MacGregorSailors.com

Hi all,
this is a question for the more mechanically inclined (which is not my expertise). My 2003 Honda 50hp 4 stroke engine has generally treated me very well over my 7 years of ownership. Last year I noticed the oil level was high when I was doing my routine check. I googled the issue and some other owners indicated that keeping your gas line connected in hot climates during long periods of storage may contribute to the problem (which I have done in the past). Anyhow after changing the oil and rechecking after nominal use last season (aproximatel 25 hours of runtime over 4 months) I noticed that my oil level was still increasing. I realize I probably need a honda mechanic to address this issue but would like to get some suggestions and ideas of what might be causing this issue before I take it into the shop.
I appreciate any insight.
Cheers
Kevin

Drain your oil and check for water. Remember oil floats. If you have an internal leak in the cooling system it could show up as a high oil level.

Also, be sure you're checking the oil after the same amount of time after shutdown. That filter will drain to the sump, but if it's cold it can take a little while. I've noticed my oil level going up and down a little until I realized I should be checking it cold, or after enough time that it's done draining.

I use a vacuum oil sucker to drain my motor oil, and the skinny tube down the dipstick tube gets pretty much all of it. Just a few drops come out the 'normal' drain plug and chute after using the pump, so I don't even bother with that any more. But if you do that, you can measure how much comes out when changing the oil (the plug and chute makes a big mess, so hard to measure) for comparison to how much you put in.

I also leave the fuel tank vents cracked so the hose doesn't build pressure and force its way into the engine, but I suppose what's after the check valve in the squeeze bulb could expand and be forced into the carbs and beyond.

Thanks Bob...i checked for that and their is no water or coolant in the oil...which makes me think it is gas mixed with the oil. The engine suprisingly runs fine.

is it otherwise running fine? My Yamaha was doing the same thing and after much troubleshooting I found an incorrect gasket in one of the carbs that was causing it to run rich and flood. Oil smelled like gas

4 Stroke O/B engines r known for making oil during long periods of trolling or running @ very slow speeds if it,s minimal , some guy,s on here who had this issue have said that giving the O/B Engine a good run @ W.O.T. usually cleaars it up !

On fuel injected engines if it is really bad & ur eng has a miss it,s likely an injector or broken internal fuel line , but as u say it,s running fine otherwise I,d give it a good run @ W.O.T. & if it,s due to excess idling it should burn off the excess oil
hope this helps & the other guy,s who had this issue can maybe chum in

J

There is no such thing as making oil. Your oil system is getting contaminated with somthing. Most likely fuel. 2003 model carbureted? A float needle leaking?

Tomfoolery wrote:Also, be sure you're checking the oil after the same amount of time after shutdown. That filter will drain to the sump, but if it's cold it can take a little while. I've noticed my oil level going up and down a little until I realized I should be checking it cold, or after enough time that it's done draining.

I use a vacuum oil sucker to drain my motor oil, and the skinny tube down the dipstick tube gets pretty much all of it. Just a few drops come out the 'normal' drain plug and chute after using the pump, so I don't even bother with that any more. But if you do that, you can measure how much comes out when changing the oil (the plug and chute makes a big mess, so hard to measure) for comparison to how much you put in.

I also leave the fuel tank vents cracked so the hose doesn't build pressure and force its way into the engine, but I suppose what's after the check valve in the squeeze bulb could expand and be forced into the carbs and beyond.

Do you have a link to the vacum oil sucker that you use Tom? I'm sure some work better than others.

I'm a HD mechanic. A few things will be bad enough to raise the oil level that much. First off though, water in oil will be make it turn milky and make tons of sludge, so we can eliminate that of the bat. A broken piston ring, broken exhaust valve rocker, a very deep scratch on your cylinder wall will cause fuel air mixture to end up in your crankcase. You will have a very high fuel consumption and decreased performance. But even so, your engine will sound and run like "normal". A 3 cylindre engine has an uncanny way of sounding normal when one cylindre is dead. But you should stop using your engine and investigate and fix it. With that much fuel in your oil, i guarandamnedtee you you're hurting your engine.

