F300 Making Oil
#1
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I know this is an old subject. I have been reading old threads about this all morning but I have not seen any thing about thermostats making oil. Here is the situation.
i have a F300, 2018. From the day I took delivery of the boat, after the initial 10 hrs, at WOT I could barely get 5300 rpm. After going around for months with the dealer they finally put a lower pitch prop on allowing me to hit 5700 at WOT. I HAD 170 hrs on it by then. I was concerned about this as I heard all the stories about these engines making oil if not broken in hard and run hard. I have not had any issues other than the rpms. I just hit 220 hrs. The boat is going in for the 200 hr service Monday. I checked pil yesterday and it has filled to just below the high fill mark. It was mid point t weeks ago. I can smell gas on the stick.
so now I am concerned the rings are not seated properly. However the dealer said that it is probably caused by faulty thermostats. I have never heard that before. They explained that it the thermostats stick open keeping the engine from staying at operating temp the computer starts to add gas running a richer mixture to compensate. That allows for gas blow by to the oil.
Has any one heard this before?
i have a F300, 2018. From the day I took delivery of the boat, after the initial 10 hrs, at WOT I could barely get 5300 rpm. After going around for months with the dealer they finally put a lower pitch prop on allowing me to hit 5700 at WOT. I HAD 170 hrs on it by then. I was concerned about this as I heard all the stories about these engines making oil if not broken in hard and run hard. I have not had any issues other than the rpms. I just hit 220 hrs. The boat is going in for the 200 hr service Monday. I checked pil yesterday and it has filled to just below the high fill mark. It was mid point t weeks ago. I can smell gas on the stick.
so now I am concerned the rings are not seated properly. However the dealer said that it is probably caused by faulty thermostats. I have never heard that before. They explained that it the thermostats stick open keeping the engine from staying at operating temp the computer starts to add gas running a richer mixture to compensate. That allows for gas blow by to the oil.
Has any one heard this before?
#2
Senior Member

An engine that is running cooler than normal will be more prone to making oil than if it is running at a higher temperature. Thermostat(s) sticking open can be part of the problem.
In other models/brands a thermostat with a higher operating temperature was one element of a possible solution for the making oil phenomenon.
In other models/brands a thermostat with a higher operating temperature was one element of a possible solution for the making oil phenomenon.
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#3
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Sticking T-Stats on a brand new motor? Whatever.. have the dealer change them out. Running colder than operating can cause issues but let the dealer change them out, and change the oil since it's not your fault the t'stats "failed", then hit the motor hard and seat the rings.
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#4

I know this is an old subject. I have been reading old threads about this all morning but I have not seen any thing about thermostats making oil. Here is the situation.
i have a F300, 2018. From the day I took delivery of the boat, after the initial 10 hrs, at WOT I could barely get 5300 rpm. After going around for months with the dealer they finally put a lower pitch prop on allowing me to hit 5700 at WOT. I HAD 170 hrs on it by then. I was concerned about this as I heard all the stories about these engines making oil if not broken in hard and run hard. I have not had any issues other than the rpms. I just hit 220 hrs. The boat is going in for the 200 hr service Monday. I checked pil yesterday and it has filled to just below the high fill mark. It was mid point t weeks ago. I can smell gas on the stick.
so now I am concerned the rings are not seated properly. However the dealer said that it is probably caused by faulty thermostats. I have never heard that before. They explained that it the thermostats stick open keeping the engine from staying at operating temp the computer starts to add gas running a richer mixture to compensate. That allows for gas blow by to the oil.
Has any one heard this before?
i have a F300, 2018. From the day I took delivery of the boat, after the initial 10 hrs, at WOT I could barely get 5300 rpm. After going around for months with the dealer they finally put a lower pitch prop on allowing me to hit 5700 at WOT. I HAD 170 hrs on it by then. I was concerned about this as I heard all the stories about these engines making oil if not broken in hard and run hard. I have not had any issues other than the rpms. I just hit 220 hrs. The boat is going in for the 200 hr service Monday. I checked pil yesterday and it has filled to just below the high fill mark. It was mid point t weeks ago. I can smell gas on the stick.
so now I am concerned the rings are not seated properly. However the dealer said that it is probably caused by faulty thermostats. I have never heard that before. They explained that it the thermostats stick open keeping the engine from staying at operating temp the computer starts to add gas running a richer mixture to compensate. That allows for gas blow by to the oil.
Has any one heard this before?
#6
Senior Member


let them change the thermostats out if they want to. It'll make them feel better and you'll have brand new thermostats.
Then, once you change the oil, go out and run the living piss out of the boat.
When you've put 5-10 hours of good hard running on her and you see your oil at a normal level, sit back and enjoy the boat.
You may also want to check your engine height to ensure that it is not too low. 5700rpm is fine. 5900-6000 is mo' betta.
Then, once you change the oil, go out and run the living piss out of the boat.
When you've put 5-10 hours of good hard running on her and you see your oil at a normal level, sit back and enjoy the boat.
You may also want to check your engine height to ensure that it is not too low. 5700rpm is fine. 5900-6000 is mo' betta.
#7
Senior Member

