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Engine Oil Black Honda BF90

bbaker

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"In fall of 2008 I paid a resp

"In fall of 2008 I paid a respectible marine shop to winterize my motor. ($180) They wound up fogging the carbs on my 4 stroke, and didnt drain the float bowls. Heard this was a no..no? This led to problems in the spring of 2009.
So I decided to winterize this year myself. I found the engine oil was BLACK. Looked like the oil from a car which had 5000 miles on the oil. Can 10W-30 engine oil get black in 1 season with 50 hrs tops? (2007 motor)
Another thing I found...I think he put on a faulty Merc fuel/water separator...which had a solid rust ring on the outside of the seal. Changed that in the Spring of 2009 when I saw the rust.

When I changed lower unit oil, it looked brand new. Still yellowish in color. No water. Puzzles me how the lower unit oil could look so new, and the upper engine oil be so black?

Doing this myself from now on.

Just some advice I didnt do myself. Always check your oil levels after you get your boat back from servicing. Look to see if they greased all fittings, and double check your filters. This might save you a problem come spring."
 
"It is possible that this engi

"It is possible that this engine has not been broken in properly to seat the rings and valves. After the initial breakin (usually 25 hours) the engine should be run at WOT as much as possible over the next 50 hours or so to properly seat the valves and rings. I've made the mistake of "babying" a new four stroke myself, with similar results. So, if the engine is not broken in properly and/or you are doing a lot of low speed running, like trolling, it is quite possible to get very dirty oil in 50 hours. Also, contrary to the Honda maintenance manual, change the oil filter every time you change the oil - every 100 hours, or every season."
 
"Thanks for the input. I do

"Thanks for the input. I do not baby this motor. Been around them my whole life. I know to slap it quick into gear, I normally run just below WOT at 5000 RPM's , (21 mph)....and change the RPM's often. Its on a Pontoon Boat...and actually pull the kids tubing at WOT alot.

I was peeved when I thought back I paid $180 for last year's winterizing and had a carb prob spring 2009...Watching that Black oil come pouring out the drain, burned me even more. (Didnt look so back on the dip stick back in July) I know these engines run hot at 5000+ RPMs...which can breakdown oil faster. Just didnt think at 50 hrs it would be that fast. Yes I changed the filter this year.

Wasnt smart enough to look at the filter last season and see if they changed it? I guess marking them with a scratch before it goes in would be a great test.

Problem is I trust these guys, and I am sure the owner would be ticked off knowing his shop boys could be cutting corners."
 
Roger that! Always best to pul

Roger that! Always best to pull your own maintenance - then you know it was done right.
 
"Check the t-stat to make sure

"Check the t-stat to make sure that it is not stuck in the open position. If the t-stat does not close the motor will run cold and the rings will not seat in the bore, causing excessive blow-by."
 
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