2019 Yamaha F25 making oil

I now have almost 50 hours on my 2019 Yamaha F25 and it continues to make oil. After my first oil change I ran it for about 15 hours before checking it. The oil was past the full level and almost touching the rubber plug. I pumped out as much as I could without doing a complete oil change and filled back to to halfway mark with fresh Yamaha 10w 30 oil. I was told by my dealer to go out and run it WOT for two hours and see if that would seat the rings in. That didn’t work either, oil is back to full mark again after about 5-6 more hours. Any suggestions? Should I try a heavier oil? I worry about the gas diluting the oil and harming my engine.

I did my best to follow Yamah’s break in recommendations If anything I didn’t run it hard enough the first 10 hours.

Is there a oil check protocol?

LOL but on my 4 stroke Yamaha jet ski engine the level changes drastically from cold to hot.

Jet ski's run a dry sump system. Outboards are semi-dry sump, well sorta.

There are a ton of things that can cause oil level to rise. Do you idle a lot? Do you have happen to have a datalog from dealer inspection that I can look at? Specifically the number of total hours vs the number of hours at 0-1000 RPM, 1000-2000 RPM, then 4000-5000 and 5000-6000. Datalog will have all that in it and tells me how the motor is used and somewhat what the prop is doing.

What prop is on it? What is your maximum RPM?

What kind of usage does it see? Idle all the time in cold water or?

What kind of boat is it mounted on?

There is a possibility of the engine running rich but if that's the case, why? There's reasons for that too, and it'd be obviously running poorly. Do you have a photo of the spark plugs?

Frequent start/stop particularly before the engine ever gets hot will make oil too.

Is the oil milky at all?

What is the service history? What kind of oil, and what filter do you use?

I have the same motor, never makes oil, but I don't baby it either. Average usage, spends about 20% of it's time below 2000 RPM,50% 2000-5000, 20% 5000-6000 and a little bit over 6000 if I'm on the big lake outrunning a storm or something. Maxes out at 6180 or so with 11" prop showing right at 30mph GPS. I do change it somewhat often (about every 15 hours or so) but it's never over-full, never really changes other than it darkens up a little.

TurboTodd below are my responses to your questions. Thanks for your help.

I don't idle a lot but I do give my engine at least 3 minutes to warm up, preferably 5 minutes.

I don't have a data log but I could probably get one once things settle down with CV.

The prop is the standard factory aluminum prop, (11-1/4")

RPM range at WOT is 5800 to 5900. I installed a TinyTach to monitor the hours and RPMs. I run WOT when I can but the lake I fish is usually crowded with jet skis and pleasure boats so it makes it difficult to run fast. I would estimate my idle/half throttle/WOT at 20/40/40 percent.

I use my boat for fishing purposes on Lake Blackshear in Georgia. It is a shallow water lake and current surface temp is around 75 Deg.

My boat is a War Eagle 648 LDV with 21" transom

No pictures of the plugs but I can get them later

The oil is slightly dirty and thin, not milky. It does have the slight smell of gas.

I first changed the oil only at 18 hours and then changed it again at 22 hours with filter the second time. Both times I used Yamaha 10W 30 and second service I used the Yamaha oil filter. I have twice recently pumped out around 10-12 ounces of oil and replaced it with 8 ounces in fresh Yamaha 10W 30 oil. This puts it about 1/2 to 3/4 up the dip stick. I know I should probably take time to do a complete oil change but when it get over the high mark this is a quick way for me to get back on the water and chase the Crappie while the fishing is good.

Also my dealer told me to trim the boat down to make it work harder and run WOT for 2 hours to help seat the rings. I have trimmed it down slightly and run it WOT every chance I get but so far it hasn't helped.

Probably propped ok.

You NEED a dealer datalog (with ydis) to watch the engine temperature. My fear is that the thermostat isn't closing, engine temp stays cold.

Also need a complete oil change but you know that already.

does your hourmeter (tinytach) match the motor hours? Just curious, don't think it's got anything to do with the issues at hand.

There is a low pressure fuel pump on the back of the motor. It has a diaphragm in it. I haven't seen too many fail but it can; when it does it pours gasoline right into the crankcase. Worth a look. I usually pull them off, leave the lines attached and then depress the button several times after cleaning the oil off of it. If it's leaking, you'll see fuel.

TurboTodd,
I think the engine temp is ok. After running it for a few minutes I took the cowling off and placed my hand on the side of the engine. It was pretty warm. Not blistering hot but not a place you would want to leave your hand for very long.

I am in the process of changing the oil but I only have 30 ounces of Yamaha 4 stroke oil left. Is it ok to top it off (approx 4 ounces) with Quicksilver Premium 4 stroke oil? Nearest Yamaha dealer is 1 hour away.

I put the TinyTach on my motor after about 2 hours of break in. It currently is reading 48 hours.

I also pulled one of the plugs and it had a off white color to it.

The low pressure fuel pump may be something I need to have looked at or is that something that I could do myself?

Thanks!

nah, the LP fuel pump is easy enough to remove. 10mm wrench and 10mm socket.

You might consider a valve adjustment. Removal of the LP pump is part of removal of the valve cover, you'll be right there anyway. No gasket, just an o-ring. Set 'em to spec. I think 005-009 intake and 008-011 exhaust (double check me).