Anyway, Yamaha does not specify which propeller by brand, model or pitch is to be used on any particular boat or motor for any particular user.
The motor does not have a propeller on or with it when it is delivered. If the motor had a propeller on it when the boat was shipped to the dealer then Hurricane Boats selected and installed the propeller. If the propeller was installed at the dealer by the dealer then the dealer selected which propeller to install.
The Performance Bulletin for your particular model with a Yamaha F300 installed indicates that a 15 3/4 X 15" SWS II propeller was used. Propellers used in PB test are almost always not the correct propeller for a boat and motor that has been placed into service. Reason being that PB boats are the lightest they will ever be. Add weight to the boat and a different propeller is needed. It would not surprise me if a 15 3/4 X 13" SWS II propeller would be more appropriate.
#9
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I agree the PB may not be correct. But it should be the starting point. In my case the PB for my boat was using my boat exactly except I have bottom paint. They put a 17P on because Yamaha was back ordered on the 15P. The dealer argued that 5300 was within the 5000-6000 range of the engine. The boat operated great except I know OB engines thrive on running hard. I finally called Yamaha and while they danced around the fact that 5300 is OK they finally acknowledged that the F300 should be 57-5900 at WOT for optimum performance. I agree I could drop a pitch but I am OK with the 5700.
#10
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If you have a digital temp gauge your looking for 145 degrees. Long runs around 145 degrees helps seat the rings.
If you dont have a temp gauge that gives an actual number they make an adapter cable to hook to your fishfinder.
If you dont have a temp gauge that gives an actual number they make an adapter cable to hook to your fishfinder.
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I know this is an old subject. I have been reading old threads about this all morning but I have not seen any thing about thermostats making oil. Here is the situation.
i have a F300, 2018. From the day I took delivery of the boat, after the initial 10 hrs, at WOT I could barely get 5300 rpm. After going around for months with the dealer they finally put a lower pitch prop on allowing me to hit 5700 at WOT. I HAD 170 hrs on it by then. I was concerned about this as I heard all the stories about these engines making oil if not broken in hard and run hard. I have not had any issues other than the rpms. I just hit 220 hrs. The boat is going in for the 200 hr service Monday. I checked pil yesterday and it has filled to just below the high fill mark. It was mid point t weeks ago. I can smell gas on the stick.
so now I am concerned the rings are not seated properly. However the dealer said that it is probably caused by faulty thermostats. I have never heard that before. They explained that it the thermostats stick open keeping the engine from staying at operating temp the computer starts to add gas running a richer mixture to compensate. That allows for gas blow by to the oil.
Has any one heard this before?
i have a F300, 2018. From the day I took delivery of the boat, after the initial 10 hrs, at WOT I could barely get 5300 rpm. After going around for months with the dealer they finally put a lower pitch prop on allowing me to hit 5700 at WOT. I HAD 170 hrs on it by then. I was concerned about this as I heard all the stories about these engines making oil if not broken in hard and run hard. I have not had any issues other than the rpms. I just hit 220 hrs. The boat is going in for the 200 hr service Monday. I checked pil yesterday and it has filled to just below the high fill mark. It was mid point t weeks ago. I can smell gas on the stick.
so now I am concerned the rings are not seated properly. However the dealer said that it is probably caused by faulty thermostats. I have never heard that before. They explained that it the thermostats stick open keeping the engine from staying at operating temp the computer starts to add gas running a richer mixture to compensate. That allows for gas blow by to the oil.
Has any one heard this before?
#12
Senior Member

