What would cause low oil pressure after about 10 mins? (Stumped .. again)

[BMANN06]

Hey all ... have the low oil pressure light coming on ... limp mode.

Started by replacing lower crank case OPS, no change, replaced the one up on top same result. I built a oil pressure gauge, (yes I was lazy in another post .. and I apolologize .. LOL) ... I can see oil pressure building up to around 50 psi on guage, then after about 10 minutes of driving oil pressure drops to about 25 psi and stays there. Can someone help me ... before I park this damn boat on a railway crossing and make an epic youtube video out of it. k sorry for being pissy its just annoying ... little history ...

This is an 04' sportser 4tec, recently rebuilt motor (bout 80% through break in), after the rebuild I took the boat for its maiden breakin .. didn't see this problem come up, but at same time engine didn't see much past 3000rpm. Sold the boat, new owner said breaking it in he could do (which I shouldn't have done .. he doesn't understand "BREAK IN"). Since ... I had to replace the pump and impeller as a result of new owner staring in in a pile of rocks. Since I'm not sure that this problem was there/or not before sale I feel I should fix it.

The fact I see the guage build to around 50 psi tells me the oil pump isn't cooked (sweet) ... what would cause oil pressure to build up to 50 psi and then drop ... regulator??? Any help is super appreciated!!! I'd like to get this guy his boat back by next weekend .. if I don't reply fast its because my wifey has dragged me somewhere ...

As usual THANKS A TON!!!!

 

[griz400]

does the light come on from the get go ??? after it warms up oil pressure will drop, but 25 psi should be ok, what is the spec ???

 

[griz400]

http://www.seadooforum.com/showthread.php?25570-oil-pressure-question

 

[BMANN06]

Hey Griz thanks for chiming in .. 25 psi is normal for around idle .. but it should jump a bit when your +5000rpm which it does. The first time anyway ... after pressure peaks and you back off throttle RPMS .. it drops and stays there. Which kinda tells me theres some regulator thats got issues ... I just dont know how this regulator works ...

 

[griz400]

i read a couple other posts from other places, and they are talking about what dennis said in the post i attached fromhere, like a new, different part number oil pressure switch, they say seadoo had a problem with the original part number switch, also, make sure you have the proper weight oil in it

 

[BMANN06]

Help is super appreciated!!

I have confirmed with a ohmetter that the switch is funtional. I can see infinite ohms when engine is off, then at idle minimal change in resistance but as RPMS get up past 4K see around 3 ohms. I was totally thinking it was at faulty oil pressure swtich, but wanted to confirm so got an oil pressure guage in place of oil pressure switch (shorted the OPS lead to ground to alleivate the low oil pressure alarm and limp mode) when using the the gauge I can see that at startup oil pressure is normal, when I climb through RPMs I can see on gauge oil pressure is building approx 50 psi, then for some reason when you drop the throttle RPMS back to say like 3000 or maybe idle. I can not see the oil pressure building ... just has me freakin stumped. There has to be a regualor of somekind that has issues .. I'm totally in the weeds on this one.

 

[thor7000]

just a shot in the dark here...had a similar issue on one of my bike race engines, would be fine at first then oil pressure would drop off. Turned out it was a bad oil pressure relief which would not close 100% therefore not allowing pressure to build. Don't know if the 4TEC's have them or not

 

[Dennis]

Sounds like the pressure regulator is sticking to me too. It's located at the rt. rear of the engine in the rear engine cover. All the way in the bottom of the cover. Look in the parts diagram under magneto. It's items 9,10,11 and 12. You don't have to pull the rear cover to access it but you'll have to remove the driveshaft and jack the back of the engine up pretty high. That's in a jet ski. Maybe a boat will be easier. I've seen them stick before and cause this problem. I've also seen oil filters collapse and do the same thing but was usually after the oil got mixed with water and created a mud. :cheers:

 

[BMANN06]

Ahhh ... there it is .. thanks dennis. I did change the oil filter as a "Shot in the Dark" I didn't see anything to worrysome in the filter usual minimal small filiments of metal from general break ins but no collapsing. I'll pull the regulator and take a look at what shape its in. This engine did sit for about a year and half dissassembled in a dealerhsip so it's probably worth replacing.

 

[BMANN06]

Could they have honestly stuck this part in a more annoying spot to service ... really.

 

[Dennis]

Yea, you're probably supposed to pull the rear cover to access it but that's not an easy job either!!

 

[BMANN06]

Update .. solved. Definately the piston on the oil pressure regulator. It was scored pretty bad.

You won't believe the headache this job was though. You know when working with aluminum threads, as soon as you crack the threadlock seal they pretty much just roll out. Not with this one! I could tell when pulling out the old regulator I was in trouble. Whomever put this in cross threaded the S"""" out of it.

Had to dump the coolant an pull the whole FN' mag housing off to fix the threads on the oil pump regulator. Why wouldn't BRP machine the mag cover so it could come off without having to remove the engine mounts ... do they no realize how simple some service wouold be ... maybe get one of the engineers to be a tech for one day!!!!

Anyways problem is solved ... what a fun boat!!!

Thanks again for all the help!!

 

[Dennis]

Glad it's fixed! Don't ya just love working on this stuff? uke:

 

[BMANN06]

Thanks Dennis .. is this going back to another thread you were helping me on were you were saying something like..

Well look at at the stuff you've learned!! :willy_nilly:

I hope not!! Cheers bro .. thanks for all the help!!!

:thumbsup: