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FUEL- What is the best grade to use???

5K views 14 replies 10 participants last post by  RC51PROUND 
#1 ·
I have read threads , recently on the forum- with concerns of exhaust changes, airbox mods,etc. Of making more HP.
Now going back to RougeRC51 always for a reference - Fuel .. We all know that the RC-51 is a low compression engine.. and logically using 87 oct. fuels are the way to go... Dyno run charts showing the most output with this fuel..
Yet is the lowend fuel as clean as the upper grade ? (91octane)
Is there a recommend fuel injection additive/cleaner -- other than SeaFoam.. Which I have concerns of use?

Input on the suject??
 
#2 ·
I always run 93oct pump gas.

I use a few shots of seafoam to a full tank, once a oil change and then run that tank out with in a day or 2. Also I have useLucas Fuel treatment Over all I cant really tell if its doing and good or harm.

Now after reading the write up on Rouge, I would really like to know more about 87oct for the RC.

James
 
#3 ·
I was using 100 RON fuel since I got my RC back in 2008.
At some point, mostly due to cost, I changed to 95 RON fuel which is the most common here in Greece.
I can't say I noticed any dramatic difference on the throttle though. Just the big one in my wallet.
Lately I was considering, since I don't have the OEM slip ons on with the catalyst converter inside them, to change the fuel to Super LRP which is the one with the lead additives in.
Would that make the engine to run in lower combustion chamber temp.?
I know that in 2 stroke engines it does. The unleaded fuel causes high temps on the piston's head and on the valve's seats especially the exhaust's ones.
 
#7 · (Edited)
I tried Stabil Marine to store my jetski this last winter. Normally I drain the fuel lines and carb, (and risk drying out the seals and O-rings), so this year I just used the storage mixture ratio and left the gas in it. It sat for about 6 months on the battery tender and when I fired it up about a week ago, I couldn't believe it fired on the first spin and ran great. I'm a believer! I think the Stabil Marine is effective at neutralizing that bad bad bad ethanol.
Want to do a little more research, but I'm thinking of using it for the RC51 if I'm not riding it for more than a couple weeks.
 
#8 ·
This is from marine company, Mercury, but still applicable. From https://www.mercurymarine.com/en/us/faq/

Question: Is there a simple solution to water condensation in the tank as a result of ethanol?

Answer: It is best to maintain a full tank of fuel when the engine is not in use. This will reduce the void space above the fuel and will reduce the flow of air in and out of the tank with changes in temperature. This will reduce condensation on the internal walls of the tank and will limit exposure of the ethanol in the fuel to humidity and condensation.​

Question: Are there any additives that can allow the phase-separated mixture to remix when added to the fuel tank?

Answer: No, the only way to avoid further problems is to remove the water, dispose of the depleted fuel, clean the tank and start with a fresh, dry load of fuel.​

Question: Is an additive available that can prevent phase separation?

Answer: There is no practical additive that can prevent phase separation from occurring. The only practical solution is to keep water from accumulating in the tank in the first place.​

Question: Are older fuel lines prone to failure from ethanol-based fuels? What about gaskets?

Answer: During the 1980s, many rubber components for use in fuel systems were developed to withstand exposure to fuels containing ethanol. If rubber components in a fuel system are suspected to be of this vintage or older it may be advisable to replace them with newer ethanol-safe components before using fuels containing ethanol. Check with the manufacturer for advice or frequently inspect these fuel-system components for signs of swelling or deterioration and replace if problems are noted.​

Question: What should be done when storing boats with ethanol-blended fuels for extended periods?

Answer: Follow the instructions for normal storage preparation found in the Operation, Maintenance & Warranty manual. When preparing to store a boat for extended periods of two months or more, it is best to completely remove all fuel from the tank. If it is difficult or not possible to remove the fuel, maintaining a full tank of fuel with a fuel stabilizer added to provide fuel stability and corrosion protection is recommended. It is best to add the stabilizer and fuel treatment to the tank at the recommended dosage, run the engine for 10 minutes to allow the system to be cleaned, shut off the fuel valve to interrupt the fuel supply and allow the engine to run until it stops, and top off the tank until it’s full to reduce the amount of exchange with the air that might bring in condensation. Do not cap the tank vent and do not fill with fuel to the point of overflowing. Some extra space should be maintained in the tank to allow for expansion and contraction of the fuel with temperature changes. A partially full tank is not recommended because the void space above the fuel allows air movement that can bring in water through condensation as the air temperature moves up and down. This condensation could potentially become a problem. Mercury Marine Quickstor can help maintain fuel systems in storage. Quickstor contains oxidation inhibitors to reduce oxidation and gum formation, metal-chelating agents to protect metal components from corrosion, and water-absorbing agents to reduce the presence of free water.​

Question: What should be done when storing boats with ethanol-blended fuels for extended periods?

Answer: Follow the instructions for normal storage preparation found in the Operation, Maintenance & Warranty manual. When preparing to store a boat for extended periods of two months or more, it is best to completely remove all fuel from the tank. If it is difficult or not possible to remove the fuel, maintaining a full tank of fuel with a fuel stabilizer added to provide fuel stability and corrosion protection is recommended. It is best to add the stabilizer and fuel treatment to the tank at the recommended dosage, run the engine for 10 minutes to allow the system to be cleaned, shut off the fuel valve to interrupt the fuel supply and allow the engine to run until it stops, and top off the tank until it’s full to reduce the amount of exchange with the air that might bring in condensation. Do not cap the tank vent and do not fill with fuel to the point of overflowing. Some extra space should be maintained in the tank to allow for expansion and contraction of the fuel with temperature changes. A partially full tank is not recommended because the void space above the fuel allows air movement that can bring in water through condensation as the air temperature moves up and down. This condensation could potentially become a problem. Mercury Marine Quickstor can help maintain fuel systems in storage. It contains oxidation inhibitors to reduce oxidation and gum formation, metal-chelating agents to protect metal components from corrosion, water-absorbing agents to reduce the presence of free water, and dispersants to help suspend and disperse debris. When placing the boat back in service, be sure to reopen the fuel valve to the engine.​

Question: Can ethanol-blended fuels affect the performance of traditional carbureted two-stroke outboards?

Answer: Two-stroke outboards should experience little or no decrease in performance due to gasoline fuels containing up to 10-percent ethanol when operated according to Mercury's standard recommendations. When gasoline with ethanol is used for the first time after a fuel changeover from MTBE, the tank must be completely free of water prior to introduction of gasoline with ethanol. Otherwise, phase separation could occur that could cause filter plugging or damage to the engine. (It is probably better for a boat owner to fill the fuel tanks with ethanol fuel for the first time when the tank is low on fuel, but that is not critical. There should be no difficulties if the tank is clean and free from water. If the tank is not free from water, a partial load of fuel will more easily phase separate because with less ethanol in place it takes less water to cause phase separation. The important thing for boaters to concern themselves with is the presence of water in their tanks.) If an engine is a 1990 or older model, frequent inspections of all fuel-system components are advised to identify any signs of leakage, softening, hardening, swelling or corrosion. If any sign of leakage or deterioration is observed, replacement of the affected components is required before further operation.​
 
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