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2017 BF90D making oil

D

deanno33

New member
Hello,
I just purchased a lightly used Lund Impact 1675 with a BF90D. Although I haven't verified, the guy I purchased the boat from said the engine has about 50 hours on it. From the looks of everything, I do believe that to be close. When I got the boat home I checked the dipstick and the oil level was really high. I drained the oil, refilled (4.4 qts), measured just at the second dot (tad under). Also change oil filter. The oil was darker but no milk color. Some little brownish bubbles though. I also smelled fuel (I believe). I then took the boat out yesterday for the first time and it ran perfectly. I was on the water about 3 hours and had the boat running at multiple idles for about 40 min. Got home and checked the dipstick, high again and I smell gas.

Read alot last night and some say the thermostats could be the cause. I pulled the block and head therms and hot water tested, both worked fine. I am ordering new ones and swap them out just to eliminate that from the mix. I also have new spark plugs to put in and plan on doing that as well.

Any other advice? I read that maybe you should use a higher temp thermostat so the engine can heat higher? Her are my part numbers.

19300-ZW9-003 – Block Thermostat 60 degrees Celsius
19300-ZY6-003 – Head Thermostat 50 degrees Celsius

Makes me nervous that running the boat for less than an hour, my oil level went from the top dot on the dipstick to almost an inch above the top dot.

Thank you everyone!
 
Hi,
First off, I'm not the resident expert on these and haven't worked on a Honda EFI outboard. My opinions are just general knowledge.

Yes, that would make me nervous too!

It sounds like this outboard has done a lot of sitting and that can take a toll on some components.
I would be suspicious of the low pressure fuel pump or injectors sticking for this.

The pump, being cam driven, will deliver fuel directly into the oil if it's leaking.

The injectors on the other hand, if sticking open, will leak fuel to the cylinder and into the crankcase when the engine shuts down. Yes maybe while it's running too but usually when it's not.

Since you say it runs well and doesn't smoke, I would say the pump is your likely culprit.

The tstats are also prime candidates if stuck open and the engine runs cold but that contamination usually takes weeks or months, not hours/days simply because it's due to incomplete combustion letting fuel rich vapors get by the rings.

Good luck.
 
jgmo said:
The pump, being cam driven, will deliver fuel directly into the oil if it's leaking.

The tstats are also prime candidates if stuck open and the engine runs cold but that contamination usually takes weeks or months, not hours/days simply because it's due to incomplete combustion letting fuel rich vapors get by the rings.

Good luck.
Click to expand...
Is there a way to check to see if the fuel pump is leaking?

Thermostats were both closed when I pulled them. Dropped into hot water and both opened, then closed when removed from the water.

No place around me has a fuel pump or the thermostats. I just ordered OE parts on ebay so hopefully I can get some items swapped out by the weekend.

Thank you for the help!
 
Again, I don't work on these...

But I have thought about how I would check a pump for leaking and, after considering the hassle involved, and the pump not being super expensive, I believe I would just swap it out if I thought it was causing this issue.

Testing it would involve making up a jig, (metal or even wood might do) that you could bolt it to and then hold in a vice. You would then need to connect it to a fuel source. I figured I would just use a primer hose connected to a portable tank without the quick disconnect and plumb it directly to the pump input.

The tricky part is what to do about the pump outlet. I think you might get away with simply hooking up a section of hose and just putting it back into the fuel tank filler spout.

Then squeeze the bulb and get fuel to flow looking for leaks. If none then you might get someone to pump the primer while you pushed the pump plunger in by hand.

Finally, you would need to block off the end of the delivery hose to "deadhead" the pump outlet and push the plunger against that resistance and see what happens. Easy huh?

That's why I say I might just fire the parts cannon on this one. At $130 + shipping I think I'd let the wallet do the work.

See items 22 and 23 in the link below.

Honda Outboard 90HP OEM Parts Diagram for FUEL PUMP | Boats.net

Buy OEM Parts for Honda Outboard 90HP FUEL PUMP Diagram
www.boats.net www.boats.net

Note that 2 are listed so no matter where you source one, you need to make sure that you're buying the correct part number for your engine's serial number.

