02 Mercury Pro XB 250 - OT430883
I have the intermittent 4 beep horn which im assuming is the low oil alarm. I put a new sending unit in engine oil tank, still does it, read on here to try to jump the sending unit wires, still does it. I loosened my engine oil tank cap (ended up taking it off completely) and no oil runs out of engine oil tank while running on hose, so obviously there is another issue. Any help would be greatly appreciated...
Check remote tank pickup screen, check caps to make sure they're tight, o-rings in place and caps seated properly.
Check for loose tie-wraps, or damage to hoses.
Inline oil filter could be clogged.
Crankcase Pressure Check Valve (or a reed on #6) could be bad.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Update on oil issue.
I put a new crankcase check valve in, still wont push oil to engine tank. I checked my pickup screen, its clean, I put new o rings in my remote tank, still wont push oil to tank. I checked all my hoses they look fine.
Don, I see you say something about a inline filter being clogged, i checked every inch of hoses, and dont see a filter? Where would / should it be?
Many engines have a small white filter inline (just inside the cowling) on the black w/blue stripe hose.
It will probably be best to get a hand-actuated gearcase pressure tester, and connect it to the solid BLACK line (that connects to the crankcase pressure check valve).
Pressurize the system to 6 psi and see if it holds. If it does NOT, put some soapy water in a spray bottle (or kiddie bubble mix) and start checking hoses, connections, caps, etc.
If it DOES hold 6 psi, loosen the engine mounted tank cap and see if it will bleed the air from the engine-mounted tank.
DOES hold pressure and DOES BLEED: Reed on #6 cylinder broken or not sealing, loss of compression on #6, faulty check valve.
DOES hold pressure and DOES NOT BLEED: Restriction between remote oil tank level and engine-mounted tank (black w/blue stripe hose and fittings).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Another update:
Pressured system up to 6psi at hose where it connects to the crank case check valve, and the system works as it should. It fills the engine tank, loosen cap a bit and oil comes out. And it will hold 6psi as long as you want it to.
I put a guage system i made on the check valve, which is new by the way and maybe 2lb at best. So next I will run a compression test, I did not long ago and all were good, If that checks out guess its time to do the reeds.
Don I had you put the TDR reeds in this thing and go through fuel system back in 2012, So we will see... May have to send it in again...
EAM,Originally Posted by EuropeanAM
Thank you Sir ! Excellent information, You've answered every possibility for me as well ! I'm in the same situation for the 2nd time in 3 months on my 2018 250xs with 300+ hours on it. Last time, I learned how this simple system worked, cleaned screen ( and entire tank), confirmed no leaks, replaced a restricted white check valve/filter, and because my dealer did not have a replacement I cleaned with brake cleaner and compressed air the engine mounted check valve. After maybe up to 5 minutes of idling in my yard, oil was flowing to the engine mounted oil tank, fixed. Just happened again this weekend. I will buy that engine check valve, check and or replace the other white filter/valve again, and expect all will be good again ( may need screen cleaned as well ). A couple more questions if I might Sir ?
- I'm told some Optimaxes came from Mercury with EFI oil in them and others with the brownish oil that I have in mine. Is it possible that this is an oil issue ? I did not have any issues like this on my EFI, ever.
- The better question that I would like to ask though, is- Am I "babying" my engine too much ? I use just enough power to get on plane and cruise around after that at about 40 mph in my 2018 Ranger 521L. At times, usually in tournaments I am really on it, wide open too. But 90% of the time, I'm cruising, especially with fuel prices these days. Should these motors be driven harder more, in order to have higher pressure in this system, possibly preventing clog ups ?
TIA !
~Tony
Glad the info was helpful. However- we need to keep posts to specifically to the engine of the Original Poster (so as to avoid confusion and/or Post-HiJacking).
Open your own separate thread if you would like to discuss your engine.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
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