P.S. Oh and your fuel pump. When they go bad, they leak fuel in the crankcase on BF50's. And they go often from what i've heard. Still, DO NOT use your engine til you find the problem.

silverfox441 wrote:I'm a HD mechanic. A few things will be bad enough to raise the oil level that much. First off though, water in oil will be make it turn milky and make tons of sludge, so we can eliminate that of the bat. A broken piston ring, broken exhaust valve rocker, a very deep scratch on your cylinder wall will cause fuel air mixture to end up in your crankcase. You will have a very high fuel consumption and decreased performance. But even so, your engine will sound and run like "normal". A 3 cylindre engine has an uncanny way of sounding normal when one cylindre is dead. But you should stop using your engine and investigate and fix it. With that much fuel in your oil, i guarandamnedtee you you're hurting your engine.

Agree with above...In my past life was a CAT diesel tech, "making oil" is never a good thing if it is gas it may burn off on WOT but if it comes back there is an issue. Oil that is thinned out is hard on bearings whethe gas or water, with water being the worst. Could be an issue as listed above where unburned fuel is entering the base...which a compression test may find or could me a more direct source such as gasket, carbs etc is leaking into the base when engine is running or even off.

Not familiar with your engine directly but I had a 2005 Yamaha 4 stroke and the oil level remained stable all season. You could refer to this past post as it has some info that may be relevant as well.

http://www.macgregorsailors.com/forum/v ... =8&t=25853

Agree with all the above and would add you can always test some of the 'made' oil for around $40 at most CAT dealers. This will tell you for sure if it's gas or water (pretty easy to figure that one out really)but may also help identify where it is coming from and if there are more underlying issues (worn bearings, rings even etc) and save a bunch of money rather than having your mechanic just start troubleshooting or missing something that could or should be replaced while its apart or scrap the thing all together and start shipping for a new one.

mac n cheese wrote:Do you have a link to the vacum oil sucker that you use Tom? I'm sure some work better than others.

It's the Tempo Oil Boy, but I believe it's discontinued. Which is a shame, as it gets rave reviews, and it works as advertised. https://www.amazon.com/Tempo-Oil-Boy-Fl ... B0000BYP0L But West Marine has a shorter version, which should be adequate for an OB. Mine came with 3 sucker hoses of different sizes - you use the largest that will fit wherever it needs to go (dipstick tube, usually). I got it for an inboard diesel, which had no drain plug, so an oil sucker is the only way to get the oil out (common in small IB diesel auxiliaries).

https://www.westmarine.com/buy/west-mar ... ecordNum=1
https://www.westmarine.com/buy/west-mar ... ecordNum=2

Those vacuum pumps are brilliant for bleeding hydraulic brakes and a host of other jobs. Well worth the money. Makes bleeding brakes or flushing out the entire fluid system a breeze on your own.

Silverfox,
thanks so much for your suggestions. From my preliminary research I read the same thing about fuel pumps on the BF50. I have not noticed the fuel consumption being extra ordinarily worse but I have not really been monitoring it that closely (Frankly I use the engine pretty sparingly as I like to sail as much as possible)....that being said I have noticed somewhat of a lack of performance when I tried to get the boat up on plane last fall. I will definitely not run the motor until I have a honda mechanic look at this. Boat is on the hard right now in storage but in the next month I will take it over for service and I will be sure to let you know what I found out and if your assessment was correct.
Cheers and thanks for everyone's input! Much appreciated
Kasmith

grady wrote:There is no such thing as making oil. Your oil system is getting contaminated with somthing. Most likely fuel. 2003 model carbureted? A float needle leaking?

Hate to inform U that u are wrong "the term" Making Oil is used in the trade as describing a fluid leaking into the crankcase & therefore raising the oil level ! 'Thus using the term "Making Oil"

Also excess idling is well known in the trade to cause "makin oil" as unburned gas or deisel leaks down into the crankcase , same as excess idling a diesel eng in certain weather condintions can fill the crankcase with water "due to excess "moisture in the air created in the crankcase " forms into water as it cools down

J