Fuel Consumption

capecodangler

Recruit
Joined
Jul 18, 2006
Messages
2
I've got a rebuilt 1985 115 HP Evinrude that is a major gas hog. It seems like it sucks even more than the 1972 model that it replaced. Would miss firing on one cylinder cause this? I can detect an intermitent hiccup when idling. Any suggestions would be greatly appreciated.
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: Fuel Consumption

Hi angler

Any ignition problem will take it's toll on gas milage. Have you done anything to diagnois the problem yet? Any parts replaced such as spark plugs, Etc? Spark check? Does it do this at all speeds? Can you give us some history on the motor, such as was it ever running right or is this motor new to you? Did it sit for a long time between use? Why the rebuild on the motor? A little more info will help....
 

capecodangler

Recruit
Joined
Jul 18, 2006
Messages
2
Re: Fuel Consumption

Rick,

We had a 1972 Evinrude on her but after 30 years in the salt it was just cooked. One cylinder was just totally gone. The boat sat in the yard for about 5 years and finally last summer my father had someone put a re-built 1985 evinrude on (I think just the engine head as it looks like the old transmission is still on there). We ran it a couple of times last fall then winterized it tarped up the boat and let her sit until later April at which point a I just ran some new gas through her and started fishing. The problem is that the range seems to be severely deminished versus what I recall the old engine could do. Also it seems like it is expelling unburned fuel - when idling at the moring I can often see a sheen of gas on the water. We have not replaced plugs this year or done a spark check. Also as I mentioned, it sometimes sounds like it is not firing on one of the cylinders as I can detect a hiccup when idling. My inclination is to replace all the plugs and see if that helps - but just a shot in the dark.

Thanks!
CCA
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: Fuel Consumption

Running a 115 crossflow on plane on Cape Cod Bay will cost you about 16 gallons per hour. You do the math.
 

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: Fuel Consumption

capecodangler...possible that you have a fuel leak? If you have one of the pre-vro fuel pumps, the diaphram can leak for awhile with no noticeable symptoms other than the oil slick you've seen. You can observe fuel dribbling out while you pump the bulb or while it's running. Any evidence of flooding in the lower cylinders - as in leaking into the pulse line?

Sounds like compression & spark test might be helpful.
 
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