17 Gallons of Fuel 8 oz of oil used. Is this normal?

[w2much]

I have an 86 Yamaha 50 HP Long shaft electric start which runs like a dream. I'm old school and have been adding oil to my fuel, not fully trusting the oil injection system. Not that it has been a problem I just feel more assured if I add some to the tank. Have owned this motor for several months. I have noticed that it does not use much oil. This weekend I measured the amount of fuel used vs the amount of oil consumed. I used about 15 to17 gallons of fuel and only 8 ounces of oil. This is for the most part at 2200 to 2300 RPM, I troll for most of the day. I rarely have a chance to run WOT as this engine is on a 17 Ft aluminum Gregor which is used in the ocean (San Diego Ca.) . I realize the mixture is relative to the RPM's not neccesarily 50:1. My question is does this seem a bit overly lean on the lubrication? Any suugestions or advice is appreciated.

 

[Silvertip]

Re: 17 Gallons of Fuel 8 oz of oil used. Is this normal?

Most engines will live quite well with very little oil at low RPM. It think the numbers you show are quite normal at 15 gallons. The 15 - 17 gallon figure will alter things considerably as that's not a very accurate measurement since 50:1 is a pint of oil in 6 gallons of fuel. A couple of gallon difference would translate to a sizeable error.

 

[Ray Neudecker]

Re: 17 Gallons of Fuel 8 oz of oil used. Is this normal?

No it is not normal. Not even at trolling speeds. 8oz to 6 gallons would be 100/1.

 

[Silvertip]

Re: 17 Gallons of Fuel 8 oz of oil used. Is this normal?

If the pump is a constant 50:1 ratio oiler regardless of engine RPM that's true. If its a variable ratio oiler, its not.

 

[bingster]

Re: 17 Gallons of Fuel 8 oz of oil used. Is this normal?

Doesn't seem right to me...a little lean. If I were you I'd take it to a qualified Yamaha Technician to diagnose before seizing the powerhead.