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ed bullock
05-11-2002, 10:43 PM
i can only get 91 octane fuel where i live do i buy race fuel or octane boost to get over 94 octane where i need to be what is the best way to go

Skaterfast
05-12-2002, 07:35 PM
I mix 1/2 super unleaded and 1/2 Av gas.Any small airport will have it and will let you pull your boat in.Av gas has a real good record in outboards.

HavasuDreamin'
05-13-2002, 06:18 AM
What is the compression on your motor?

ed bullock
05-13-2002, 01:19 PM
Originally posted by HavasuDreamin':
What is the compression on your motor?
it is under 130 psi

HavasuDreamin'
05-13-2002, 04:57 PM
No need for av-gas, just run 91 consistantly, no 89. Stock Mercury (at least 2.4 Litre Carb Motors) compression is 125 psi, and my ran fine on 92 for years. Not until you get up around 140 or so would I consider mixing 50/50 (av-gas & 91). However, this is not to say you couldn't get some bad gas and do some damage, but I never had any problems. Good Luck

Capitalist
05-14-2002, 11:19 AM
You can run up to and over 140 psi on 91 oct, 130 you can even get away with 87 if you have to. AV FUEL IS THE WORST THING YOU CAN DO TO AND OUTBOARD----NEVER EVER RUN IT. Consider this, AV fuel was designed for an air cooled 1000 foot per min (piston speed)4 cycle that cannot have a spark plug foul. The fuel has a chemical in it that is designed to disperse oil (and adding a lot of oil will not stop this). Consider that the motor in question is a liquid cooled, 3-4000 foot per min motor that require oil in the combustion chamber to run.
If you have ever heard the term "AV runs dry" that is why. It will cut your motor life in less than half.
ET

Screaming Pete
05-15-2002, 11:09 AM
H/D, I have a 300promax stock and it calls for 92 octane and az. at martinezonly has 91 and i will run all the 92 i truck in and was going to add av gas to bump the octane but it sounds like i should run maybe a trick addive instead what do you think . S/P

Skaterfast
05-15-2002, 11:48 AM
I don't care what the compresion is,all you guys with outboards should run 93 octane or better.The next time you go into your local outboard shop and see an outboard being rebuilt ask them what happened?Fiftey percent of the time it's piston failure due to bad gas.I've logged thousands of hours on all different kinds of outboards and have never had fuel problems.I've been running
50-50 for 10 years now.If you have 40 gallons of fuel in your boat and av gas is on average .40 more a gallon that's only 8 bucks a tank.One motor rebuild can be 4k.Eight bucks or 4k,hhmmm.Do yourself a favor,spend the 8 bucks now.

Capitalist
05-16-2002, 05:20 AM
If you are paying 4 k for a motor rebuild, I will do them all for you.
The piston failures are not anything to do with detonation, they are the ring locating pin failures. This is caused from poor design and high rpm. If for even a few seconds you detonate an outboard you WILL have a hole in a piston.
AV will do a lot more harm than good.
I have been doing this for 22years and have a few world championships to qualify that with.
Anything und 130 can run on 87, under 140 on 89, and under 150 on 91. Timing and jetting are key.
ET

Skaterfast
05-16-2002, 08:14 AM
Capitalist,you have not convinced me yet.I talked with Lake X yesterday and they say everything you are saying about psi and octane.However they had nothing bad to say about av gas in outboard motors.With the amount of av gas I have ran through I have never had a problem.You do bring up some interesting points though and maybe I need to do a little more investigating.

Capitalist
05-16-2002, 10:54 AM
Merc wants to sell parts. The resaon the pistons fall apart is becase merc won't spring the extra 5 dollers per motor (that is not a typo)for pistons that a 10 times as good. Merc is the king if engeneered obselecence....Mr. Kiekhafer is rolling in his grave.
I should mention that you will not blow up a motor on AV, just that you will wear it out faster ( a lot faster ). And that the extra expnse is not warranted (fuel and rebuild).
ET

HavasuDreamin'
05-16-2002, 11:32 AM
I run 155 PSI in my merc. I run Av-gas straight, no mix, and have been doing this for more than 5-years. No problems. Motor still has excellent compression. I have been in very reputable shops before (Dick Sherrer Marine & Lakeland Marine) and seen pistons with holes in them, melted pistons, etc. In each case, the engine builder said........."look what bad gas can do, make sure to run good gas and synthetic lube."
I don't understand your point that av-gas will harm my motor (lower life expectancy). I have more than 100 hours on my 155 PSI Merc running nothing but Av-gas. Top RPM is in the 7200 - 7400 range. I would think that if Av-Gas was going to wear it out sooner, it would have done so by now. By the way, do a search and check out what the blower motor guys say. This topic has been covered multiple times. Most of the Blower motor guys run av-gas as well. Few to none have problems.

