2004 F115 Low oil pressure

[TownsendsFJR1300]

Any O-rings in the oiling system look flattened loosing oil pressure?

Were you able to check spec's with a feeler gauge on the pump itself?

65.3 lbs at idle is spec for the F150 so 72 lbs is in the ball park.

NOW, besides the oil filters being on other sides, I did see the "OIL RELIEF VALVE" (page 1-13 yamaha F150 shop manual). See bottom picture.

Its located inbetween the oil filter bracket and the actual oil pump. Same page show oil flow from the oil pan TO strainer TO oil pump TO RELIEF VALVE TO oil filter bracket TO oil filter, etc. Cannot find it anywhere for the F115



Found it on the F350, in between the pump and filter bracket(part #16):
http://www.boats.net/parts/search/Ya...PAN/parts.html




__________________________________________________ ______________________________________


For the F150, part #34:

http://www.boats.net/parts/search/Ya...201/parts.html

[BIGELOW-]

Goodness, those schematics give me a headache...LOL.

I did replace all the O-rings- Just in case......

The oil pump itself has a brass "plug looking thing", kinda resembles a freeze plug on a engine block- maybe designed to blow if pressure gets too high??

Thanks townsends, I will research the F150 a little more and see if I can see what you are referring to, maybe the F115 is the same...

[TownsendsFJR1300]

Goodness, those schematics give me a headache...LOL.

I did replace all the O-rings- Just in case......

The oil pump itself has a brass "plug looking thing", kinda resembles a freeze plug on a engine block- maybe designed to blow if pressure gets too high??

Thanks townsends, I will research the F150 a little more and see if I can see what you are referring to, maybe the F115 is the same...

Is it in the same general area as the above parts fisch's? Should have some sort of hole in it with probably a SS ball with a spring behind it. (Guestamating again). Fixing to look in the F115 manual..

[TownsendsFJR1300]

Looked in the service manual for the F115 and didn't see any pressure relief valve.

Per the "troubleshooting section", low oil pressure issues are (1) the oil pump or(2) oil filter, period. No mention of the pressure relief valve.

Rodbolt, with the F150 and F350 parts fisches above, any idea where the valve is?

[rodbolt17]

the F150 its located under the block, the F350 under the powerhead adapter.
the F115 I think its part of the pump and not serviced seperatly.
kinda like an old chevy oil pump.

I have not done a powerhead or pump on an F115 in 4-5 years.
I am doing an F350 powerhead now.

[TownsendsFJR1300]

the F150 its located under the block, the F350 under the powerhead adapter.
the F115 I think its part of the pump and not serviced seperatly.
kinda like an old chevy oil pump.

I have not done a powerhead or pump on an F115 in 4-5 years.
I am doing an F350 powerhead now.

Thanks, that would make sense...

[BIGELOW-]

Thanks for all the effort/help guys.... It was my first time pulling a 4 stroke powerhead and completely dissembling the midsection- I learned a lot

Well, since I replaced pump w/ new yammy pump, screen on pickup was clean, the only thing left is an internal power head issue..... Wish there was a happy ending, but not this time

Like I mentioned before, engine has 40-60 #'s oil pressure when running and 20# s at idle... I'm gonna run it till it starts knocking then replace powerhead.

I'll let ya'll know when it blows!!! HAHAH

Anyone know where to get a good powerhead reasonable??

[TownsendsFJR1300]

Thanks for all the effort/help guys.... It was my first time pulling a 4 stroke powerhead and completely dissembling the midsection- I learned a lot

Well, since I replaced pump w/ new yammy pump, screen on pickup was clean, the only thing left is an internal power head issue..... Wish there was a happy ending, but not this time

Like I mentioned before, engine has 40-60 #'s oil pressure when running and 20# s at idle... I'm gonna run it till it starts knocking then replace powerhead.

I'll let ya'll know when it blows!!! HAHAH

Anyone know where to get a good powerhead reasonable??

Didn't know you had other internal issues.

If you have bearing gone south, that would explain any knocking obviously and possibly the oil pressure (too much clearance from whatever bearing went south).

Something else to try to see about the rod bearings, without much time into it, rotate the crank until piston # X starts to go DOWN (mid stroke).
Then, take a screwdriver (or shaft) and push DOWN on the piston(thru the spark plug hole). If there's lots of play in the rod bearing(s), you'll FEEL IT MOVE while the crank remains stationary.

Heck your this far, I'd be pulling it apart and checking for the issue. Labor is the big part and you have that covered..