The only other thing I can think of would be the fuel pressure regulator. I havent' had the cowling off of mine in ages but a lot of the EFI motors have a regulator that has a vacuum hose going to it. If the internal diaphragm of the regulator fails it will allow fuel to pass into the vacuum hose, which contaminates the intake charge with fuel, causing engine to run a little rich. Just a shot in the dark.

If it is under warranty I would not be wrenching on it. Take your findings back to the dealer & ask him to drain the oil & have it analysed for gas contamination. Maybe you will have to pay for the lab test but then you will have their attention.

It is under warranty and I do plan on taking it in for a check up this week. I don't need to be buying parts when I could have the dealer install them under warranty. At first I thought the fuel pump wouldn't cost but a few bucks that's not the case anymore.

After doing another complete oil change last week and running the motor on the hose for a few minutes to make sure the oil was well circulated the level wound up being just below the 1/2 mark. I took it back out to the lake to run the motor some (WOT as much as possible) and put 1 hour and 10 minutes on it. I checked the oil today and now the level is all the way up to the full line. That didn't take long.

Just curious how you're checking the oil? Ideally, check it before you start the engine, and after it sits for a minimum of 30 minutes (preferably overnight) after being run. Should be in the checkered region of the stick not at the top. I kinda think you're doing it right but wanted to be sure.

I give the oil at least an hour or so to settle before I check it, then I check again the next day. I also make sure the motor is in the same position (motor tilt and trailer height) each time I check it.

This past week the lake was very calm and not many boats were out. I took advantage of it and ran the boat WOT from for a little over 1 hour without slowing down. Now my motor seems to have stopped making oil, it may have even dropped slightly from the high point (if that's possible). It is holding steady at just over the 3/4 mark on the last three fishing trips.

Keeping my fingers crossed that it has corrected itself. Maybe I just didn't run it hard enough during break in.

blackshear said:

I give the oil at least an hour or so to settle before I check it, then I check again the next day. I also make sure the motor is in the same position (motor tilt and trailer height) each time I check it.

This past week the lake was very calm and not many boats were out. I took advantage of it and ran the boat WOT from for a little over 1 hour without slowing down. Now my motor seems to have stopped making oil, it may have even dropped slightly from the high point (if that's possible). It is holding steady at just over the 3/4 mark on the last three fishing trips.

Keeping my fingers crossed that it has corrected itself. Maybe I just didn't run it hard enough during break in.

Click to expand...

It could have dropped a little due to a new oil filter (if installed).

My last oil change was w/o oil filter. I ran the motor on the hose for about 5 minutes and let the oil settle before checking it, which was just below the half way mark. After running it for a couple of hours on the lake the oil level moved up to all most touching the high mark, it stayed there for a couple of outings. I finally got a calm day last week was able to run it WOT for over an hour without slowing down for pleasure boaters etc. When I got home the oil level appeared to have dropped slightly to just over the 3/4 mark and has been holding steady at that level for the last few trips. I put another hour on the engine just yesterday and the oil level is still at the same location of slightly over 3/4. I'm thinking maybe i should change the oil one more time to be sure I don't have contaminated oil.

I agree with the oil change.

Please keep us up to date with what you are seeing.

I changed my oil a couple times during the break-in period for my new Suzuki in 2018.
The oil level rose like you described after idling and some light throttle the first hour in a barrel. I would never do this again.
Anyway, after running out on the lake, it was never a issue again. Happy boating!

Blackshear, is your oil level still showing good? Do you mind posting what the recommended Yamaha break-in is for this motor and how closely you adhered to that?

I'm going to look at a new F25 at the dealer Wednesday and am beginning to lean towards it vs the Tohatsu 25. I've only broke in a couple of outboards following rebuilds and both were 2 strokes and I really only varied the throttle the first couple hours and from then on out drove em like I stole them haha. But being this will be my first ever brand new outboard purchase and dealing with a factory warranty, I want to do it correctly.

Not blackshear, but...

I have a 2017 F25SWHC, this is the break in procedure:

https://www.manualslib.com/manual/654603/Yamaha-F25c.html?page=50#manual

I followed it closely and "made" a good amount of oil in the 1st few hours. I changed the oil after I noticed the issue and ran as hard as possible
(while following the recommended procedure)
for the the remainder of the break in & had no further issues.

I ran full synthetic oil on my 2nd change, & made
oil again. Switched back to conventional oil & haven't had an issue since. Currently at 60ish
hours ( I do 20ish hours a year).

kdgrills said:

Not blackshear, but...

I have a 2017 F25SWHC, this is the break in procedure:

https://www.manualslib.com/manual/654603/Yamaha-F25c.html?page=50#manual

I followed it closely and "made" a good amount of oil in the 1st few hours. I changed the oil after I noticed the issue and ran as hard as possible
(while following the recommended procedure)
for the the remainder of the break in & had no further issues.

I ran full synthetic oil on my 2nd change, & made
oil again. Switched back to conventional oil & haven't had an issue since. Currently at 60ish
hours ( I do 20ish hours a year).

Click to expand...

Thanks!

I was able to pick up one myself yesterday. The dealer set it up and briefly ran it and then I checked the oil today and it was exactly halfway between the low and high ranges. I ran it in a barrel for about ten minutes while I set up my inductive tach but that’s all. I’ll follow the recommended break in and just monitor the level carefully. Hopefully I can get the first couple of hours logged tomorrow So I can open it up and see how it does!