Capitalist
05-21-2002, 12:12 PM
100hrs is not a lot of time, compression does not tell you the condition of your rings, only a Leakdown test will tell you that. Your motor is a 2 cycle, not a blown 4 cycle. Consider that one requires oil in the fuel to run and the other doesn't........... two very different animals please don't make the comparison.
ET

ed bullock
05-21-2002, 08:41 PM
okay i have heard alot of input on this suject i talked to a merc rep he told me not to use premium fuel because it sits and gets old. he says it dosent have the additives that mid grade does. so what about buying mid grade wich is 87 octane where i live and mixing it with a fuel that vp makes called c-12 made at 108 octane leaded made for marine use it is expensive but is it worth going the extra mile and using a synthetic oil.i have learned alot from every one here and want to say thank you fot all the info.

Capitalist
05-22-2002, 05:44 AM
Now you are talking.
Though, the C-12 (that is what I run but at 100% with 210psi compression)will loose it's octane very quickly if left out.
A little trick is to put a valve in the fuel tank vent and close it when you store the boat.
Use, Penzoil 100%, Klotz, or the best in the business Alisyn for motor oil.
ET

ed bullock
05-22-2002, 03:40 PM
does everyone agree that c-12 is a quality fuel? it is built for 2 strokes the price is high but if it is able to prolong the life of your power head it may be worth the money. av-gas guys have you used this product ? can it be mixed half and half and still have the edge over av-gas ? this seems to be a hot topic that every one can use information on .

Tom Brown
05-22-2002, 08:39 PM
Ed, what engine do you have? Static compression is not the only factor in determining the type of fuel an engine requires.
I run premium non-lead in my stock 1989 XR-4 and it does just fine. My static compression is 130 psi.
My $0.02
Tom Brown

ed bullock
05-23-2002, 04:53 AM
tim i have 1997 2.5 260

Capitalist
05-23-2002, 05:08 AM
Ed if that motor is stock, run 91 oct or better and forget all the above. That motor will even run on 89 oct if you have to but, I would not use it as daily fuel.
And yes C-12 is one of the best fuels for a 2 cycle C-44 is better, and Sunoco Purple (CAM 2) is also very good.
ET

gregg canavan
05-23-2002, 04:35 PM
gee guys, I run mid grade, 89 octane for a while now, I havent had any trouble. I'd like to spring for the 93 octane but I hold 200 gals and we'll go through 300 gals in a weekend...the extra money really adds up. Not to mention the oil at 15.00 a gallon
89 octane is ok, isn't it?

ed bullock
05-23-2002, 05:38 PM
i have burned pistons in my johnson 2.6 gt and my bridge port running 91 octane maybe i am having other problems than fuel but when i started running 91 octane that is when all my problems started . am i looking in the wrong area ? all i want to do is cover my bases if running av gas or c-12 or mixing either half and half is over kill but it gives me piece of mind and my troubles go away i can live with that. i have had out boards for 18 years and never had this problem until now. i could be barking up the wrong tree it could be something else but i think i will do av gas or c-12 any way and if that dosent work then i will have to just enjoy high performance in hot boat magazine that is if i can afford the supscpription after all my repairs. thank every one for all of your help truly you all have helped me with this problem.

snappertapper
05-24-2002, 04:44 AM
i dont know much about fuel but i seem to have pretty good luck running 89 mid grade haven had fuel related problem yet

HavasuDreamin'
05-24-2002, 06:28 AM
Ed, mix 50/50 91 octane and either av-gas or race fuel. You will be fine!

Skaterfast
05-25-2002, 02:29 PM
I can't remember ever purchasing gas at a marina or from a dock.This eliminates the chance of water in the gas.Just a little extra insurance.

ed bullock
05-28-2002, 02:52 PM
i have decided to use redline 2 stroke oil is this a good choice ? however i was told not to use it for break-in the sales man told me to use yama lube the motor is a 97 merc 260 hp 2.5 rebuild. do i still mix redline at 32 to 1 i have heard synthetics you use less oil ? i have also decided to mix pump with higher octane fuel half and half. as soon as my gaskets come in i will be ready to try it out thanks guys.