At 200 plus hrs you're unlikely to induce much at all other than high fuel burn with hard running, the opportunity to seat rings has likely passed.
Thermostat function can influence oil dilution in these engines, that is fact despite HT expert opinion to the contrsry. Let dealer swap them out. May be alternative temp range available, I am not sure on this.
During run in, it's not *running the piss out of them* that seats piston rings perse', it's more a function of engine load., less than engine speed. Vary load throughout the operating range at sympathetic engine speeds for the first few hours, avoiding sustained low engine speed and load is the genuine proven best method. After a few hours, "normal" operation is the go, again, emphasising varying engine speeds, with occassional limited bursts to Wot, not sustained. Variation. Load. Correctly propped to reach the upper end of the recommended engine speed range in light ship trim.
The oil dilution issue is not a Yamaha issue, it's wider spread than that across the manufacturers.
In your case, continually "running the piss* out of your engine will likely demonstrate a reduction in oil dilution by raising operating temps enough to evap off enough crank case accumulated fuel to reduce overall oil volume. That may make you feel better without changing the core issue.
Thermostat change will be worthwhile, and possibly look at altering oil viscosity, this may help.
Good luck,
Thermostat function can influence oil dilution in these engines, that is fact despite HT expert opinion to the contrsry. Let dealer swap them out. May be alternative temp range available, I am not sure on this.
During run in, it's not *running the piss out of them* that seats piston rings perse', it's more a function of engine load., less than engine speed. Vary load throughout the operating range at sympathetic engine speeds for the first few hours, avoiding sustained low engine speed and load is the genuine proven best method. After a few hours, "normal" operation is the go, again, emphasising varying engine speeds, with occassional limited bursts to Wot, not sustained. Variation. Load. Correctly propped to reach the upper end of the recommended engine speed range in light ship trim.
The oil dilution issue is not a Yamaha issue, it's wider spread than that across the manufacturers.
In your case, continually "running the piss* out of your engine will likely demonstrate a reduction in oil dilution by raising operating temps enough to evap off enough crank case accumulated fuel to reduce overall oil volume. That may make you feel better without changing the core issue.
Thermostat change will be worthwhile, and possibly look at altering oil viscosity, this may help.
Good luck,
#13
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I was between 100 and 150 hours when I went "balls to the wall" with my 225 SHO. Whether it was pressure, temperature, rpms, engine load or just cloudy weather, I did probably three 25 mile, one way, long runs at greater than 5000 rpms, with a good bit of that at 5500 and above before mine quit the "making oil" business. I would estimate that I was running the engine like that over a 30 hour period, before it quit making oil.
#14
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Despite the fact that nobody is claiming that the thermostats can never be the issue, nor the claim that it's only a Yamaha problem, I'll stand by my recommendation to run the piss out of them. See, running the piss out of them is merely a saying. It means many things, up to and including the wide variation of rpm. Running the engines hard (i.e. - running the piss out of them) doesn't automatically mean that one should run them wide open for hours on end. That'd be foolish and would only hurt your wallet via the gas pump. But a good hard running, putting the engines under load, repeatedly, will assist in seating the rings.
By saying that one should run the piss out of the engines is merely saying that one shouldn't just idle along, then get on plane and hum along at 4000rpm.
I do agree that 170 hours is a little late to try to rectify this through seating of the rings. Describing the actual break in procedure does nothing at this point as we are well past the need to stay under certain rpm for certain hours and so on. When I had this same issue with multiple Yamaha motors and a Suzuki, it was detected within the first 100 hours or so. I then ran the piss out of them and never experienced the problem again.
If you don't want to run the piss out of them, then try running the shit out of them. Either way, make the motor do some work.
By saying that one should run the piss out of the engines is merely saying that one shouldn't just idle along, then get on plane and hum along at 4000rpm.
I do agree that 170 hours is a little late to try to rectify this through seating of the rings. Describing the actual break in procedure does nothing at this point as we are well past the need to stay under certain rpm for certain hours and so on. When I had this same issue with multiple Yamaha motors and a Suzuki, it was detected within the first 100 hours or so. I then ran the piss out of them and never experienced the problem again.
If you don't want to run the piss out of them, then try running the shit out of them. Either way, make the motor do some work.
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#15
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An independent Yamaha tech advised this. He said that after I get the oil changed and the thermostats changed (he believes they are the most likely problem) to run the boat at just below planing. In other words plow the water, for about 30 minutes. This puts the maximum load on the engine and rings and will seat the rings properly. He says that while running the piss out of them heats the rings and helps seat them, it is at maximum load on the engine that actually seats the rings. Any opinions on that?
#16
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An independent Yamaha tech advised this. He said that after I get the oil changed and the thermostats changed (he believes they are the most likely problem) to run the boat at just below planing. In other words plow the water, for about 30 minutes. This puts the maximum load on the engine and rings and will seat the rings properly. He says that while running the piss out of them heats the rings and helps seat them, it is at maximum load on the engine that actually seats the rings. Any opinions on that?
When mine had the same issue, I never changed the thermostats. Seems odd that they'd be bad on a one year old 170 hour engine. I mean, seems like a good scapegoat, for sure, because they "could" be a cause, but there's enough of these motors (and other brands) with the making oil problem that you gotta be pretty gullible to think that ALL of these brand new engines have bad thermostats.
#17
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I think on a nice day we outa take your boat and head about 35 miles offshore to my favorite fishing hole. Two hours running at 5,000 rpms may work wonders. And I believe Alloyboy is correct in the assertion you need a 13 pitch prop. When I went from 19 pitch to 17 pitch the performance difference was remarkable.
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I think on a nice day we outa take your boat and head about 35 miles offshore to my favorite fishing hole. Two hours running at 5,000 rpms may work wonders. And I believe Alloyboy is correct in the assertion you need a 13 pitch prop. When I went from 19 pitch to 17 pitch the performance difference was remarkable.