While it may be possible to pull the valve cover, disable the ignition and injectors and simply crank it looking for fuel leaking I'm not confident that you might see much. The pump's lifter is directly below the cam sprocket so it wouldn't be easy to see. And, it's going to make a big mess.

Again, this is all speculation on my part so don't take anything I'm telling you as gospel. Just "brainstorming" with you hoping that you can find a cause for "making oil".
 
deanno33 said:
Hello,
I just purchased a lightly used Lund Impact 1675 with a BF90D. Although I haven't verified, the guy I purchased the boat from said the engine has about 50 hours on it. From the looks of everything, I do believe that to be close. When I got the boat home I checked the dipstick and the oil level was really high. I drained the oil, refilled (4.4 qts), measured just at the second dot (tad under). Also change oil filter. The oil was darker but no milk color. Some little brownish bubbles though. I also smelled fuel (I believe). I then took the boat out yesterday for the first time and it ran perfectly. I was on the water about 3 hours and had the boat running at multiple idles for about 40 min. Got home and checked the dipstick, high again and I smell gas.

Read alot last night and some say the thermostats could be the cause. I pulled the block and head therms and hot water tested, both worked fine. I am ordering new ones and swap them out just to eliminate that from the mix. I also have new spark plugs to put in and plan on doing that as well.

Any other advice? I read that maybe you should use a higher temp thermostat so the engine can heat higher? Her are my part numbers.

19300-ZW9-003 – Block Thermostat 60 degrees Celsius
19300-ZY6-003 – Head Thermostat 50 degrees Celsius

Makes me nervous that running the boat for less than an hour, my oil level went from the top dot on the dipstick to almost an inch above the top dot.

Thank you everyone!
Click to expand...
deanno33, I had the same problem with my 225 several years ago. Turned out it was running to cold and fuel was getting past the rings. Replaced the thermostats and problem went away. Hope this helps. RJ.
 
Assuming this is my SN since it's all I see on the motor I will order the fuel pump now.

New thermostats are ordered.

Thank you everyone. Appreciate the insight!

20230619_162246.jpg
 
The first link I sent you was directing to order the pump by the ENGINE serial number....
Not the outboard VIN number.

The VIN and ENGINE serial numbers are not the same.

The ENGINE serial number is typically located on a MUCH smaller label at the front of the engine block near the base.

Yours being a 2017 year model, I would think that the old number...06167-ZY9-000 would have been superceded by the later issued
16700-ZY9-013....

I don't know about you but that is confusing to me.

I suggest that you find your ENGINE serial number and make sure you're ordering the pump that matches that.

Or, you might want to phone a BIG city BIG Honda dealer parts department and ask them.

Good luck.
 
I looked all over that engine and base. All I see is what I posted earlier. Based on that number and knowing it's a BF90DK4, I think 06167-ZY9-000 is the correct part. Unless like you mentioned, it was replaced by a newer part number. So confusing.
 
Found the S/N on some hidden papers. BBCJ 1303428

Now to line that up with the other numbers and hopefully get a match for the fuel pump.
 
I'm such an idiot. It was late and I was on my way to bed when I posted that I found the S/N on some paperwork last night. It's the same number I posted previously stamped into that plate. So, really it was nothing new and what I have below is all I should need.

Model BF90DK4
S/N - BBCJ 1303428

1687261512896.png


Once again, thank you. I would have no doubt ordered the wrong part. Once I get everyone done this weekend, I will try it out and report back.
 
Just curious, did you happen to measure how much oil you drained out? I have the same 2017 90 Honda as you and have noticed the same high oil level, about a 1/2 inch above the full line. Oil is clean and can’t smell any gas,
 
Good question. I planned to, but unknown to me, my oil pan had a crack. I had oil all over my garage floor. Good thing we have a cat.

I did measure carefully when I refilled the oil and verified on the dipstick where the level was. Then after using the boat once, noticed the level was a good 3/4 inch above the second dot.
 
Where does your VST vent. line discharge go? If your float is allowing too much fuel into the VST is it possible that the extra fuel is getting pushed out he vent line into the crankcase? A common problem on a Suzuki, maybe something similar is happening to you? Full disclosure: I’ve never worked on in EFI Honda outboard and may be out in left field on this.
 
