fuel consumption Merc 115 and update on previous repair issues

Madpole

Cadet
Joined
Sep 3, 2012
Messages
19
I have an 84 Merc 115 inline 6 that I have been working on and have received numerous "assists' from the Good Guys on this forum. And THANKS TO YOU ALL!
My problem was that my motor could only run at half throttle.
Well, after all the help and hours of....fuel line replacement, spark testing, compression testing, carb cleaning, link n' synch procedures, idle adjusting and dozens of trips to the lake.......I finally fixed my problem with A RUBBER BAND!

No, seriously I found that the wiring harness that comes from the trigger/spark advance....was being restricted by a captive wire bracket and wouldn't let the advance move freely! I bent the bracket open and all is well now.

Now my latest question to you all....

Now that I have this little hot rod (16 foot ProCraft bassboat) running like a scalded dog...I find the fuel consumption much higher than I remember from my last 2 outboard motors. (both mercs but smaller, 85 and a 50 horse)

How much fuel should this unit consume in an hour? the last time out, I burned about 5 gallons in what seemed to be about thirty minutes of running at a reasonable speed. (3/4 throttle at the most)
Is this normal? If not, what should I look for to bring this bad boy back to an "affordable" condition???

I can't afford to go fishin'!!!!
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,627
Re: fuel consumption Merc 115 and update on previous repair issues

I once burned 6 gal of fuel in about 20 minutes, with a Merc 1500, a full boat and at nearly WOT. Just check for leaks a the carbs and inspect the plug color. If the color is correct and you see no leaks, I think you are set up right. Max Spark Advance is at 21* BTDC?

BTW - My Merc V6 burns a lot more fuel than my old 1500.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,938
Re: fuel consumption Merc 115 and update on previous repair issues

How much fuel should this unit consume in an hour? the last time out, I burned about 5 gallons in what seemed to be about thirty minutes of running at a reasonable speed. (3/4 throttle at the most)
It will roughly burn 11.5 gallon a hour at WOT so your real close to spec........
 
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