Skaterfast
05-30-2002, 03:00 PM
Long story short:Two guys bought 2 Stoker boats powered by your exact motor and took delivery 2 weeks apart.First guy wanted to save money so he ran Klotz oil.Second guy (me) was smart and bought a barrel of the high performance oil at a greatly reduced(about 1/2) price.He got lucky because when it blew up after 15 hours the shop who performed the waranty work didn't do much investigating and put a new power head on.He ran the Merc oil from then on.I would not change oils either,stick with what ever you break it in on.In my opinion it's not worth saving 100 or $200 a year,if in fact that's why you are not running Merc oil.Just my opinion.

ed bullock
05-30-2002, 05:52 PM
thanks for the reply the reason i was going to use red line was not because of price but it is on the shelf at my local merc dealer . theystock premium blend merc oil but i believe there is a step up from that isnt there ? they dont know what i am talking about when i ask for the race oil. if red line is not acceptable then by no means will i use it i live in salt lake where they think a 225 optimax is high performance. i took my boatin for a new water pump told them to ckeck the motor for loss of power i pick it up he told me it was fine i go to the lake same loss of power go home compression ckeck dead hole. thats what kind of people i deal with you guys are my gods when it comes to this .

HavasuDreamin'
05-31-2002, 05:48 AM
Klotz makes an excellent synthetic oil. You ever wonder why you see so many formula 1 boats with big Klotz stickers on the back? My motor guru who put together my motor swears by it. He is an ex-formula 1 racer. Personally, I have ran Klotz for 2 years now without any problems. I have also had excellent luck with Merc Synthetic. Ed, what you want is a synthetic lubricant. They are superior to the TCW-3, so whatever you brand you get, get a synthetic. I mix 32:1 because I hot rod around a lot. Some will say you can get away with 40:1, but why chance it. I always error on the conservative side. That equals more boating and less headaches.
You can get ahold of Klotz and order oil through the mail. They are located in Ft. Wayne, IN. A case is about $145 with shipping (case = 4 gallons). Web address is www.klotzlube.com (http://www.klotzlube.com)
You can also call them at 800-242-0489.
Good Luck and safe boating. http://free.***boat.net/ubb/smile.gif

ed bullock
05-31-2002, 02:48 PM
so i get synthetic lube do i use it for break in the red line container says only use it if at 80 percent load what does that mean ? bottom line is i am a week away from ignition and want to have it dialed the dork at the boat shop told me to use yamalube for break in can i use any synthetic and be safe ? if i break in with something else i will have to switch back to synthetic wich is not good right ?

ed bullock
06-01-2002, 04:15 AM
if you mix 91 octane with 108 octane half and half would that bring the octane to 99 ?

Skaterfast
06-04-2002, 01:14 PM
99.5 to be exact.

22TWIN
06-08-2002, 01:54 PM
I live in Phoenix where only 91 octane is available.My power is 2x'01 2.5 EFI sport mercury outboards (280 hp )Is this fuel going to cause engine problems? Mercs website recommends 92 octane.

ed bullock
06-08-2002, 02:12 PM
i dont know if it will. i ran 91 in two of my motors and they failed. i went to mid grade fuel 88 and c-12 vp racing fuel 108.i mix half and half to reach 96. i only have 20 minutes on my power head so i dont know if it helps. but a little insurance dosent hurt. i have been told by some respectible recources one of them a merc rep that the 91 premium fuel is not a good quality fuel.it does not have the additives that mid grade does plus it dosent sell fast and sits in the tank and gets stale. the c-12 burns cooler so that has to be a plus. your oil is important run synthetic i have chosen merc race oil. out in the west you can only get 91 from what i hear. i am in salt lake so i am in the same situation as you. good luck

Skaterfast
06-10-2002, 04:38 PM
Originally posted by 22TWIN:
I live in Phoenix where only 91 octane is available.My power is 2x'01 2.5 EFI sport mercury outboards (280 hp )Is this fuel going to cause engine problems? Mercs website recommends 92 octane.
It's not if ,but when will your 280hp blow up on 91 octane.

