Lots of soot

[Big Block Power]

I run 87,89,and 91 all non ethanol and never noticed soot with any of them. Matt really turn off CC
Why do I not believe you.

[cmattj]

I run 87,89,and 91 all non ethanol and never noticed soot with any of them. Matt really turn off CC
Why do I not believe you.

Never said I turn it off. When I do it’s called CC ( conversation control) haaa!

But as you currently run below water line it’s blended exhaust as compared to a top layer .
Soon my buddy you too will have worries of soot!! Soon!! CC is worth it

[tsouthard91]

Matt, so you run 87 in your twins currently?

I am running 89 during the year and put 93 in when putting her up in storage for the winter, with fuel stabilizer added just for good measure.

Oh and agree with Nauti, turning captain's call off is not an option.

Hey Southern.
Yes... Been doing it for the last year , and it has reduced transom soot for me.

I used to worry about one engine sensing ping or knock, and reducing the timing just on that one engine during that key cycle. But then I made the change and went to 87. I have scanned both engines after running the 87 fuel and have not had a timing reduction event in either of them. (the ecu will make a timing map change automatically). So she likes the 87 Octane as it can be expected she would.

As we have discussed in other threads higher octane rating is increasing the engine ability to resist knock or ping during the combustion process. The trade off is an obviously a less explosive combustion in the cylinder, thus resulting in lower power level.
Any 4 stroke gasoline combustion engine will make the most cylinder expansion power right to the very point of a ping or knock . By increasing your octane level on an engine that doesn't ping currently you will effectively reduce the power of the cylinders thermal combustion.

Oh and since they all run rich anyway for the lugging marine world environment, and only a few models require 91octane.. Enjoy the 87

Am I reading this right? Using lower octane fuel will allow my engine to make more efficient power?

[cmattj]

Matt, so you run 87 in your twins currently?

I am running 89 during the year and put 93 in when putting her up in storage for the winter, with fuel stabilizer added just for good measure.

Oh and agree with Nauti, turning captain's call off is not an option.

Hey Southern.
Yes... Been doing it for the last year , and it has reduced transom soot for me.

I used to worry about one engine sensing ping or knock, and reducing the timing just on that one engine during that key cycle. But then I made the change and went to 87. I have scanned both engines after running the 87 fuel and have not had a timing reduction event in either of them. (the ecu will make a timing map change automatically). So she likes the 87 Octane as it can be expected she would.

As we have discussed in other threads higher octane rating is increasing the engine ability to resist knock or ping during the combustion process. The trade off is an obviously a less explosive combustion in the cylinder, thus resulting in lower power level.
Any 4 stroke gasoline combustion engine will make the most cylinder expansion power right to the very point of a ping or knock . By increasing your octane level on an engine that doesn't ping currently you will effectively reduce the power of the cylinders thermal combustion.

Oh and since they all run rich anyway for the lugging marine world environment, and only a few models require 91octane.. Enjoy the 87

Am I reading this right? Using lower octane fuel will allow my engine to make more efficient power?

Yes you read it correct. Told you its a long story and would actually get longer. So ill keep it brief.
Octane rating increase is not a instant power booster. The misconception that high octane fuel makes more power is only in the event that a 4stroke gasoline engine would ping or knock with out it. This all based on timing curves, and total advanced timing in relation to compression in the cylinders through out the rpm range.

[tsouthard91]

Interesting, this is way over my pay grade, so I will take your word for it.

[NautiGirl]

Thanks Matt. I will give these a shot.

I am hesitant to run 87 as I only have access to the ethanol version of that.

I was as well....
My last boat , and my current have twin 496 with CC. The change to 87 octane is going to be probably the biggest factor in reducing soot on the transom.
Look for 10-15% percent ethanol in a 87 and you will be fine. You have a lot of outings anyway so it’s not an issue.

Last tank of the year fill her up with your non ethanol blend.

I am running 89 during the year and put 93 in when putting her up in storage for the winter, with fuel stablizer added just for good measure.

Don't bother with the tank of 93 before storage, octane has nothing to do with how long the fuel stays fresh. The money would be better spent on a fuel stabilizing treatment. We generally go /w the Blue Marine Sta-bil.

Interesting, this is way over my pay grade, so I will take your word for it.

You should, he is right. lol

[Bfun220]

I believe most top off with 93/premium because it is the only ethanol free gas in their area. But like you said there are fuel treatments that cover that.

[NautiGirl]

I believe most top off with 93/premium because it is the only ethanol free gas in their area. But like you said there are fuel treatments that cover that.

That I get. Stupid Corn.

[2ridgebacks]

I believe most top off with 93/premium because it is the only ethanol free gas in their area. But like you said there are fuel treatments that cover that.

That I get. Stupid Corn.

Corn isn’t stupid. Corn makes bourbon.

[AsLan7]

I believe most top off with 93/premium because it is the only ethanol free gas in their area. But like you said there are fuel treatments that cover that.

That I get. Stupid Corn.

Corn isn’t stupid. Corn makes bourbon.

.
I love corn ....it’s the donut of the vegetable group.Tastes great with no nutritional value.

.

[NautiGirl]

I believe most top off with 93/premium because it is the only ethanol free gas in their area. But like you said there are fuel treatments that cover that.

That I get. Stupid Corn.

Corn isn’t stupid. Corn makes bourbon.

I can't really argue that.

[cmattj]

I believe most top off with 93/premium because it is the only ethanol free gas in their area. But like you said there are fuel treatments that cover that.

That I get. Stupid Corn.

Corn isn’t stupid. Corn makes bourbon.

I loce bourbon.. that means I loce corn, and ethanol?.. sheesh where does it end

[AsLan7]

Great clip matt!

[shrfdeputy]

Another thing to check is your flame arrestor. My carb'd BB definitely runs rich, but making sure the flame arrestor is clean helps a bunch. We had a backfire issue I COULD NOT figure out last year and that ended up being the problem. Last week I had it take a little longer to start then I would have liked so I checked it again. It was a little dirty so I cleaned it, and it fired right up the next time out. Definitely something to check.

[MikeBo]

Corn makes whiskey, and whiskey makes my honey a little frisky! Corn is a good thing!

I am glad I have been pissing away $ on premium, shouldn’t one of you told me this before?