regular gas???

what kind of gas does everyone use? i have a mobius xlv and i run plus as it says in the manual. but i don't really like paying $.20 extra a gallon. will i hurt anything by just running regular gas?

Yes. Run whatever grade stated in the manual. You don't get any advantage from running a higher octane than necessary, but if you run lower you may cause pinging or knocking. Premature detonation can ruin spark plugs and piston heads and it may idle rough.

I dont think you have to run plus... just the midgrade(89 octane) maybe I am wrong but that is what the indmar recomendations on my supra were!

plus or better.....

According to Skiers Choice 5.7 is 89 and 8.1 is 91 octane

If your motor is fuel injected, there's a 99% chance you can easily get away with 87.

from http://www.indmar.com/engines/engine_detail.cfm?name=ind_57_mpfi

5.7L MPFI (Assault 325)
click to enlarge

Overview

Indmar 5.7L PFI (Assault 325)

Features ETC

(Electronic throttle and cruise)

Don’t look for chromed parts or expensive graphics on this value engine. Do expect nothing less than the perfect power curve day-after-day for solid hole shots through top end.

The newest standard equipment for the 2006 Assault 325 is Indmar’s ETC system --Electronic Throttle Control With Cruise. ETC allows the helm throttle control to electronically “talk” to the engine’s computer at light speed through sealed wires. So, throttle response is now lightning quick and as smooth as a rheostat. Its integrated cruise control is a bonus luxury feature for recreational water-ski and wakeboard families.

Based on the GM Vortec 5700 (5.7L/350 c.i.) block, its field-proven multiport electronic fuel injection (EFI) system is matched to Indmar’s custom designed two-plane intake manifold for reliable, torque-heavy performance. There are more features, too. Such as the free-breathing Vortec heads and gutsy roller cam…all operating under the strict management of a custom calibrated computer control module.

Indmar’s Vortec 5700 MPI is offered by Skier’s Choice (Supra/Moomba) 2006 boat line as the Assault 325. It is backed by Indmar’s unbeatable 3-year limited warranty and award winning customer service. Certified Three Stars Ultra-Low Emission by California Air Resources Board 2006.


General Specs



Displacement: 5.7L / 350 CID

Cylinders: V-8

Bore & Stroke: 4.00 x 3.48

Compression Ratio: 9.4:1 (High-flow Vortec heads)

Fuel System: Multiport electric fuel injection (MPFI)

ECM: Using the exclusive MEFI-V software, it is custom

calibrated by Indmar using GM's ECM (engine computer module) computer.



Ignition: HVS High Voltage Switch Ignition System

Fuel Required: Unleaded, 89-octane minimum



Oil Type: Pennzoil Marine (SAE 15W-40), service SJ/CG4



Max. RPM: 5,000

Warranty: Indmar’s exclusive 3-year limited warranty includes fuel and electrical systems.}

(Message edited by gmarkham1 on May 11, 2006)

plus is 89 regular is 87 so i guess i gotta run 89

guess I should have asked which engine, but that is the 5.7,

yeah i have the indmar assault 5.7 325hp

like i said on wednesday i run reg. no pin. or knock and i have the 340 power and my dealer and Diggs say reg. is ok

I run regualr in my SSV. no problems

the modern EFI engines have an anti-knock sensor which compensates for imperfect combustion you get with regular gas. This is according to "Click & Clack - the Tappett brothers" on PBS. They say disregard the manufacturers recommendation for higher octane, and if it runs smoothly, you're OK.

I run regular in mine and have no knocks or pings.

I run regular in my 340...no pinging, knocking or recognizable hinderance in performance.

The only gas I don't put in the boat is from on the water gas stations. Both times I did that last year I had to replace the fuel filter.

(Message edited by ripr on May 11, 2006)

Rich is right. However, the computer may adjust out a little performance to compensate. Whether you notice or it is important to you, that is a personal decision. Indmar uses 86 octane to develop the software on the motor. Above 89 octane, you are wasting your money. Personally, I use regular in my MCX without a problem or performance problem.

I do, however, suggest that you run some Chevron Techron through the motor every 5th fillup or so. It will keep the fuel system and cylinder heads much cleaner and trouble free.

FYI - there is no difference in "brands" of gasoline. All have to meet the same standard for pipeline transportation. Avoid a station that has just taken delivery of new fuel - it stirrs up the sediment in the bottom of the tank and the filters on the pump are pretty coarse - if they are actually installed.

thanks Karl, thats good info to know. if you feel safe running 87 in your MCX then i think 87 will be more than fine in my motor

If it don't ping, use it!

http://www.usatoday.com/money/autos/2003-07-30-premiumgas_x.htm

Why use premium gas when regular will do?

USA TODAY Says Premium Gas is a Fraud

Automotive experts state that high-octane gas is needed by only supercharged engines.

I got a performance tune for my boat. I burn 4 gallons per hour when running 91+ octane. Anything less and I get detonation.

just think about filling up on the lake or river... no such thing as anything better than 87 on the water. i have always run 87 and never had issues....

