How Much Gas ??

[BobRae99]

Hi All,

So, a bit of an exciting day coming - my new 2016 Cobalt 210 will be delivered to my marina tomorrow afternoon by the dealer. It holds 40 gallons of gas. I'm not sure whether I should have it filled up completely before launch (less expensive at a local gas station than the marina) or just have it delivered with 1/2 tank and add a half a tank as needed? I've read that you should just carry enough fuel to meet your needs rather than filling the tank completely unless of course, you are heading out on a longer trip.

My engine run times will likely be around 1 - 1.5 hours per outing and within about 4 - 5 miles from the marina. Is it wasteful to haul around the weight of the extra fuel when I won't need it, or should I just fill it each time?

Power is a Volvo Penta V6/280. Should I be filling with regular or premium?

Thanks,

Bob

[Bamabonners]

I'd fill it up where it's cheaper and call it good. Gas gauges on boats are never that accurate, so I usually fill up at half a tank.

[cmattj]

Keep it full as boats are vented systems and moisture can build with sitting.( especially with ethanol). Always keep micro towels with spray wax as boats love to burp fuel from the vents when full.

87 octane is perfect. As higher octane fuel is actually slower burning and won't improve performance. If anything it will hinder it( that's another topic)

Congrats!! Exciting!! And need pics!! You may have told us before but... It's Red right??

[BobRae99]

Keep it full as boats are vented systems and moisture can build with sitting.( especially with ethanol). Always keep micro towels with spray wax as boats love to burp fuel from the vents when full.

87 octane is perfect. As higher octane fuel is actually slower burning and won't improve performance. If anything it will hinder it( that's another topic)

Congrats!! Exciting!! And need pics!! You may have told us before but... It's Red right??

Actually is Ebony with a Citrin (yellow) bootstripe. I had a Cobalt Bimini (ebony) added by the local dealer. It sits on a Shorelander dual axle trailer with hydraulic (surge) single axle disc brakes. I bought the least expensive trailer I could as it will only travel about 130 miles each year on flat land and will also be used to store the boat.

As to the fuel, it will have to be premium as that is the only fuel (aside from diesel) that the marina provides.

I think I've posted some pictures of it as it sat at the factory, but I'll try and take a few at the dock tomorrow.

[cmattj]

Yes.. I recall. Awesome Combo! looking forward to seeing more

[BobRae99]

Hi cmattj,

Just by way of follow up, I accessed Volvo support by entering my engine's serial number and found the following on page 103 re: fuel requirements. Based on what I am reading, I wouldn't think that higher octane fuel would hinder performance - the manufacturer seems to be saying the opposite.

Lots for me to learn.

Bob

PS Pictures here: viewtopic.php?f=28&t=894

P103:

"NOTICE! Engine damage resulting from the use of
lower octane gasoline (below 87 AKI or 90 RON) is
considered misuse of the engine and is not covered by
the warranty.

All Volvo Penta gasoline engines are engineered to
operate on AKI 87 (RON 90) octane fuel. Mid-grade
and premium fuels contain injector cleaners and other
additives that protect the fuel system and provide
improved performance. EFI engines may obtain an
increase in power from higher octane fuels."

[thunder550]

Octane is a measure of resistance to ignition. Higher octane means the fuel is harder to burn. This is necessary in higher compression or forced induction engines where more air is being compressed into smaller spaces, causing the air/fuel mixture to heat up as it's compressed. If it heats up too much, it can ignite while the piston is still on it's way up, causing preignition or detonation (knock) and possible engine failure. It can also be necessary in engines that run a lot of timing advance, flame front from the air/fuel mixture ignition can advance too fast with lower octane fuels and cause the same problems. Higher octane fuels are harder to burn and are necessary in these situations because they are more resistant to burning, and won't preignite or detonate/knock as easily. If the engine and calibration are designed for 87, higher octane won't help it and will just make your wallet lighter. It just depends on the engine and ECM calibration. Some will work on either, they have "high octane" timing maps that will make more power as long as they don't detect knock. Once they detect knock, they will revert to the low octane timing maps to avoid damage, and make less power as a result.

Additives and cleaners are another thing, I'm not familiar enough with them to offer an opinion on that.

