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I have a 2000 F115 4-stroke. It had a recent full service by a Yamaha shop. It is running great, but the oil level is rising and it smells like gas. I noticed the problem about 10 motor hours ago. When I checked the oil it gushed out of the dipstick hole. We drained it (thinking maybe the shop overfilled it), changed the oil filter and filled it to the half-way mark. Another 10 hours on the motor and now the level is about 1 inch overfilled and the oil definitely smells like gas. Any ideas??
I have ran into this several times with customers that just putt around with the 4 strokes. I had a customer that had tandem 115's rigged on a survey boat. He idled all day and the motors never got up to proper operating temperature, causing gas to blow by the rings, therefore gas in the crankcase. Yamaha recommend running the snot out of the motors for a few minutes getting them up to temp before idling all day. You might try that, I don't know how you are operating it, but if you are an idler, this could be your problem. Remember that once they are good and hot, idling is not a problem. I hope this helps.
Wow.........didn't know that........thank you for the info.......
Of course, I generally don't have any trouble keeping the RPM's up........ http://www.bassboatcentral.com/smileys/devil.gif
Boy, you learn something everyday! I have a 06 F150, and quite a bit I idle all day. I don't have that problem, but it is new and I don't want it to start. Now I have a reason to tell my wife we have to barrel ass down the river before we putt to the fishin hole. http://www.bassboatcentral.com/smileys/Laugh.gif Thanks for the info.
There was also a bulletin out from Yamaha about the F115 motors leaking fuel into the crankcase via the mechanical fuel pump, so take a look at that. Pull the fuel pump and see if there's evidence of fuel getting through the shaft to the crankcase.
Mike
I know the problem Brad is refering to.....However, yours sound a little more serious than just the oil level creeping up the dip stick. You might want to get it checked out.
Thanks for all the replies. Right now I am looking at relacing the fuel pump inner diaphram, since it has oil on one side, and fuel on the other. I couldn't find a yamaha bulletin mentioning that diaphram leaking, but it seems the most likely place for that amount of fuel to pass into the crankcase.
Some mornings I did get the boat warm before trolling, and sometmes I started trolling just outside of the dock. It just seems that that would be way too much fuel for a blow-by situation, especially since the compression test was good. (168-165-149-169)
Thanks,
Ron
19' Arima Sea Ranger
F115 Yamaha
Why is that one cylinder 20lbs lower than the rest?
I wonder too, but every mechanic I've spoke to says the readings are fine. (within 25 to 30 lbs. of each other)
Hamfisted,
Could you send me a link for that bulletin.
Thanks,
Ron
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Gottafish2 »</TD></TR><TR><TD CLASS="quote">I wonder too, but every mechanic I've spoke to says the readings are fine. (within 25 to 30 lbs. of each other)</TD></TR></TABLE>
Me personally would not settle for that. With in 10lbs maybe if they were all spread out....But you only have one that is really different than the rest.
after reading this, I went out and checked my oil level. When I changed it for the first time ( @ 10 hrs) about 10-15 hrs ago, I had it at about a quarter of an inch from the top of the "checked" area. Now it is at about 3/8" above the checked area (too full) and smells gassy.... NOW WHAT? Change it again? You can bet your last nickel I'll be talking to the Yammy folks in Birmingham at the FLWTC in a couple weeks...
I putt around a fair amount, but then again, I keep her between 5 & 6 K a good bit of the time...
Send an oil sample into Blackwell Labs for an oil report. It will give you verified results when you talk to Yamaha.
Should I worry about this with my F150 or is it isolated to the F115's? I am sure they are the exact same design though, just one is bigger.
Guys I have had this discussion on here before. Basicly I discovered that when filling my motor up I only fill it until it is between the full and low mark. DO NOT Fill it to the full mark. I think the motors could stand a little hotter thermostat in them. However, the problem with the 115 (original post) is greater the a "little" gas in the oil. I think he need to get it checked out.
yeah he seems to have a serious problem... I would say mine's built up about a half quart in about 12 hours runtime..
more info. http://www.bbcboards.net...20678
I bet that cylinder with 149lbs is allowing blow by.
You might consider the fuel pressure regulator (if it has one). If it is bad, maybe you are getting too much gas into the cylinders and the excess is blowing by the rings on the compression cycle. Might sound far fetched, but it's another thing to eliminate when troubleshooting. The computer may not monitor the fuel pressure, I have no idea, but if it doesn't, the dealer may not have found it during the checkup.
That's probably not it if it's running fine. Do you smell raw fuel when running?