If the knock sensor were to fail then you could destroy a piston(s) with the low octane

Diggs, on the Delta at H&H marina, they only have 89 and 91 octane.

We have a phillips66 in town that has 87 & 89 for the same price all the time and it is one of the cheapest places in town. I have an old boat without any kind of computer and the manuel says run only leaded 92 octane gas. Well since it is a little difficult to find leaded gas I run unleaded 89 and have not ever had any problems. Although the few times I have put 92 in it, it does run a little better.

I started using regular gas this season after hearing from a few friends who have been using it in theirs. However, over the past 3-4 months, since I often go a week or two in-between riding, I have been throwing in some Sta-Bil as well. I've been usining the small bottle (treats 20 gallons) with each fill up (my tank holds 40 gallons). I have to say that my boat has never ran better! It sounds better, it accelerates better.

I had read somewhere that fuel starts to deteriorate after two weeks. I have also read that higher the octane, the longer the gas will stay fresh. Whether any of that is true or not, I don't know for sure. I do know, however, that since I have been using Sta-Bil with each fill up my boat has been running great!

As the weather strats getting warmer I will probably start to use less of the Sta-Bil as I start to use the boat more often. But, anytime that you know that you probably won't get out in your boat for two weeks or more, dropping in some Sta-Bil probably isn't a bad idea.

The Mercruiser in my Centurion says run 87 octane, nice to save $.15/gallon - compared to the Indmar in previous boat.

Marinas in the area only have 89 or 91 octane.

FYI - You loose 1 octane rating a month.

My father used to work for Dresser or what is now Halliburton. They manufactured gas pumps. He says that 87 is fine for just about any regular vehicles that there is no need to run the higher octanes unless you are talking about a special performance car etc. I suppose some boats can be considered performance vehicles..i run 87 in my Centurion and have never had a problem. same with my jeep and even in my crotch rocket..when i had it..no problems. i think its mostly a marketing ploy....just my .02$

i have an 06' x-stare with the MCX engine and it say to use 89 so i use 89

I had a buddy who's dad is a VP for Shell oil and he is a car collector, has some awesome Vettes, he says that plus and super or premium is a joke. He puts regular in all his vehicles. By the way we know that by the price of gas how he can be a car collector. Someone must be getting rich from this.

dg

My old muscle car states on the core support to use 91 or higher octane, it was ok when the price was cheap but when the price got out of hand I just used regular and it ran just fine, I am using regular in my boat also but I will put some kind of additive in once in a while,

What make your body perform better:
Bush light
Coors light or
Bud light????

Bud Heavy...

Found this on another site, makes sense to me...

After much discussion, it has been found that 87 octane can be run in most of the engines, however it will retard the timing and decrease performance.


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.

I'm running either 100 octane propane or 95 octane unleaded gasoline depending on which way I flick the switch (its dual fuel).

Gotta love the UK prices for fuel. It may be 4 x times the cost of your fuel but at least its not that watered down low octane stuff you have to use. Almost feel sorry for you - NOT!

I run 89 because it's what's recomended for my MCX. I'm also not going to complain about the extra $3.50 that it costs to fill my boat. I mean really what does $3.50 mean to you?

Maybe someone is getting over on me, but I'm OK with that for the peace of mind. I'll run regular in a pinch if thats all a marina has, but more of the places that I've run into on the water have 89 as their base gas.

My malibu had a Merc Black Scorp (5.7 first gen.), it ran like trash on anything but 91.

I run 87 in my 2001 malibu response with 800hrs. I havent noticed a difference. I was told by a guy that works with engines that premium and plus is a joke unless you are driving a high permformance vehicle such as a supercharged or turbo charged engine.

what Bryan Lionel said makes a lot of sense. Since I burn all of the gas I buy within 2 days, I dont think I will be buying anything but 87 this summer.

naw, due to water in the fuel or? Ive had that problem with on the water stations too....extra 50 cents a gallon for crappy gas sucks.

BTW, the reason cars "recommend" higher octane is because they must since they SMOG/PERF test them with the higher octane. Testing the cars with the higher octane gives them slightly better SMOG/PERF results (certification/marketing numbers). Meanwhile, most MOST MODERN cars will run fine on the lower octane. Thats the truth on cars. Try the lower octane -- if it pings, add octane booster and forever run the higher octane -- if it does not ping, forever run the lower octane.

(Message edited by greatdane on May 13, 2006)

I just bought a used Moomba with an Indmar 330 HP fuel injected engine (690 hrs). The guy that I bought it from ran 87 in it and it seems to be fine. Should I switch to 89 or stay with the 87?

my buddy with a centurion runs 89 in his mercruiser and wont put 87 in it... hes rich so I guess he doesnt care, my tige the manual says 87 Im pretty sure for the mercruiser 350mpi... 500+ hrs at only 87 and it still runs great, I dont fill up on the lake tho... dont trust the sketchy peoples tanks...

ive been running 87 in boat for last 2 outtings, and we had the boat loaded and i didn't notice any problems running 87