William01 said:
Where does your VST vent. line discharge go? If your float is allowing too much fuel into the VST is it possible that the extra fuel is getting pushed out he vent line into the crankcase? A common problem on a Suzuki, maybe something similar is happening to you? Full disclosure: I’ve never worked on in EFI Honda outboard and may be out in left field on this.
Click to expand...
Hey William01. I'm not sure but I can remove the lower c
1000001582.jpg
owling and take a look. I'm certainly not a mechanic but am figuring things out.

On a different note, I just pulled the fuel pump as my new one arrived today. There is oil coming from the pump area? That can't be right. Here's a pic.
 
First off I have never worked on a Honda I was merely tossing out an idea of why you might be getting fuel in your oil. Having oil behind your mechanical fuel pump doesn’t surprise me since it’s driven by the camshaft which is lubricated by engine oil. Check the old pump’s diaphragm for holes, good light and possibly a magnifying glass. That rubber diaphragm is all that keeps the fuel out of the engine.
 
Also, the one gal jug of Yamalube I am using shows 4L. The 4qt line is at top of my finger in pic. If accurate, 4 L is actually 4.22 qt which means I may have overfilled this last time....just thinking there was 4 qts in the jug.
1000001583.jpg
 
William01 said:
First off I have never worked on a Honda I was merely tossing out an idea of why you might be getting fuel in your oil. Having oil behind your mechanical fuel pump doesn’t surprise me since it’s driven by the camshaft which is lubricated by engine oil. Check the old pump’s diaphragm for holes, good light and possibly a magnifying glass. That rubber diaphragm is all that keeps the fuel out of the engine.
Click to expand...
I really appreciate the help! Sincerely. Like mentioned, I'm handy but not a mechanic so trying to figure this stuff out with the help of more knowledgeable people.

The oil jug does have me a little confused. The label states 1 gallon, 3785 ML. The actual markings on the jug show 4 L which would be 1.057 gal or 4.22 qts.

When I changed the oil last week I poured the entire gal in and then just over half of another qt. Based on that, I may have overfilled it myself, not realizing it...at approx 4.8 qts.

I'm draining the oil now and will be careful watching the dipstick when refilling.

I changed both thermostats, both fuel filters, spark plugs and fuel pump.
 
It can be frustrating, BRP a Canadian company sells their oil in 946ml bottles yet the manual calls for 2 litres so until recently you had to buy 3 bottles for an oil change. Now when you buy their oil change kit you get 2 jugs of 946ml and a smaller jug of 100ish ml to make up the difference. I’m guessing BRP oil is coming from the US. Got to read the labels and do the math.

When I change oil I shoot for half way between the add and full mark then check, run the engine recheck immediately after shut down, let it sit so the oil can drain back into the crankcase then recheck. Once the boat is in the water I repeat the above again.
 
deanno33 said:
Hello,
I just purchased a lightly used Lund Impact 1675 with a BF90D. Although I haven't verified, the guy I purchased the boat from said the engine has about 50 hours on it. From the looks of everything, I do believe that to be close. When I got the boat home I checked the dipstick and the oil level was really high. I drained the oil, refilled (4.4 qts), measured just at the second dot (tad under). Also change oil filter. The oil was darker but no milk color. Some little brownish bubbles though. I also smelled fuel (I believe). I then took the boat out yesterday for the first time and it ran perfectly. I was on the water about 3 hours and had the boat running at multiple idles for about 40 min. Got home and checked the dipstick, high again and I smell gas.

Read alot last night and some say the thermostats could be the cause. I pulled the block and head therms and hot water tested, both worked fine. I am ordering new ones and swap them out just to eliminate that from the mix. I also have new spark plugs to put in and plan on doing that as well.

Any other advice? I read that maybe you should use a higher temp thermostat so the engine can heat higher? Her are my part numbers.

19300-ZW9-003 – Block Thermostat 60 degrees Celsius
19300-ZY6-003 – Head Thermostat 50 degrees Celsius

Makes me nervous that running the boat for less than an hour, my oil level went from the top dot on the dipstick to almost an inch above the top dot.

