2004 F115 Low oil pressure

[TownsendsFJR1300]

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

Please read the above thread. (I now have access to a F115 Yamaha manual).

The reference to the F150 and other engine was because Rodbolt indicated the relief valve was in one of those area's initially, THAT's why I posted those pic's, to help LOCATE the valve. Doesn't take a brain surgeon to know their completly different engines. Never said they were..

The oil relief valve is now believed to be in the oil pump (agreed).
Its NOT shown or mentioned in the shop manual and you won't find the relief valve available on ANY parts fisch.

The low oil pressure alarm light is activating and is verified by a mechanical gauge showing low pressure.

I don't need ANY manual to know there's an issue there, that's common sense..The system is telling you there's low oil pressure, its confirmed, mechanically and compared to an adjacent, identical engine (15-20 PSI vs 70 or so PSI)

Most oil filters have a by pass valve built inside as well even if the the filter clogs up (I assume the yamaha filter has the same).

*Bottom line, what needs to be done/replaced, etc (that already hasn't been done) to fix the oil pressure? Your thoughts?

[TownsendsFJR1300]

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.

I keep agreeing with you, the engines are not related, NEVER said they were... Please move on..


To beat a dead horse once more, the low oil pressure light activates (maybe a malfunction), fine..

Its been verified with a mechanical gauge as being LOW. He's getting 15-20 PSI at idle vs the other engine, 70PSI at idle.

**Once again, what would be the fix be, knowing the strainer is clean, etc (a certain part replacement, perhaps replace the oil pump altogether, especially if the relief valve is located inside it and not replacable, servicable?)

My thought, even if the relief valve is stuck open, it'll build pressure, just not bleed it off as designed at higher RPM's.

The oil pump itself, just worn out? I don't know how the OP measured the clearances inside (obviously very critical).



Heck, its not even my engine, just hate to see an engine, this far broke down, with a potential easy fix (oil pump?)

[BIGELOW-]

ALREADY REPLACED OIL PUMP (new OEM yammy pump) , did that when I pulled it all apart.. and Replaced oil filter twice No light- remember I said I have crappy gauges-


Engine runs liked a rape ape (good), hitting 43-44 mph GPS WOT @ 6000 RPM (thats pretty good for a twin 115 on polar 23/24/ft deep v)- If alarm wasn't sounding/ limp mode I'd be happily running around with low oil pressure and blistfully unaware my engine could blow at any moment LOL

Alarm was what got me witch hunting (motor runs great till alarm goes off, which puts it in limp mode)-
Troubleshooting- It is def low oil pressure (see posts above)-

Replaced/ Inspected everything below powerhead

MY GUESS- -It is either bad clearance somewhere in power head, or pressure relief valve which NO ONE can find ( unless its in oil pump, which is new, so prob rules that out.)

But I'm just a lowly non-mechanic that is pretty good at troubleshooting and taking stuff apart and putting back together...

I appreciate all the effort all of you have put forth in trying to solve my issue

[TownsendsFJR1300]

Bigelow... If its going into limp mode you should check/find out what is doing this. Not good.

You should/would pick up a hard code on the YDS (I would think) ,which will tell you exactly what is putting it in limp mode IMO.

Not familiar what the YDS would tell you on your particular engines to be honest.

If the YDS doesn't show why the engine is going in limp mode (with a hard code - for sure - which is your low oil pressure), maybe someone else can tell you on this forum.

Low oil pressure would certainly send it into limp mode. Did you mention "limp mode" early on in this post? I must have missed it.

While there may not be any/much of a comparison, on two of my F225s when the OPSers went off and failed, the engine never went into limp mode - but some mechanics said it should have.

I replaced the OPSers and have never had any of my engines go into limp mode with the faulty OPS .. before or after - knock on wood.

I'm at 600 hours on 3 F225s

Could be your OP switch (when it goes "on") is defective and sending false signal to EMM sending into limp mode.. just a wild guess. I'm not a mechanic. Just a Yammie lover...

I personally think you probably have two good running engines .. both with good oil pressures. Wanna bet (Rodbolt)?

JUST WANTED TO ADD. Congrats on getting it apart and back together AND RUNNING. Really. That's an accomplishment.

