Gas hog or is this normal?

[eterry]

Hey all, I took my 15' tri-hull, '77 85 hp Johnson out for its first run yesterday, only took one 6 gallon tank as I planned on not being out long. I started out slow and close to shore, didnt want problems in the middle of the lake, then slowly increased speed til max throttle, and only then for short periods, like 5 minutes or so til throttle back. After 1 1/2 to 2 hours of driving I stopped close to the ramp and got up to walk off a sleeping foot. I checked the tank and was shocked to find it almost empty, maybe a half to 1 gallon left.
Is this about the right fuel consumption? I have no idea what kind of prop it has, which is my next question. How do I tell what kind of prop I have, and can I get better fuel usage from a different prop? I assume it is set up for a ski rig, but not sure. I dont plan on skiing, just running across the lake and fishing, so whats the best prop for me ??

Thanks for the help.
Eterry

 

[HighTrim]

Re: Gas hog or is this normal?

The size of the prop is usually stamped on it, have a look at let us know what you find.

 

[eterry]

Re: Gas hog or is this normal?

Wow that was quick...I am at work and wont be home til about 4 pm. Will look then.
Eterry

 

[F_R]

Re: Gas hog or is this normal?

I'd say you did well. You should see what a Real gas hog can do to a 6 gallon tank.

 

[HighTrim]

Re: Gas hog or is this normal?

This will help with the prop selection if you do decide to change it.

http://forums.iboats.com/showthread.php?t=158083

 

[HighTrim]

Re: Gas hog or is this normal?

Yeah, my 200 woulda ate that tank up untying from the dock, lol.

 

[mokaction]

Re: Gas hog or is this normal?

Remeber rule of thumb.. 85 hp / 10% of fuel per hour = 8.5 gals. So you are right.

On my 225 I get about 15 to 17 gals per hr at 3500 RPMs
at full I get about 20 to 23 gal per hr at 5000 RPMs.

Get a larger fuel tank.

Larry

 

[Molaker]

Re: Gas hog or is this normal?

Boats are a little different than automobiles. For the most part, boats are for pleasure. So, gas consumption is measured in smiles per gallon.

 

[chbailey]

Re: Gas hog or is this normal?

Sounds like you did pretty good to me.

 

[offshore100]

Re: Gas hog or is this normal?

Remeber rule of thumb.. 85 hp / 10% of fuel per hour = 8.5 gals. So you are right.

Larry

that's for wot; pull back to about 3000-3500rpm's and you should do almost twice as well on your fuel economy.
So, you did about right cruising 1 1/2 to 2 hrs, eterry.

 

[eterry]

Re: Gas hog or is this normal?

Thanks one and all for the help and info. I went home and looked at the prop; it has stainless blades and some rust and corrosion on the base(?) but I couldnt find any numbers. I might take a wire brush to it and maybe see something. But it sounds like I am doing about right on fuel.

The boat came with 2 six gallon tanks and I have one also, so 18 gallons should give me plenty of boating time. Its about a 10 minute boat ride to where I crappie fish so thats not a problem.

I am used to my 14' alluminum with my 20 hp, it will go for 3 full days fishing or all day long riding around but at not the speed or comfort the tri-hull gives, so its a good trade-off.

The formula of 10% of motor size in gallons of fuel per hour is a good one and that helps a lot. Will also try to remember to not run WOT all the time. I am not looking for effeciency and know that this is for pleasure, but wanted to know if something was wrong or if thats the kind of usage I can expect. Will definately take the other tank next time.

Again, thanks for the info,
Eterry

 

[ezeke]

Re: Gas hog or is this normal?

Many propellers have the part number and size stamped on the hub, front or back depending on the manufacturer. often you need to remove the propeller to read the numbers.

 

[eterry]

Re: Gas hog or is this normal?

Someone at work told me I might have to take the prop off to get to the numbers, I guess I need to take it off and see how much fishing line is in it.

Eterry