22TWIN
06-11-2002, 07:35 AM
FYI. I just got off the phone with mercury racing. His thoughts were that 91 octane alone would not cause a problem. The problems occur when all things are not optimal;i.e.weak waterpump,old fuel,fuel with moisture in it,etc.He went on to say that 91 starts to loose octane after 15 days so to get your fuel from a busy station that turns the fuel quick.Also,if your not going to use your boat for more than two weeks to put in a stabilizer.His recommendation to me was to obtain either 99 to 100 octane nav gas or cam 2 racing fuel and mix 10 to 1 with the 91 octane and I won't have problems.So,next question.Where is the best source for nav gas or cam 2 fuel?

22TWIN
06-11-2002, 07:41 AM
Sorry,av gas not nav gas

HavasuDreamin'
06-11-2002, 11:15 AM
Originally posted by 22TWIN:
So,next question.Where is the best source for av gas or cam 2 fuel?
Avgas.....if you go to Havasu you can get it at the pump. If you don't, then try your local airports. You will have to put a container in the back of your truck, they won't fill up a boat. Do not tell them that you are putting the gas in a boat. Tell them you have a small plane or a sea plane, etc. I went to my local airport and said I had a boat. The lady said, now...if you were to tell me that you had a plane and you brought in a gas can http://free.***boat.net/ubb/wink.gif I could help you out. I rolled down there the next day with my 30 gallon gas caddy and filled up. You want 100LL fuel. Do not go with 87LL or 140LL. Another option is to call your local hot rod shops and see if they know of any stations in town that sell race fuel or av gas. Good Luck!

Skaterfast
06-11-2002, 11:55 AM
Hhmmmm?I wonder why Merc manuals say 92 octane or better for the High Performance motors?

ZSARGO
06-11-2002, 12:02 PM
IN MY OPINION IF MERCURY ADVERTISED THE FACT THAT YOU HAD TO RUN AV GAS OR 100+ OCTANE FUEL TO KEEP THE MOTOR TOGETHER THEY MAY SEE A SLIGHT DROP IN SALES. SO 92 MAY WORK, BUT IT'S NOT THE BEST FUEL TO RUN IN YOUR MOTOR. I RUN STRAIGHT AV WITH A 32:1 RATIO ( MERCURY HIGH PERFORMANCE OIL) AT 6500-7500 ALL DAY LONG AND THE BOAT HASN'T SKIPPED A BEAT.

Skaterfast
06-13-2002, 04:33 PM
Mercury will tell you ,"the reason you want to run 32:1 and 92 or better on the octane is that we(Mercury) have never had motor problems due to oil or gas failures".They will also tell you they have "never tried any other oils because why should they,the hp oil works perfect".

tunnelvision
06-14-2002, 08:17 PM
hi gang
recently acquired a small tunnel outboard, more on that later...gonna need some advice!
california...max 91 octane at pump, some 76 stations sell the 100 octane at $4 plus a gallon.
saw a deal about the fitch "catalyst" drop-in...appears to be more legit than the other miracle fuel additive solutions. no info on applicability for 2-strokes, however, yet.
here is another way...Toulene or Xylene mixes. used successfully, no holes, no detonation, no problems if the mixture is followed per formula, but hell, if these motors are running ok on straight av, this is gonna be lightweight stuff...
TOULENE...available at paint stores, etc.
R+M/2...114
Cost...$3 gal
Mixtures with 92 Octane Premium
10%...94.2 Octane
20%...96.4 Octane
30%...98.6 Octane
XYLENE...same paint stores, etc.
R+M/2...117
Cost...$4 gal
Mixtures with 92 Octane Premium
10%...94.5 Octane
20%...97.0 Octane
30%...99.5 Octane
There are also formulas for Methyl-tertiary-butyl-ether (MTBE), Methanol, Ethanol and Isopropyl Alcohol (rubbing alcohol) and Tertiary Butyl Alcohol, but i think i will wait to comment on these alternatives until any roasting i receive regarding Toulene and Xylene subsides...
these mixtures are used successfully in 4 strokes (car engines) fuels to raise octanes, but how or if the applicability to 2 stroke outboards goes is a mystery to me, i am only bringing this up for discussion and not recommending it for 2 strokes, but if all we are doing is trying to raise the octane of our fuels, here is one possible way...
if you don't like it, don't beat up on me too bad, its my first post dammit!
mike