What grade fuel are you running?

[Howard Sterndrive]

Re: What grade fuel are you running?

1999 Necky Kayak.
runs on just about anything, but likes Mini Wheats, Blueberry smoothies, Wendy's Jr. Hamburger Deluxes and Folger's coffee.
And these during a refuel stop:

 

[jkust]

Re: What grade fuel are you running?

Sig boat, 4.3 liter. Has dieseled just a bit since new if you shut it off abruptly after a long, hard run and so use 89 or 91 which ever is available. Keeping it running for a minute before shutting off stops the dieseling if using 87 as well but don't always want to do that. All of the fuel I have ever used has been E10. I'm in MN where we invented ripping people off with forced ethanol.

 

[tonyjh63]

Re: What grade fuel are you running?

So, most of the time, a higher octane fuel is only useful if your engine is tuned for it (just like in automotive engines), right? I just thought that, maybe, since boat engines are under a heavier load, they might benefit from higher octane fuel, even without advanced timing.

 

[HT32BSX115]

Re: What grade fuel are you running?

So, most of the time, a higher octane fuel is only useful if your engine is tuned for it (just like in automotive engines), right? I just thought that, maybe, since boat engines are under a heavier load, they might benefit from higher octane fuel, even without advanced timing.

Um, no. Only if the engine is high compression. (marine engines are usually NOT high compression)

Load has nothing to do with it. If modern marine engines are "tuned" (timed) right they're fine on the fuel they're rated for regardless of "load".

 

[rfdfirecaptain]

Re: What grade fuel are you running?

87 Octane with 10% Ethanol - purrs like a kitten, with no spark knock - idle speed is set at 750rpm
Crownline CR250
Volvo Penta 740 Original was 330 HP - repowered in 2011 with a 420HP engine = to a Chevy 454
Raleigh, NC

 

[crabby captain john]

Re: What grade fuel are you running?

90 octane ethanol free!

 

[Scott Danforth]

Re: What grade fuel are you running?

Any actual advantage to running a higher octane fuel instead of basic 87?

because my compression ratio went from 9.4:1 to about 10.6:1 going to vortec heads and I dont want to chance detonation.

 

[dingbat]

Re: What grade fuel are you running?

87 Octane E10
1997 Grady White 226
Evinrude 3.0L - 2 stroke (W/P Ratio: 2.0 lbs/hp)
Chesapeake Beach, Md.

 

[WIMUSKY]

Re: What grade fuel are you running?

I run premium, 91, mainly because I "heard" that as a boat sits the octane levels decrease. How much and at what rate, I have no idea. Nor do I know if it's true. And my boat seems to sit a lot. The fact that premium around here doesn't contain the E word is just a bonus. If someone were to tell me the whole thing is a wives tale, I'd still run premium since my Johnson 4 stroke hasn't skipped a beat. If it aint broke.........

 

[jeff.nelson83]

Re: What grade fuel are you running?

Well in Central illinois on 87 ethanol gas its run fine but at Lake Norfork in Arkansas 87 marina gas makes it diesel like crazy. Dont now why?

 

[jeff.nelson83]

Re: What grade fuel are you running?

Next tank is going to be 89 marina gas with out ethanol and we will see if there is a difference, beside the price.

 

[oldjeep]

Re: What grade fuel are you running?

Next tank is going to be 89 marina gas with out ethanol and we will see if there is a difference, beside the price.

Just be aware that if you have a carb that you will always notice the difference between pure gas and E10. You'll run a bit leaner on E10 since it has less energy than pure gas. I've got mine adjusted for E10 since that is what I run primarily. If you've got fuel injection it won't matter, it'll adjust for you.

 

[Scott Danforth]

Re: What grade fuel are you running?

Well in Central illinois on 87 ethanol gas its run fine but at Lake Norfork in Arkansas 87 marina gas makes it diesel like crazy. Dont now why?

Because you believe the decal on the side of the pump. first, its a minimum rating of octane (legally they can sell a higher octane than published). secondly in many cases the 10% ethanol is supposed to be a maximum amount (legally they are not allowed to have a higher E rating). however I know that both Kawasaki and Briggs have found up to 20% at a few stations.

 

[bruceb58]

Re: What grade fuel are you running?

The difference in stoichemetry between E10 and E0 is around 4%. Can't imagine being able to tune a carb to that close of a difference in a boat. They are all set up slightly rich to begin with. Just go up 1000 feet from sea level and that makes up the difference in the E10. Its so slight, it just doesn't matter

If you've got fuel injection it won't matter, it'll adjust for you.

Unless your fuel injection in your boat has O2 sensors, it won't be adjusting for you.

 

[oldjeep]

Re: What grade fuel are you running?

The difference in stoichemetry between E10 and E0 is around 4%. Can't imagine being able to tune a carb to that close of a difference in a boat. They are all set up slightly rich to begin with. Just go up 1000 feet from sea level and that makes up the difference in the E10. Its so slight, it just doesn't matter

Unless your fuel injection in your boat has O2 sensors, it won't be adjusting for you.

The 3.0L are set too lean to begin with - as are most modern carb boats so that they meet emissions.

As for the FI - how many open loop fuel injection systems are actually around?

 

[agallant80]

Re: What grade fuel are you running?

87 pump Unless I am out on a longer trip and have to fill up at the fuel dock.

 

[bruceb58]

Re: What grade fuel are you running?

As for the FI - how many open loop fuel injection systems are actually around?

Every one in a boat unless it has catalytic convertors which is just the last few years.

So you are saying you actually changed the jets in your carb?

 

[oldjeep]

Re: What grade fuel are you running?

Every one in a boat unless it has catalytic convertors which is just the last few years.

Why would it matter if it has a cat? I'm talking about an upstream sensor - the one that determines the air fuel mix, not the downstream that only tells if the cat is working.

 

[bruceb58]

Re: What grade fuel are you running?

Why would it matter if it has a cat? I'm talking about an upstream sensor - the one that determines the air fuel mix, not the downstream that only tells if the cat is working.

Because it needs an O2 sensor to make sure the cat doesn't get ruined.

Before Cats, there were no O2 sensors in boats. Hard to have an O2 sensor work in a wet exhaust too.

 

[oldjeep]

Re: What grade fuel are you running?

Hard to have an O2 sensor work in a wet exhaust too.

Not really, aftermarket has been making these for years