Fuel consumption

[Andrew Leigh]

Hi

I have a 115 evinrude on the back of a 17" bowrider. I was planning to change boats to a more fishing style boat with two smaller engines. Perhaps 2 x 45hp.

I was curious as to the fuel consumption of the smaller engines. My 115 is a real gas guzzler. Any experience of the smaller engines fuel consumption?


Cheers
Andrew

 

[WillyBWright]

Re: Fuel consumption

I assume you're taliking about the inline-4 45s. They aren't particularly stingy with gas either. If you want a noticable difference, get a 4-stroke or OptiMax. But if you operate mostly at full throttle, it takes about the same amount of fuel to produce 115Hp no matter what kind of motor it is.

 

[steelespike]

Re: Fuel consumption

Unless you are looking for a backup in case of a motor failure i can't see any advantage to 2 45s. gph with the 115 is about 11 GPH,2 45s would be about
9 gph.Probably a little higher due to the twin setup. A Etec 90 runs about 8gph at wot.Of course all these figures depend on what you are pushing.

 

[Andrew Leigh]

Re: Fuel consumption

Hi guys,

thanks for the responses. Perhaps I should have given more background information.

Yeah Willy, you confirmed what I thought. It will take so much input energy (gas) to get a certain amount of output hp. What I was not sure of is that it may well be more efficient as perhaps the thrust is not proportional to hp?

Some background to answer Steelspike. My bow rider is fitted with two boards that take the place of the front and rear seats, each is equipped with a fishing stool. My hybrid fishing / pleasure boat. Unfortunately legislation in this country only allows me to venture out to sea by 1 nautical mile. Also the hull is too shallow to be safe.

As I wish to go out further to sea I am investigating a 20/22' inflatable, went to look at one yesterday, it was equipped with 2 x 30hp which I am assured is more than enough. Legislation requires, amongst other things two motors are fitted for safety reasons.

Cheers
Andrew

 

[steelespike]

Re: Fuel consumption

Do these twin requirements mean 2 motors as a primary source of power or is it possible to run a primary motor with a secondary back up motor?
2 Forty Etecs would make a nice small twin setup if you have deep pockets.

 

[Andrew Leigh]

Re: Fuel consumption

Hi Steelspike,

Two motors as a primary source. The thinking is that if one fails that you can still limp home. What I have not checked is if one could be smaller as a backup.

Speaking of which these would need to be ordered to contra-rotate?


Cheers
Andrew

 

[steelespike]

Re: Fuel consumption

Counter rotating would be ideal though on a small rig I would think it not necessary.I wonder if it would be possible to order counter rotating on smaller motors.
I do have a 10 inch left hand Michigan wheel That appears to be about right for a 50 hp. Haven't been able to find application.Though it appears like a non through hub OMC.Number appears to be S M C 655. So it seems they used to do relatively small props in left hand rotation.