Thanks for the update on the pump, etc, clears that up.

And yes, very much an acomplishment for a "backyard mechainic"!!!!

Captsolo. He still has a mechanical oil pressure gauge showing 15-20 PSI @ idle (not good/normal) and of course going into limp mode (or at least dropping RPM's)

[TownsendsFJR1300]

Townsends... I question his reading of the oil pressure with his guage. What about that stupid on/off OP switch. Was it ever replaced with a new one? Was it ever changed from the good engine to the other good engine (i.e., the one he worked on and removed everything on)? Seems like a (THAT) bad op switch would sound the alarm on both engines sending them both into limp mode. He could test this out easily by switching the OP switch (whereeverthehellitis) between his TWO engines.

Dunno... I just PM'ed him, I know he's reading (obviously) on this thread and responding.

Agreed, something that can't hurt to check if it hasn't already been done.


I'm just curious as heck as to the issue.

Worse case, run it till it blows, it'll be real easy to find the issue then.. Gotta get it past that limp mode (could always "hotwire"/by pass it, I wouldn't, but its possible)

[BIGELOW-]

Come on fellas, give me a little credit.

1) I ran it on oil pressure gauge - watching... dropped to 15-20 psi at idle ( running out on water).

2)No alarm- obviously because I have the OPS unhooked and the mechanical gauge in the hole the ops goes in - OPS can't send ON signal to trigger alarm/limp.

3) Unhook mechanical gauge, put sensor ( ONE WIRE, slip on connector) back in.... run till alarm/ limp mode- always when coming off plane, when oil pressure drops

4)Walk back to engine, unhook the one wire to ops- alarm/limp quits and engine runs great (unhooking the wire tells the alarm the switch is off- all good (artificially)

5) but still has low oil pressure, cause it does every time I hook up gauge.

6) Gauge is not faulty b/cause test other engine in exactly the same manner and have above spec pressure ( spec on f115 is approx. 49 psi warmed at idle.

goes without saying, oil pressure alarm is linked to limp mode as a precaution against blowing engine

[BIGELOW-]

Quote by capt solo """""I personally think you probably have two good running engines .. both with good oil pressures. Wanna bet (Rodbolt)?"""

AND " I question his reading of the oil pressure with his guage.""


Goodness.... YES I WILL TAKE THAT BET- I do have two good running engines- FOR THE TIME BEING, one of the good running engines just happens to have pitifully poor oil pressure-

And I have a freaking DOCTORATE DEGREE- I can read an oil pressure gauge- I can also build a house from the ground up, and have built /welded farm machinery from raw steel stock- I have replaced/rebuilt about any mechanical device imaginable- Just using common sense. I am, however new to four stroke outboards, but I have owned at least 100 boats- I have 10 in my yard right now.

at least townsends gets it - quote to Capt solo "Captsolo. He still has a mechanical oil pressure gauge showing 15-20 PSI @ idle (not good/normal) and of course going into limp mode (or at least dropping RPM's) "

I do have two good running engines- FOR THE TIME BEING, one of the good running engines just happens to have pitifully poor oil pressure-

Townsends- No need to hotwire (bypass the OPS) all you have to do is unhook the wire, and it can't send the ON signal to the alarm

Similar to a 225 Mercury 2 stroke I had, when water fuel separator buzzer went off 10 miles out, I would unhook the one wire till I got in and replaced so I didn't have to hear the buzzer all the way in

Not trying to be rude capt solo, but u basically called me a dumbass

[rodbolt17]

this aint rocket science.
I DONT have a doctorate degree yet I spent over 8 years rebuilding auto engines, got to do the 455 in my 70 w-30 442 a few times.
18 yrs old with a 455,4spd and 3.90 posi isn't a good combo.
then it was on to about 6 yrs programming and setting up CNC lathes and mills at GOEX in Cleburne TX.
then it was on to 6 yrs in the USN's advanced electronics program.
then it was back to working on outboards and sterndrives which is about all I havedone since 1992.


you either have a faulty pressure regulating device, a warped oil pan, or excessive clearance someplace.

the basic design of the block and reciprocating assy has been around since about 1910.
nothing new here.

biggest difference between a 1955 265 chebby and your F115 is the chebby's used separate main bearing caps and the F115 has them cast in the crankcase cover.