[BIGELOW-]

I don't have any known powerhead issues, I'm just assuming it has to be that (checked everything else). There is no knocking, no whining/screaming, no metal in pan/shiny oil- nothing to indicate a powerhead issue, plus the compression is 180 evenly across the cylinders

I will attempt the pushing on piston, but pretty sure if it moves like that a compression test would indicate an issue. I think I remember that cyl 1 and 4 fire/stroke together and 2&3 fire together

[TownsendsFJR1300]

I don't have any known powerhead issues, I'm just assuming it has to be that (checked everything else). There is no knocking, no whining/screaming, no metal in pan/shiny oil- nothing to indicate a powerhead issue, plus the compression is 180 evenly across the cylinders

I will attempt the pushing on piston, but pretty sure if it moves like that a compression test would indicate an issue. I think I remember that cyl 1 and 4 fire/stroke together and 2&3 fire together

Agreed, there must be something inside bleeding off oil pressure. A bad rod bearing wouldn't make a dirrene on a leak down test or compression test. the pistons still going up and down, rings still working... Something likely with the crank or ?

Anyway, post how it goes if you fix or blow up!

[TownsendsFJR1300]

Townsend.. The 72 psi was on his other (good) engine not the one he took apart. Check Bigelow's original information/post.

I'm wondering how well it ran before Big took it all apart? Was it missing? Did it just have low oil pressure and an alarm?

That first post is what I'm referencing from and the spec's (PSI) from my F150.

Being it was a recovered stolen boat/engine, it was likely beat on. A rod knock is usually easy enough to hear, a main bearing, not so much... He mentioned no knocks or unusual noises.

I think just super low oil pressure verified with a mechanical gauge is the issue. To be at 15 vs 72, either the oil pump is worn inside (we know the pick up is clear), or its bleeding off badly inside the engine (the big unknown) somewhere in the oiling system.

BTW, was the oil filter ever changed out(not sure if that would even make a difference-blocked up, not allowing oil thru)

[rodbolt17]

and here again we are going to start some internet myths that will never go away.

good intentions, totally clueless.

other than OIL, the F115 and the F150 AND F225, share NOTHING in common.

nice that other posters try to share, QUIT.

the old F115 has a simple ON/OFF switch.\
just like the one on your fridge or bedroom light.

[TownsendsFJR1300]

and here again we are going to start some internet myths that will never go away.

good intentions, totally clueless.

other than OIL, the F115 and the F150 AND F225, share NOTHING in common.

nice that other posters try to share, QUIT.

the old F115 has a simple ON/OFF switch.\
just like the one on your fridge or bedroom light.

Clueless?? What myths?? You serious??

I think you missed his first post. His oil alarm light was on. Oil pressure (or lack of) was verified by a mechanical gauge at 15 PSI or so, NOT 70 PSI @ idle..

OIL PRESSURE IS OIL PRESSURE, I don't care what engine it, Yamaha F350, F115, F150 or car engine, etc.. That's common sense..

Forget the model, an engine is an engine, That "on/off" oil switch is set to activate at (and IT IS ACTIVATING).

Are you stating that the light is wrong, 15 PSI is normal for idle? Disregard the warning light?

The F115 Yamaha manual shows a relief valve opening at 69 PSI but doesn't note where it is, nor is it in any parts fisch, so yes, it likely has to be part of the Oil pump and not a purchasable separate unit..


*The bottom line is low oil pressure, verified by a mechanical gauge, the warning light as well. PSI at idle well below the adjacent engine..

Your suggestion (experiance) on what to check / change out to remedy the issue?

[99yam40]

this thread is for a 115 but you keep putting in specs for a non 115 is one thing that is a problem.

And stating that an oil filter could restrict oil flow and cause low oil pressure in a motor is probably what Rodbolt was referring to about the new myth.
I have never heard of any motor that had all of the oil flowed through the filter. It is and always was a small side stream to the filter and could never restrict oil flow and pressure to the motor. Think about it why would they engineer something that would wreck a motor because the filter got plugged

[rodbolt17]

not disputing the verified lack of correct oil pressure on that F115.

what I am getting at is other than oil and an 8D paint code the F115,F150 and the F225 share NOTHING oil related.

the F150 and up motors use an ECU map.
its mapped for oil pressure sensor feed back voltage VS engine RPM.
the TWO MUST match or the alarm is set.
the F115 uses a simple ON or freaking OFF switch.

the F150 and up motors can throw a code/alarm for under or over pressure at any given RPM.
the F115 cannot.
the F115 can only throw a code for lack of pressure.
but somewhere on the F115 there must be a method to regulate oil pressure.
like I said its a positive displacement pump,a trochoid design.
faster you spin it the more pressure it can make.
it must maintain a minimum pressure at 600 RPM yet not blow the filter apart at 6000 RPM.