slight gas in oil 2009 yamaha 4 stroke

[stevedan]

slight gas in oil 2009 yamaha 4 stroke any input

 

[boscoe99]

What model?
What is the usage pattern?
How is it propped?
What is the age?
How many hours?

 

[stevedan]

What model? TLR F150 HP 4 stroke
What is the usage pattern? light use
How is it propped? lowered with motor cover normally
What is the age? 2009
How many hours? no idea at this point, only had for about 5 months, working to get PMs done and notice smell of gas in oil and high level "above full"

 

[stevedan]

was thinking maybe fuel pumps leaking into crank case, ?

 

[stevedan]

sorry, prop is 14 1/2 x 23, S/S

 

[99yam40]

make sure the stats operate in spec., cold motor makes oil sometimes
slow running, idling, or trolling tends to make oil too

over propped does to I think. what RPM will it hit at WOT

 

[stevedan]

have only had the motor at around 4k to 4.5 K RPM
"34 to 38 MPH"

 

[stevedan]

just changed the stat with new spark plugs, but have not ran due to gas in oil etc.. was hoping to resolve before changing oil

 

[99yam40]

have only had the motor at around 4k to 4.5 K RPM
"34 to 38 MPH"

why?
was that all you could get out of it?

 

[stevedan]

why?
was that all you could get out of it?

No, just don't run it hard, having only had 2 strokes,, always kind of took it easy on them,. hoping to make them last !!

 

[stevedan]

2009 Yamaha 150 HP 4 stroke------Not getting a lot of feedback on this subject, but have continued to do some research on other sites. I certainly don't think I am the only person having this issue nor is OEM Yamaha jumping in anywhere to defend their product "imagine that". But from what I have gathered, "basically" if you don't have fuel pumps (lift pumps) leaking out the back into the crack case or a bad Thermostat then you are not running your motor hard enough to get the oil hot to prevent the fuel vapor from gathering, causing high oil level etc.. I hope this helps someone else and helps in reducing your time trying to find input / answers. If you get any additional information, please provide thank you!

 

[99yam40]

only way to know if you have the motor propped right is to run it WOT to see what RPM it gets too.
you do not have to keep running it hard tho

 

[stevedan]

that is on my todo list on my next outing, fresh oil change, new thermostat, new plugs with fingers crossed on this issue. Will update on my RPM at WOT. thanks so much for your feedback 99yam40, feedback is KING with owning a boat now of days!

 

[boscoe99]

was thinking maybe fuel pumps leaking into crank case, ?

That is one possibility.

 

[boscoe99]

have only had the motor at around 4k to 4.5 K RPM
"34 to 38 MPH"

Run the motor at wide open throttle (WOT) with the boat loaded. Engine trimmed up just to the point of best boat speed and no further. What is the WOT RPM?

 

[boscoe99]

2009 Yamaha 150 HP 4 stroke------Not getting a lot of feedback on this subject, but have continued to do some research on other sites. I certainly don't think I am the only person having this issue nor is OEM Yamaha jumping in anywhere to defend their product "imagine that". But from what I have gathered, "basically" if you don't have fuel pumps (lift pumps) leaking out the back into the crack case or a bad Thermostat then you are not running your motor hard enough to get the oil hot to prevent the fuel vapor from gathering, causing high oil level etc.. I hope this helps someone else and helps in reducing your time trying to find input / answers. If you get any additional information, please provide thank you!

You and other users of Mercury Marine, Suzuki, Yamaha, Honda, Tohatsu and Johnson four strokes have suffered from gasoline in the oil. Known as the engine "making oil".

There is nothing for Yamaha to defend. It is a characteristic of four stroke motors.

There are a number of events singularly, or together, that can cause a motor to make oil. As you note, camshaft driven lift pumps being just one. Thermostat(s) being stuck open. Extensive idling, cold water operations, too much propeller pitch being some others.

 

[stevedan]

You and other users of Mercury Marine, Suzuki, Yamaha, Honda, Tohatsu and Johnson four strokes have suffered from gasoline in the oil. Known as the engine "making oil".

There is nothing for Yamaha to defend. It is a characteristic of four stroke motors.

There are a number of events singularly, or together, that can cause a motor to make oil. As you note, camshaft driven lift pumps being just one. Thermostat(s) being stuck open. Extensive idling, cold water operations, too much propeller pitch being some others.

boscoe99 thank you for reply !!!----- it is my lack of knowledge and lack of experience with 4 stroke motors, guess the old 2 smokes were just to easy. I am hoping with the info I have gained, I can operate the motor correctly (WOT) and also ensure operation of all components "thermostat". And keep an eye on that dip stick. Will log the info on prop on my next outing, which I am hoping is this coming weekend, (waiting on parts for oil change / fuel filter/ fuel water separator filter) again thanks for the reply !!

 

[stevedan]

hey boscoe99, my numbers are 54 MPH at 5200 RPM. Had it trimmed up a lot,, could have gone more, but was porposing so I backed off. Thought I would have gotten more RPM out of the motor than that, 6200 is red Line on this gauge / motor.
let me know what you think.

 

[boscoe99]

A 2009 F150 has a red line RPM of 6000. You are over propped.

 

[Lou C]

You can have either fuel dilution or water dilution of the motor oil, or even both at the same time, to know which you have to do an oil analysis.
Fuel dilution is probably more likely to over-rich fuel issues, such as a carbed engine with a sticking float, choke not coming off when it should, or carb problems, injectors staying open or leaking, etc.
Water dilution is mostly due to the engine running too cold. For a 4 stroke engine, outboards run very cold, like 125-135*F which certainly is cool enough to get water dilution of the motor oil. Either one is bad, and I'd start with an oil analysis to find out exactly what's happening.
The interesting thing is that gasoline inboards, are also 4 stroke designs, yet water or fuel contamination is less common, unless you have a sticking choke not opening all the way or a sticking thermostat not closing all the way.
Also many late model inboard gas engines run a 160* stat so the run warmer, and the issue of water contamination is less likely....on mine I had a choice of a 140 or a 160 and even though I'm in salt water I use the 160, because when I tried the 140 it took forever to warm up and there was condensation in the exhaust system.