Thank you everyone!
Click to expand...

deanno33 said:
Hello,
I just purchased a lightly used Lund Impact 1675 with a BF90D. Although I haven't verified, the guy I purchased the boat from said the engine has about 50 hours on it. From the looks of everything, I do believe that to be close. When I got the boat home I checked the dipstick and the oil level was really high. I drained the oil, refilled (4.4 qts), measured just at the second dot (tad under). Also change oil filter. The oil was darker but no milk color. Some little brownish bubbles though. I also smelled fuel (I believe). I then took the boat out yesterday for the first time and it ran perfectly. I was on the water about 3 hours and had the boat running at multiple idles for about 40 min. Got home and checked the dipstick, high again and I smell gas.

Read alot last night and some say the thermostats could be the cause. I pulled the block and head therms and hot water tested, both worked fine. I am ordering new ones and swap them out just to eliminate that from the mix. I also have new spark plugs to put in and plan on doing that as well.

Any other advice? I read that maybe you should use a higher temp thermostat so the engine can heat higher? Her are my part numbers.

19300-ZW9-003 – Block Thermostat 60 degrees Celsius
19300-ZY6-003 – Head Thermostat 50 degrees Celsius

Makes me nervous that running the boat for less than an hour, my oil level went from the top dot on the dipstick to almost an inch above the top dot.

Thank you everyone!
Click to expand...
Hey deanno33. I know it’s an old thread but I’m having the same issue with my 2019 bf90 Honda. Did you ever find out what the problem was with your engine? Thanks.
 
deanno33 said:
Hello,
I just purchased a lightly used Lund Impact 1675 with a BF90D. Although I haven't verified, the guy I purchased the boat from said the engine has about 50 hours on it. From the looks of everything, I do believe that to be close. When I got the boat home I checked the dipstick and the oil level was really high. I drained the oil, refilled (4.4 qts), measured just at the second dot (tad under). Also change oil filter. The oil was darker but no milk color. Some little brownish bubbles though. I also smelled fuel (I believe). I then took the boat out yesterday for the first time and it ran perfectly. I was on the water about 3 hours and had the boat running at multiple idles for about 40 min. Got home and checked the dipstick, high again and I smell gas.

Read alot last night and some say the thermostats could be the cause. I pulled the block and head therms and hot water tested, both worked fine. I am ordering new ones and swap them out just to eliminate that from the mix. I also have new spark plugs to put in and plan on doing that as well.

Any other advice? I read that maybe you should use a higher temp thermostat so the engine can heat higher? Her are my part numbers.

19300-ZW9-003 – Block Thermostat 60 degrees Celsius
19300-ZY6-003 – Head Thermostat 50 degrees Celsius

Makes me nervous that running the boat for less than an hour, my oil level went from the top dot on the dipstick to almost an inch above the top dot.

Thank you everyone!
Click to expand...
Hellow. I know this is an old post by was wondering if you ever solved your issue with fuel in the oil? I have a 2019 bf90 Honda with the extract problem. I change the fuel pump and hotter thermostat and also a head gasket and still have fuel going into the engine.
 
Hmmmm. Never updated with a fix.

Just my opinion....
....and, I've never worked on a Honda 90D but there are a few things that could cause this problem.

1. Stuck open thermostats causing overly rich running. He replaced his.

2 faulty low pressure fuel pump leaking gas into the oil. He replaced that.

3. Faulty fuel pressure regulator allowing too much fuel from high pressure pump to enrichen the mixture.

4. Faulty/leaking fuel injector or injectors.

5. Faulty Oxygen sensor allowing an overly rich mixture

There are other things that might cause rich fueling and a "making oil" condition but those 5 are the main ones and most common IMO.

I'm guessing of course but, based on his report about how quickly the oil level rose and smelled like gasoline, I would say that it is MOST likely that the cause would be either 2 or 4. LP fuel pump or bad/leaking Injector(s).

Bad t-stats or malfunctioning O2 sensor would likely take at least a week or more to raise oil level.

A bad pressure regulator would probably take more than a day or two if not longer.

So, I suspect leaking Injector(s) or LP fuel pump because of the speed with which he said the oil level would rise.

I too would be interested in what he ultimately found. Too bad he hasn't reported back but it happens quite often that people never do.
 
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