# Marina Gas?



## SlimeTime (Oct 3, 2008)

OK, the 1st time I had the boat out, I mixed my own fuel, and added a can of SeaFoam. The boat top-ended at just under 40MPH (about 39). I ran low on fuel, so I filled-up at the Marina, again added SeaFoam.

When dad & I was out yesterday, the boat wouldn't top 30MPH. Granted there was some wind, which caused a little chop on the water.....but would I lose nearly 10MPH......or could their fuel be "sub-par"?

ST


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## dedawg1149 (Oct 3, 2008)

you wouldn't think gas would make you lose 10 mph ,i ran some sea foam through mine with gas that was 7 months old now it purrs like a kitten ,have you check your linkage or prop to see if it is slipping just a thought


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## Captain Ahab (Oct 3, 2008)

Chop will make you loose 10 mph easy. Where you also running into the wind?


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## SlimeTime (Oct 3, 2008)

I checked things over while I was into the motor today, didn't see anything that looked out of place.

Capt'n- Yes (wind), but neither direction (with/against) made a difference. May just be a matter of seeing what she'll do next trip out.

ST


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## dedawg1149 (Oct 3, 2008)

maybe you should ask bassboy.


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## Quackrstackr (Oct 3, 2008)

Captain Ahab said:


> Chop will make you loose 10 mph easy. Where you also running into the wind?



Light chop makes my boat run faster.

When did you run your boat the first time? Outboard engines really fall off on performance when the air and water heat up. Outboards with a prop maxed out for speed also fall off pretty quick with a load in them. An extra person and a full fuel load may make a pretty good difference.


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## SlimeTime (Oct 3, 2008)

DD-May have to do that (if he doesn't see this & reply), but I was gonna wait & see if I needed help with the starter.....and just make it a 2-fer :mrgreen: 

QS- Stumpknocker & I took the maiden voyage about a month ago, and it was hotter'n hades then. Basically the same weight (2 persons) and roughly same gear (though I was carring an additional 18 pounds of my homemade anchor this time, though the lack of Scotts cooler should have equaled that).

ST


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## Zum (Oct 3, 2008)

I hope it's not related but aren't you having trouble with your outboard?
Maybe it's related,you say it's not starting now.
sry,Can't remember your other post./


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## SlimeTime (Oct 3, 2008)

Zum said:


> I hope it's not related but aren't you having trouble with your outboard?
> Maybe it's related,you say it's not starting now.
> sry,Can't remember your other post./



Yeah, but it's an unrelated (starter) problem.

ST


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## Zum (Oct 3, 2008)

What are(did)you using to measure the speed?
Maybe thats messed up?(guessing)
Did it seem like you were going slower?


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## SlimeTime (Oct 3, 2008)

Zum said:


> What are(did)you using to measure the speed?
> Maybe thats messed up?(guessing)
> Did it seem like you were going slower?



Speedo in the dash. Yeah, seemed slower...I was hoping to see dad "white-knuckled" :mrgreen: 

lol
ST


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## bassboy1 (Oct 3, 2008)

Were both trips at about the same time, or similar outside temperature? I don't know too much about it, but while I was reading up on another outboard I considered buying, I remember reading a thread where somebody complained that leaving in the morning he was getting a better speed than coming home in the afternoon. Or vice versa. I didn't really pay attention, as it didn't pertain directly to the motor that I was researching. But, it was mostly due to temperature of the air, and what the air temp does to the density of the fuel, or something along those lines. So, that is one possibility. 

The other would be the different places that you bought gas. You may have bought all your shore gas from a place that for whatever reason, hasn't started putting large quantities of ethanol in the gas. The marina may have had gas with a heavy ethanol concentration. If you do some readings on some of the numbers as far as fuel consumption goes on the newer trucks that have a consumption meters on the dash, they can see that they get significantly MPG readings on fuel without ethanol. On a truck, the difference is seen in consumption, as it just has to work a little faster, thereby eating more fuel, to achieve the same purpose, as it isn't constantly run at the redline. But, on an outboard, you are always working it as hard as it goes, so when faced with lesser quality fuels, it can't work any faster, so the results are shown in a lack of speed. 

Thirdly, it could just be because you have a merc. :shock:


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## Popeye (Oct 4, 2008)

SlimeTime said:


> Speedo in the dash. Yeah, seemed slower...I was hoping to see dad "white-knuckled" :mrgreen:
> 
> lol
> ST



Well there's your problem. I'm lucky if I can get the same speed twice on the dash speedo. All it takes is a little piece of crap to get stuck in the pickup home and your speed is wrong. You need to use a GPS to accurately determine your speed. Marina gas can sometimes be old (depending on their business) Did you use the correct octane? Motor trimmed the same way each time? Deeper V boat with chop will go slower as well. My bass boat will pick up a little speed with a VERY light chop (more like heavy ripples). But I only top out about 45MPH on a good day.


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## SlimeTime (Oct 4, 2008)

It was hot when I used the boat for the 1st time, it was pretty cool Thursday. I'm aware that cooler air is denser (and moist air even more so), and can actually increase power. Wished I wouldn't have completely filled the tank at the marina, especially at $5 a gallon :roll: never again, if 16 gallons of fuel ain't enough, I'll take a couple 5 gallon jugs. I may not run this tank of gas out before winter, but I believe it's the fuel causing the problem.


My speedo runs off the motor, no tube or wheel outside the boat. When I fueled-up they were actually closed, the guy came-out & turned the pumps back on. They only had 2 pumps, premix & not.

ST


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## papasage (Oct 21, 2008)

after seafoam i think it is recomended to change plugs . and running 2 cans in a row i think is to much. 
change plugs and re mix gass to proper mix and no seafoam . 
my 1979 55 hp run the same with me alone and another man thesame size 235 lbs. using the same GPS a garman 72


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