BF5 loses oil...

[longshanks]

I have a 2003 BF5 that has fairly low hours on it. Probably somewhere around 100 hours, used as both a primary power source on my small boat, as well as an auxilliary kicker on my 15' boat. I have always changed the oil and plug on an annual basis.

This weekend I noticed some oil on the water when I used it. I ran it for a while, and it started to run sporadically, with RPMs fluctuating a lot. I checked the oil, and found no oil on the dipstick. This is obviously surprising, as it was checked, and full to the top, last weekend. Anyway, I was on the water, so I topped up the oil, and changed the spark plug (sooty black). The motor resumed working as normal, but I am still seeing some signs of oil leaking onto the water. The exhaust port at the back of the leg is also black and sooty, more than normal.

This motor has always been reliable and clean running for me, so I would like to repair it, if possible. Any suggestions on what I should be looking for?

thanks.

 

[longshanks]

Re: BF5 loses oil...

still trying to figure how the oil got out of there. Could it be burning oil? How would I know that?

Another explanation is that the oil leaked out through the carb, when I was carrying the motor from point A to B. Always stored upright, or on it's (proper) side when transported. Carried by handle at front of motor, and sometimes may get tipped with leg slightly higher than powerhead... Could this have caused me to lose that amount of oil?

 

[longshanks]

Re: BF5 loses oil...

OK, for anyone who is reading this, it seems that my problem is fixed.

I inspected the motor, and cleaned the carb, although it didn't appear to need cleaning.

I believe that the problem of lost oil is a result of carrying the motor, and briefly tipping it in a manner that caused some of the oil to tip out of the carb. Manual says to always transport it upright, and store either upright, or on it's designated side.

Another possible problem is that I was running it with the exhaust port (on the back of the leg), sitting underwater. Trolling for several hours, in this position, may have resulted in back-pressure, and forcing the oil out of the carb??? At any rate, I have since mounted the motor higher, and it seems to run much better.

Posted here in case some of you are having similar issues. It seems to be working 100% now.

cheers

 

[JUSTINTIME]

Re: BF5 loses oil...

sounds right
keep an eye on it

 

[longshanks]

Re: BF5 loses oil...

I am bumping this back to the top, in case my experience here helps anybody out.

I have been running this motor all spring on my small boat without a problem. When I put it back on the large boat, on the kicker bracket, it is mounted a bit lower, so the exhaust port sits at or below water level. In this position, I am watching this motor drop oil out of the exhaust port. I can only conclude that the back pressure of the water over the exhaust causes the motor to drop oil. If it is mounted higher (as the owner's manual says to do), it runs like a top, without a drop of oil loss.

has anybody else had this problem, or can you tell me if this makes sense?