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2000 Honda BF45 oil leak from dipstick when running

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seaspearo

New member
Noticed there are some engine oil yesterday went out fishing, also feels like more white smoke than normal. Opened the engine cover, noticed there are some engine oil in the oil pan. Googled and suggest might be PCV valve blocked. Sprayed some baby powder, start the engine and I can see very small trace of engine oil around dipstick seating. Resprayed baby powder and left it over night, no new oil leak. So only oil leak when running, maybe excessive crankcase pressure? Take the breather tube from cylinder head and air intake, the tube looks fine. I know for car engine most likely it is PCV valve, but outboard use crankcase ventilation system, what should I do now?
 

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Hi,

I haven't worked on this model so I am not sure about what to look for specifically.

I couldn't find a listing for a 45hp Honda later than 1997 but the link below seems to show that there's probably a baffle in the valve cover for directing crankcase gases out to the engine intake.


The link below illustrates that there is a crankcase venting hose to the intake muffler and, even though it doesn't show it, I think the hose (item 10) is routed to a nipple on the side of the valve cover.


You might want to check that hose and possibly even the baffle inside the valve cover to make sure there's no blockage or damage to either one.

Beyond that, excess crankcase pressure is typically caused by poor cylinder sealing at the pistons and is usually caused by worn piston rings. Something a cylinder leak down test would likely show.

If this is a high hour engine or one that's not received regular oil changes over it's life that could be the reason for any wear.

Good luck.
 
Thanks for the reply and suggestion! I bought the boat in 2000, so I thought the engine is 2000, maybe it is earlier. Anyway BF35 BF40 BF45 and BF50 are same mechanically. I change oil and maintenance regularly, engine is old but looks in good shape.

I will open the crankcase cover to see if there is a baffle or PCV valve like thing. When I google honda bf40 crankcase breather, I see this part, but cannot find it on the diagram or service manual.
www.ebay.com

Engine Crankcase Breather Element Standard BF40 | eBay

The engine types may include 3.7L 226Cu. V6 GAS SOHC Naturally Aspirated,4. V8 FLEX SOHC Naturally Aspirated,4.7L 287Cu. V8 GAS SOHC Naturally Aspirated. This part fits vehicles made in th e following years 2001,2002,2003,2004,2005,2006,2007.
www.ebay.com

Thanks!









jgmo said:
Hi,

I haven't worked on this model so I am not sure about what to look for specifically.

I couldn't find a listing for a 45hp Honda later than 1997 but the link below seems to show that there's probably a baffle in the valve cover for directing crankcase gases out to the engine intake.


The link below illustrates that there is a crankcase venting hose to the intake muffler and, even though it doesn't show it, I think the hose (item 10) is routed to a nipple on the side of the valve cover.


You might want to check that hose and possibly even the baffle inside the valve cover to make sure there's no blockage or damage to either one.

Beyond that, excess crankcase pressure is typically caused by poor cylinder sealing at the pistons and is usually caused by worn piston rings. Something a cylinder leak down test would likely show.

If this is a high hour engine or one that's not received regular oil changes over it's life that could be the reason for any wear.

Good luck.
Click to expand...
 
I don't know about that part but if your outboard has the hose from valve cover to intake muffler then I don't think that valve would apply.

The baffle inside the cover is the device that directs the vent gasses. It's a pretty common method for engine manufacturers to use for doing that.

Good luck.
 
Just opened the crankcase cover, the breather tube hole just connect to black rectangle thing inside of the plastic cover. Seems like one piece of the cover, no screw or locking pin, do I need try to open the black rectangle thing?

Thanks!






jgmo said:
I don't know about that part but if your outboard has the hose from valve cover to intake muffler then I don't think that valve would apply.

The baffle inside the cover is the device that directs the vent gasses. It's a pretty common method for engine manufacturers to use for doing that.

Good luck.
Click to expand...
 

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NO! I don't think that is serviceable and any attempt to open it up will probably ruin it. In the automotive world (where I came from) if you thought there was an issue with that "breather" you would typically be required to replace the entire cover.
I have never opened one up so I can't tell you how they are constructed. But I don't think there's really much to them other than a baffle that would stop any liquid oil droplets from traveling out to the intake with the crankcase gasses.
I'm not sure if anew one is available and if it is it's going to be expensive.

We just inspected them for any sort of blockage like a shop towel or other debris that may have gotten in there when it was off for other work.
That or maybe sludge from a very dirty engine or critter nesting in a vehicle that was stored or rarely used.
Other than that, there's not much to them unless it's maybe a bit of filtering media in there. I really don't know.
 
I have a 1999 130hp FI, I’m told this is the only Honda outboard with a pcv. They were made from 1998-about 2004 in a 115 or 130hp. I replaced mine, it was a car part.

I have no idea if this is the only Honda outboard with a pcv , just passing this on as an FTI.

Is your dipstick showing the oil level as normal?
 
FTI???
Is that transmittable???

( I know, I know....FYI)

Just couldn't resist and stop myself:)
 
Since did not find breather tube blockage or breather nipple, other things are too difficult for me, so I put everything together and plan to go to dealer tomorrow. Did one more run, to my surprise no more leak and exhaust looks good. I only took the air intake manifold and cylinder cover off, did not even touch dipstick seating. Also the oil level from dipstick looks ok. Hope it will last.
Thanks for all the help!
 
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