[TownsendsFJR1300]

Come on fellas, give me a little credit.

1) I ran it on oil pressure gauge - watching... dropped to 15-20 psi at idle ( running out on water).

2)No alarm- obviously because I have the OPS unhooked and the mechanical gauge in the hole the ops goes in - OPS can't send ON signal to trigger alarm/limp.

3) Unhook mechanical gauge, put sensor ( ONE WIRE, slip on connector) back in.... run till alarm/ limp mode- always when coming off plane, when oil pressure drops

4)Walk back to engine, unhook the one wire to ops- alarm/limp quits and engine runs great (unhooking the wire tells the alarm the switch is off- all good (artificially)

5) but still has low oil pressure, cause it does every time I hook up gauge.

6) Gauge is not faulty b/cause test other engine in exactly the same manner and have above spec pressure ( spec on f115 is approx. 49 psi warmed at idle.

goes without saying, oil pressure alarm is linked to limp mode as a precaution against blowing engine

As that relief valve is apparently inside the oil pump, which is NEW, it rules that out. Agreed, the alarm is activating as its designed, due to actual, low oil pressure.

Sorry if the pic's I posted confused anyone(99Yam40), just trying to find that relief valve that NO ONE can find... I didn't have a pic of the F115 and its not shown in the Yamaha shop manual or parts fisch either (unlike the other engines pictured)


BTW BIGELOW, I give you MUCH CREDIT for digging this deep, quickly, without EVER having that engine apart nor having ANY experiance on that particular model, EVER...

**Now, if the PROBLEM itself could be found without the drama (which is what this forum is for) would be great!

Scott

[BIGELOW-]

Capt solo... yep, that's next step- Putting heavier oil I, especially since I'm in Florida and have 100 degree temps...

I have even thought about swapping the power heads from engine to engine.... that would isolate/confirm the problem to the power head (as opposed to possible warped pan issue (unlikely)).

I'm gonna run it 30 miles out this weekend. Wish me luck!!!

SeaTOW!!!!

Again, thanks for all the help.

[BIGELOW-]

UPDATE

I put 10w-40 oil in, no increase in oil pressure I could tell.

May 30th 2014 (last fri.) me and my son took the boat out 30 miles, caught about 130 pounds of snapper and red grouper- I ran out on both engines- I always just idled w/ good(starboard) engine cause at idle is when port drops pressure. Of course I had the OPS out, with mechanical gauge in the hole so I could keep an eye on oil pressure... Roundtrip was about 70 miles, no issues what so ever

June 1, 2014- Red snapper opener- Ran to the same hole above w me and 3 buddies- limited out on red snapper, gouple grouper. NO ISSUES other than keeping my fingers crossed and glancing at the crappy oil pressure every once in a while.

SUMMARY- Oil pressure is low, but after about 150 miles plowing through the sea, the old yammy is still running !!! No knocks, so i'm gonna keep pushing my luck HAHAHHA

[TownsendsFJR1300]

Now I'm hungrey!

[BIGELOW-]

HAHA- Couple years ago I hit the Salmon run in Alaska, shipped back 50 pounds of filets on the plane w/ me... maybe I can ship u some snapper- HAHAH

By the way, even though the engine ran great, the oil pressure gauge only showed about 25 pounds of pressure at 4500 RPM after it had beeen ran awhile... I Guess that's enough- It didn't blow and isn't knocking.

[BIGELOW-]

Almost a year later... gonna push my luck and try to fish this season ( boat hasn't been run except a couple times over the winter to circulate the fuel)... Engine is still running fine w/ low oil pressure.

I have been keeping an eye out for a powerhead/used F115 reasonably priced...If anyone knows where one is my email is bigelowrtt@yahoo.com

I should have taken the powerhead apart over the winter to see if I can fix the problem (bearings??).. I have no clue where to start though

[Nautical]

Try using a heavy weight oil additive like lucas oil treatment. If it improves your pressure you have a worn engine ..start at the bearings like you propose.