Introduction and lots of questions

[Pas Bon F115]

Hi all. First time on this site. I use the other sites but seldom get a response hope this is a more active site so here goes.

2001 Yamaha F115 200 hours.

1.) Checked the oil and it is way overfull. I suspect the sinister "making oil" syndrome has struck so I pull the thermostat ad WA LA!! Thermostat stuck wide open. I have ordered a replacement.

Do you think this is 100% of the cause of getting extra fluid in my crank case?

2.) Independent of the above issue, should I preemptively service the VST since I am around 200 hours and 12 years old? or should I wait till I have an issue? I have been religious about keeping good fuel and fuel treatment in it and it has always run very well.

Any 200 hour service suggestions?

Thanks!!!

[boscoe99]

I can't surmise that the thermostat being stuck open is 100% the cause of your problem but a stuck thermostat is known to cause, or contribute to, the making oil issue. Put the new one in and see what happens.

On a 12/13 year old motor I would change the VST filter just for the hell of it. I might also go so far as to remove the injectors and send them out to be tested and cleaned.

Other stuff to do

water pump r and r and grease the drive shaft splines while you are at it
gear oil r and r
motor oil r and r
fuel filter r and r
timing belt r and r
check plugs and replace if needed
inspect for corrosion
check the anodes

Is this a saltwater or freshwater usage motor? Have you owned the motor since new or did you get it used?

[Pas Bon F115]

Thanks Bascoe!

I am the original owner

I plan on doing the basics, all the oil and spark plugs as well as the fuel filters ( I also have a spin on 10-micron)

Timing belt? yep probably need to look in to that.

Fuel injectors....might as well yank em if I service the VST

Water pump got swapped out a couple of years ago, but I'm sure it wouldn't hurt.

I have read about a busted diaphragm in the fuel pump cause fuel to enter the crankcase, does that apply to fuel injected models and if so how do I check for that?

[jackmanjls]

PBF115, I went through my F90TLR last yr and had the fuel injectors cleaned. The guy did a great job and was reasonable. If you email me at jackmanjls@gmail.com I will send the injectors guys name. I'm reluctant to post his name on this forum...I don't know if they allow that.

[99yam40]

putting your e mail on here is not a very smart thing to do

Spammers can get a hold of it too easy
Private Messages is the best way to go.
that way it is not up for everyone to see

[rodbolt17]

a ruptured/leaking pump diaphragm can and will make oil.
so will overpropping an EFI 4 stroke.

[Pas Bon F115]

a ruptured/leaking pump diaphragm can and will make oil.
so will overpropping an EFI 4 stroke.

Thanks!

I am positive I am NOT over-propped.

How to you detect/test for an issue with the diaphragm?

[Pas Bon F115]

.....Looking at the diagram in my service manual I see two fuel pump diaphragms, one is about $2 bucks the other is about $40. I guess I could take the pump apart and inspect it?