Bad gas mileage

[rainman99]

I have a 1985 Johnson 90 Hp. Got it at the begining of June , have had it out 5 times now first 2 times I was getting 2 miles a gal. of fuel. The past 3 times im only getting 1 mile a gal. average speeds 25-30 mph mild curent and chop on the Ohio River ,useing Quick Silver med grade gas at a 50-1 mix. Motor on muffs little smoke fuel smells a litte rich , plugs have a little carbon build up have 125 psi compression runs and idels great on and off the water. What now adjust jets and timeing? Thanks for any help you can give.

Rainman

 

[kenmyfam]

Re: Bad gas mileage

Before you rip anything apart, gauge your fuel usage in gallons per hour. Miles per gallon is not a good way to measure fuel consumption on a boat in my opinion.
Your 90hp should use around 9 gallons per hour at WOT and at a comfortable cruise significantly less.

 

[tashasdaddy]

Re: Bad gas mileage

agree, boats are not measured in MPH, it is Gallons per hour. you 90 hp at wide open throttle will burn 8-9 gallons per hour.

1985 90 does not have any adjustable jets. timing and linc n sinc is never a bad idea. this works great for timing, and is very easy. http://forums.iboats.com/showthread.php?t=228183

this does not apply to you now, but good info. http://forums.iboats.com/showthread.php?t=330129