[cmattj]

Yes it's actually due to systems sensing ping and knock that the will reduce timing and or guardian mode should the timing adjustment not be enough.. hopefully you don't have fuel below 87??

If a combustion engine doesn't ping or detonate on 87 octane increasing the octane ( slower burning to suppress ping or knock) there is no increase in power.

Just saw T550 .. thanks pal. That's why I said it's a whole other topic.

MFG would obviously want slower burning fuel for protection

[BobRae99]

Thanks, guys.

Regardless of the octane "controversy" and claimed reasons why manufacturers might advise one thing or the other, as an owner of a new Volvo Penta product, I somehow feel compelled to follow the manufacturer's direction in matters such as the break-in, fuel rating, oil change intervals and other maintenance. If this was a lawnmower engine, I'd be more willing to go it on my own (so to speak).

From what I read, Volvo Penta claims improved performance with higher octane fuels. Based on what I know about knock sensors and pre-ignition, I can only assume that a combination of factors such as air temperature, boat loading and drag conditions (skiers?), the engine might be forced to protect itself from pre-ignition, despite being in the compression range where under lighter loads, the engine would not be subject to pre-ignition. So while an engine might be designed to operate with 87 octane fuel, there might be cases where the timing has to be adjusted to avoid pre-ignition, but if it was being supplied with higher octane fuel, it might not need to retard timing and depower to avoid knock. I suspect that is the performance gain Volvo Penta is talking about.

In any event, the only fuel my marina has is premium (91 I believe), so that is what will be going in the tank and according to VP, that is fine.

Thanks for weigh in.

[AsLan7]

Thanks, guys.

Regardless of the octane "controversy" and claimed reasons why manufacturers might advise one thing or the other, as an owner of a new Volvo Penta product, I somehow feel compelled to follow the manufacturer's direction in matters such as the break-in, fuel rating, oil change intervals and other maintenance. If this was a lawnmower engine, I'd be more willing to go it on my own (so to speak).

From what I read, Volvo Penta claims improved performance with higher octane fuels. Based on what I know about knock sensors and pre-ignition, I can only assume that a combination of factors such as air temperature, boat loading and drag conditions (skiers?), the engine might be forced to protect itself from pre-ignition, despite being in the compression range where under lighter loads, the engine would not be subject to pre-ignition. So while an engine might be designed to operate with 87 octane fuel, there might be cases where the timing has to be adjusted to avoid pre-ignition, but if it was being supplied with higher octane fuel, it might not need to retard timing and depower to avoid knock. I suspect that is the performance gain Volvo Penta is talking about.

In any event, the only fuel my marina has is premium (91 I believe), so that is what will be going in the tank and according to VP, that is fine.

Thanks for weigh in.

You'll be fine BR99.
I run 92 octane in my 496 MAG HO. Just like Volvo, the Merc manual recommends 87 as a MINIMUM. 92 as acceptable (page 39 of Merc manual http://www.boatfix.com/merc/owner/gas/86302010.pdf.)...Bigger issue is if you ran leaded gas or dropped below 87 like some third world countries and cheaper states.

Enjoy.

[Big Block Power]

I can get 87 and 93 noneth. Gas. Can't notice a ounce of performance diff between them. 87 is almost a buck per gal cheaper but it's a bit out of my way.

[AsLan7]

Btw, one other thing. When I fill up I use an ethanol treatment. Just bought some more last night at Wally mart.
Phase separation of fuel as well as rubber deterioration can wreak havoc on fuel systems & engines. You can't use too much and better to be safe than sorry if your boat sits for more than a few weeks. Certainly a must for winter storage.

From page 40 of Merc manual (Volvo is similar)...

IMPORTANT: When operating a Mercury MerCruiser engine on gasoline containing alcohol, storage of
gasoline in the fuel tank for long periods should be avoided. Long periods of storage, common to boats,
create unique problems. In cars alcohol-blend fuels normally are consumed before they can absorb
enough moisture to cause trouble, but boats often sit idle long enough for phase separation to take
place. In addition, internal corrosion may take place during storage if alcohol has washed protective oil
films from internal components.

[tgrace98]

I always fill up when I get to half a tank. The marina I fill up at only sells 91 octane with no ethanol. It’s a little pricey but my boat lives on a lift so it is what it is.