K&B 3.5 outboard question

[RobertDoak]

So .I have a brand new 3.5 SX...out for a break in bench run...and noticed a very slight fuel mist coming from under the the starting cone and front crank bearing...this would cause a lean issue.

I never noticed anything like this on any other nitro engine and I have used a lot of them in the past...from planes to buggys..cars....boats.. etc....you get the point....so should this be a sealed front bearing....or are ther other areas I should investigate.....thanks to all..

 

[Mark Anderson]

Normal.

 

[RobertDoak]

Wow....ok...so if a sealed bearing were to be installed...would this cause a breathing or flow issue...

 

[Mark Anderson]

doubt you would notice any change in the way the engine runs.

 

[RobertDoak]

Not expecting a noticalbe way the engine runs....just stopping the fuel loss through bearing....

 

[Geraghty]

Remember the motor is being run in the vertical position....no help from gravity here...

Seeing that slight amount of fuel coming from under that front bearing is visible proof that oil is reaching the front bearing...

After installing after run oil place the motor/boat upside down until the after run appears on the bottom of the flywheel....

That's when you know the front bearing has been treated....

 

[RobertDoak]

Ok upon further inspection ....I noticed the crankshaft was as smooth as can be where the front bearing is....no spiral groove....I obtained a crank with groove...
And guess what.....no fuel spray...