Yamaha 80 HP Year 2003 Four Stroke, Spark 1 Oils Up

[roselea]

Upon starting engine No. 1 spark plug oils up within seconds of igniting engine and misses. We have tested the spark plug and it fires, there appears to be nothing wrong with the spark. Also tried a brand new spark plug and it oiled in seconds.

The engines is dismantled, have checked the rings, piston, bore, valves, guides and seals. Cannot find the cause as far as we know there is nothing else to be checked we are dumbfounded as to the cause.

There is no water in the oil, no visual cracks in head, block and piston/s.

It is a 2003 model which we bought new and have only used it for approx 18 hrs.

Every thing appears as a new motor should.

Any ideas????

 

[BruceAML]

Re: Yamaha 80 HP Year 2003 Four Stroke, Spark 1 Oils Up

It is always helpful to post your complete model number. I know that in Australia you have "World" model motors. In North America most of the models have different model numbers and some of the parts are different. Is this a model F80TLRB? Did you install an NGK LFR5A-11 spark plug? Did you gap the plug? Did you torque the spark plug? What kind of oil are you using? When you check the oil level is it above the full mark?

 

[roselea]

Re: Yamaha 80 HP Year 2003 Four Stroke, Spark 1 Oils Up

Hi BruceAML,

First of all the Model is a F80AET.
It had the original spark plug when the spark plug 1 oiled up.
We went and bought a new plug NGK LRF5A-11, gapped it and torqued it then
put it in. The same result oiled up within seconds of starting motor.

The motor missed on number 1.

The oil is Yamaha oil and the level is a little lower than the required level.

We have bought a "CLYMER" Outboard Shop Manual which ocvers 75 - 255 HP Four Stroke years 2000 - 2003 published by Primedia , Overland Park. KS.

Our motor is covered in this manual it is the 2003 model.

Enough info for you now Bruce??

Cheers
Roselea

 

[Yamajoe]

Re: Yamaha 80 HP Year 2003 Four Stroke, Spark 1 Oils Up

Did you do a compression test and or better still a leakdown test before dismantling the motor?

 

[roselea]

Re: Yamaha 80 HP Year 2003 Four Stroke, Spark 1 Oils Up

Did you do a compression test and or better still a leakdown test before dismantling the motor?

We did not do a compression test. Its been our experience in the past if a spark plug is fouling with oil that the following things can be wrong.
1.. Something wrong with the piston.
2.. Broken rings.
3.. Crack in the block.
4.. Crack in the head.
5.. Valve guides seals missing or damaged.

We found no water in the oil.

We have check all of the above and found nothing wrong.

What purpose would a leakdown test do?

 

[Yamajoe]

Re: Yamaha 80 HP Year 2003 Four Stroke, Spark 1 Oils Up

A Leadkdown test goes a long way in saving you time and money involved in tearing down the motor to confirm what you now know.