Fouled plugs

stebek

Recruit
Joined
Aug 11, 2001
Messages
2
I have a 1993 70 horse Force outboard with low hours on a 17 foot Maxum Bowrider. It has been very reliable. The last few times out it slowly started to lose power while attemting to increase speed. Fuel line was clean and breathing. Checked plugs(correct plugs that I have been using problem free for years) and all three were fouled with a dark hard oil. Cleaned them and it ran fine for a few minutes then same occured. Engine gets low usage.(At summer camp in Maine, short season.)I have not decarbed,was told WOT does the same.For Oil mix I have been using Penzoil this season. I use 16oz. for 5.5 galls. Any ideas or suggestions would be great. Steve in Danvers MA
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,598
Re: Fouled plugs

Oil ratio sounds right (50:1). Are you sure you didn't pick up motor oil by accident? There are lots of preferences where 2-cycle oil is concerned, but no TCW-3 rated oil should foul in the way you describe. <br /><br />If it's not the oil or oil mix, it sounds like the next step would be to check the carb setting for an over-rich mixture.
 

wvit100

Chief Petty Officer
Joined
May 6, 2002
Messages
416
Re: Fouled plugs

50:1 ratio should be 6.25 gallons of gas to <br />16 oz. of oil. I usually run about 7 gallons to 16 oz. oil in my force, but I don't hardly ever run at WOT.
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,598
Re: Fouled plugs

50:1 is 2.56 oz oil per gallon of gas, but that is a little difficult to measure (like 6.25 gal of gas). I recommend you round to 3oz per gallon, and don't run with less oil -- your mix is OK. You can err a little on the safe side without fouling plugs, or you can take a chance on less oil and perhaps burn up an engine. If you can't safely run at WOT (at least with respect to your oil mix), you have the wrong mix. 50:1 is right for all rpms.
 
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