1980 Mercury 115 (cdi) gas mileage?

[Joeshow]

Hey, I'm curious if 25 litres (6.6gal) might have been 23L, 6gal.) lasting 30 kilometres (18.6mi) is good for these engines? Mostly full throttle. I'm not too sure about the weight of the boat (1975 Starcraft 16' American), guessing 1200 pounds (545kg) ? I have a 19p cupped aluminum prop on.

I would like to hear other older 115's approximate mileage with weight n such in mind!

 

[Dave1027]

Re: 1980 Mercury 115 (cdi) gas mileage?

Sounds about right. If you are concerned about gas mileage (do they call it mileage up there? How about kilometreage?) then reducing RPM will greatly help. I like to cruise about 4,000 RPM. Seems to be a good compromise between speed, MPG and engine noise.

 

[buzzm19]

Re: 1980 Mercury 115 (cdi) gas mileage?

I have read in several articles on these motors and since most older outboards are two stroke, if you go by cc's yours is 1150cc's, so if you run it at wot then you will use 11.5 gal per hour. If you check your speed then you can come up with the amount of gas usage per mi. Buz

 

[79Merc80]

Re: 1980 Mercury 115 (cdi) gas mileage?

Buzzm19. You have part of that correct. it's 10% of HP rating. But, the 1150 you see on 1978 115hp and older is not the cc's. It's the model number. The 90, 115, 125, 135, 150 inline 6's all have the same 99cid blocks (Not sure what the metric version is). Now there is a difference between the pre 1983 and post 1983 engines as pre 1983 was crankshaft rated and post was prop rated. I had a 1984 90 that burned 11.5gph at wot and the 115 from 83 on would burn 14 gph at wot. The best cruise RPM is between 4000 and 4200. You can usually tell because the engine get's a little quieter and kind of fels like it's not working as hard.

Craig

 

[buzzm19]

Re: 1980 Mercury 115 (cdi) gas mileage?

Craig, I stand corrected, and remembered that 1150 means model and not cc's of the motor.

 

[79Merc80]

Re: 1980 Mercury 115 (cdi) gas mileage?

I didn't intend to make that sound like I was scolding you. Only wanted to mke sure that the OP and other were getting the best information available. I've had the 1250, 1150, 1500, 115, 140, and 90 from 1969 through this year when I finally bought my first I/O (MerCruiser) I know, I'm stuck in a rut with regard to Manufacturer