-21-2005, 12:53 PM
This seems to be an ongoing discussion that never seems to end.
87 is all you need in the good old FORD 351. A tank of 93 every now and then does'nt hurt especially if it is AMOCO or BP WHITE gas. Additives like TECHRON in the Chevron product seems to help. With the price of
gas so damn high why put in the expensive stuff. None of us are running
4 cylinders in our boats. The LQ-9 has a reccomendation for min of 89
but will self adjust to 87. as does the 8.1. We just SOLD a CUSTOM 2006 Prostar 190 with a L-18 in it Mini tower, all red white and blue Special Graphics. AWESOME I will try and post some pictures of this animal.

Additives have had a topic of conversation in the past. I started a thread months ago on a product call K-100. The stuff is AWESOME. Nothing but
postive feedback from customers. Fuel gauges working again. Better performance. The others like STABIL and SEAFOAM can't touch this product.


Jim@BAWS


An L18 in a PS 190 ... WOW, I hope they barefoot:)

Is this the product website? http://www.k100fueltreatment.com/auto.html

bigmac
08-21-2005, 01:21 PM
After poking through my manual the other day I found the below page. I've always run 89 in my boat as I've assumed that the AKI is very similar to the (R+M)/2 method of determining minimum octane ratings.

Would I be correct in assuming that, or would the index determined through the research method, or 93, be what they're calling for to run?

Hopefully this topic will help others out with our era boat as well.

On gasoline pumps, the octane number that's posted is actually the average of the Research Octane Number and the Motor Octane Number, and you should see the method listed there .. (R+M)/2. That is the same thing as the AKI.

Bottom line, the owner's manual you attached is saying that the pump from which you fill your boat should be labeled 89 or higher.

bigmac
08-21-2005, 01:39 PM
If I remember right, reading from my manual, you can use 87 in all current MC motors except for the LQ9....which requires 92.

Can somebody confirm?

My 2004 manual says all current engines want 89 octane except the LQ9 which wants 92 octane.

bigmac
08-21-2005, 01:42 PM
Accidently bought 87 octane and immediately put it in the boat, almost empty tank. Boat slowed down 3 mph. Next time I filled the tanks, ran premium and regained the 3mph

My guess would be the power loss was from detonation, which was picked up by the anti-knock sensor, which in turn retarded your timing to prevent damage.

6ballsisall
08-21-2005, 03:17 PM
Well with all this talk of octane ratings I am going to go top off my tank with 87 and see what happens. I've got 3/4 tank of 89 octane so I bet I wont know the difference.

RobertT
08-21-2005, 03:53 PM
There used to be a octane boost bottle that was sold at AutoZone. Since I fill mostly at the marina....maybe that is a good/cheap way to boost the octane up a little.



Any downside to that?

PendO
08-22-2005, 12:33 AM
There used to be a octane boost bottle that was sold at AutoZone. Since I fill mostly at the marina....maybe that is a good/cheap way to boost the octane up a little.



Any downside to that?

But if the octane boost treats 20 gallons and costs $5 ... you just paid a quarter per gallon, so probably just worth it to get the good stuff at the pump... that said, when it has been a while (over a week) since our boat is run, we usually put in an octane boost.

I'm anxious to try the product rec. by Jim@Baws ... with as much as we pay for our boats, and the pricelessness of free time, I'll feed the boat top shelf, even if it doesn't need it, it is a MASTERCRAFT for god sake;)

PeteS
08-22-2005, 11:18 AM
On gasoline pumps, the octane number that's posted is actually the average of the Research Octane Number and the Motor Octane Number, and you should see the method listed there .. (R+M)/2. That is the same thing as the AKI.

Bottom line, the owner's manual you attached is saying that the pump from which you fill your boat should be labeled 89 or higher.
Great info and posts about the topic. Thanks for answering the question regard pump octane ratings, Big Mac. That's was exactly what I was looking for.

Kevin 89MC
08-22-2005, 11:40 AM
I've run 87 octane in my '89 PS 351 Ford/Indmar for the 9 years I've owned it, and never had an issue. When I pulled my plugs, they were in great shape. I do run a can of either Sea Foam or Stabil in just about every tank, due to the infrequency of use, so that probably does help to keep the octane up. As someone else stated, old gas does lose octane (among other things) so if you run it frequently you might not need to, but I figure it is good insurance for me. I'm not sure I'll ever bother trying a tank of 89 or 91 octane, because mine's carb'd. EFI engines, on the other hand, can (but not always) benefit from higher octane. As someone else mentioned, EFI engines have knock sensors that will detect knock, often caused by too low of octane, and then it automatically retards the timing to prevent the knock. When this happens, power will be reduced somewhat. If the knock sensor/EFI computer can't compensate, that will trigger a check engine light, at least in autos. Not sure about boat engines.
Kevin

RobertT
08-22-2005, 12:50 PM
But if the octane boost treats 20 gallons and costs $5 ... you just paid a quarter per gallon, so probably just worth it to get the good stuff at the pump... that said, when it has been a while (over a week) since our boat is run, we usually put in an octane boost.

I'm anxious to try the product rec. by Jim@Baws ... with as much as we pay for our boats, and the pricelessness of free time, I'll feed the boat top shelf, even if it doesn't need it, it is a MASTERCRAFT for god sake;)

Price might be the same...the issue is that at our marina we have no control over what gas is being pumped...and I can bet its the cheapest they can find.

I think I will grab a couple cans of premium gas and see if I notice a difference.