Back at it with another repair on the Optimax. This should be the final issue (I hope). Crankcase air check valve for oil system. Parts from www.boats.net Part Number: 8781051 - cylinder block check valve $29.21
Steve, I feel your pain. I’ve got a 2013 Merc 250 Pro XS and have dealing with this very problem for a few weeks now. I replaced the small oil tank on the engine thinking it was the float/magnet on the sensor. A lot of YT videos and forums on line said that was a common problem. I noticed the oil was half full in the small tank so I started going through the system. I changed the inline oil filter ahead of the small tank, cleaned the strainer on the bottom of the pickup tube in the remote reservoir. Pressurized the system with an air compressor and I it filled the small tank. Took the boat out on three different days and on the third day got the low oil alarm again. Went through the system again and replaced the check valve and the o-rings on the remote oil reservoir. Went fishing after that on four different occasions. No problem for three days and thought is was fixed but on the fourth trip out got the low oil alarm again. Went through the oil system again today. I pressurized the system and sprayed a soapy water solution on all the lines and fittings. Had a tiny leak on one of the caps on the remote reservoir, tightened the cap up and stopped that. I replaced the zip ties Mercury uses for hose clamps on either end of the air line from the check valve to the remote reservoir with steel hose clamps. I started up the engine to check for air pressure coming off the engine. That checked out OK. Have to take it to the lake and run it to see if the problem is fixed or not. Very frustrating because it’s such a simple system. Thanks for making the videos. Hopefully your problem is fixed. Keep up the good work.
My screen on the oil pickup was getting slimy and not allowing oil flow. I rinsed it with gas and a toothbrush, changed the oil for fresh and got rid or the low oil alarm. Now I'm having issues with rpm loss at takoff and high speed running. My 2004 200 OPTIMAX is a strong running engine when in shape. It's kind of hard to trust right now in SE Alaska waters.
I had that same issue with the slimy oil and pick up tube. Cleaned it out and used new oil and running great. Sorry to hear about the low rpm issue. Not sure what causes that. Good luck.
Clear lake Tx? I can’t find anyone to work on mine around here. If not a 4 stroke they won’t touch it. I started straining my oil. I’ve found even using the recommended oil it’s clumpy in the bottle. No more issues since. I want to get my poppets replaced also so any direction of where to go will be appreciated.
That sucks… just found your ch….my 90 opti has run like a Swiss watch for 13 yrs… it’s an 05 … bought used, love it … reliable as can be for myself .. like the vids
I’m dealing with the same thing, I’m about to replace the check valve on mine this weekend. I’m not getting oil up to the top oil reservoir on the engine on my 1990 200 mercury.
Check the pickup tube in the remote tank. If it has some sludge on the screen, you may have some bad oil that coagulates and plugs the screen. That’s what happened to me. We replaced the tube, cleaned the tank and put in fresh oil. That appeared to solve the issue. Only time will tell.
I ended up taking all the oil and running it through a filter, then replaced all the o rings/pick up and hoses/check valve. One of the rubber grommets for the oil/air manifold was ripped and must have been causing the issue. I plan on replacing everything else during the winter when the highschool bass season is on break
problem with techs today is that if softweare cant fix it, they are totally lost . diagnostic skills are gone ,most dont know what it takes for an internal combustion engine needs to run correctly.but sounds like you found a tech that may have skills ,keep this persdon on speed dial
If you pressure tested the tank with the cap on that, should have checked the check valve. I have heard that the magnet in the engine oil tank will get stuck and the cure is to replace the engine oil tank. Just my guess.
Hey Steve the airline pipe from the crank case you refer to on my optimax isn’t connected to anything just a black fitting on the end of it and I can’t see where it’s meant to go. It was tucked up quite high on the port side of the engine I’ve just got this boat and only been out once and when I got in my oil reservoir was lower than half and I’ve never herd any beeps. Nightmare 😂
Hey @huntingorkney, there needs to be a line from the crankcase to the remote oil reservoir. Thats how the system works. Its tucked back behind the oil lines near the oil pump. My buddy has a 2000 Opti and his was a little different. Mine's a 2004.
@@JJ-mz5qw The check valve is a straight brass fitting coming off of the crank case. Air coming from the crank case is what pressurizes the remote oil tank to continuously send oil to the tank on the motor. The check valve fitting has the oil line going to the remote tank connected to it. Really easy to get to and change.
We ended up changing the oil line and the air check valve and it’s been running great for the past 5 months. Just had the low oil alarm go off again and now it’s back in the shop. Very frustrating.
@@SteveSRandomStuff I just went through all of this on my customers 05 Optimax 150. This is only my second Optimax I have worked on. It set a code on the display for low oil level on the secondary tank with the four beeps at the time I didnt know what it was until I did some checking . I took the tank off drained it and looked at the float and it was stuck I even slammed it on the bench and it would not move. It was a 18 Ranger combo fish and ski boat I guess they didnt make very many of them. Anyway it had sat out in the elments the previous owner left the plug in it and just let is sit out in the elements and it fill up with water even with the top of the gunnel it was a mess. He passed away and his son in law brought me the boat. Everything was rancid the fuel tank and the pressure tank for the oil had been submerged in water. I had to pump out the nasty oil pull the tank and clean and flush the tank and lines I also pumped out the old fuel out of the tank and put in fresh. and a tune up and water pump kit. It was a lot of work. Back to the tank I ordered the new tank and it came with the check valve and sensor I also ordered a new inlet filter for it . I took it out of the box and shook it and sure enough the float rattled . I installed the new tank filled it and before I started the engine I hit the cut off for the battery to reset the ECM for good measure . I started it up and the code was clear and no more beeps . I want to add I changed the gear oil and it was nasty I dont think it ever had been changed and it had the factory 18 year old spark plugs complete with the engine paint still on them. There was hardly any electrode on any of them I have no clue why it even ran when he started it . Everything went good no codes and the customer was really happy . These engines are a bitch to work on my supplier in Washington state was back ordered on the fuel filters for over 3 months took me five days to locate a fuel filter I crossed the Merc number over to Wix
Steve, I feel your pain. I’ve got a 2013 Merc 250 Pro XS and have dealing with this very problem for a few weeks now. I replaced the small oil tank on the engine thinking it was the float/magnet on the sensor. A lot of YT videos and forums on line said that was a common problem. I noticed the oil was half full in the small tank so I started going through the system. I changed the inline oil filter ahead of the small tank, cleaned the strainer on the bottom of the pickup tube in the remote reservoir. Pressurized the system with an air compressor and I it filled the small tank. Took the boat out on three different days and on the third day got the low oil alarm again. Went through the system again and replaced the check valve and the o-rings on the remote oil reservoir. Went fishing after that on four different occasions. No problem for three days and thought is was fixed but on the fourth trip out got the low oil alarm again. Went through the oil system again today. I pressurized the system and sprayed a soapy water solution on all the lines and fittings. Had a tiny leak on one of the caps on the remote reservoir, tightened the cap up and stopped that. I replaced the zip ties Mercury uses for hose clamps on either end of the air line from the check valve to the remote reservoir with steel hose clamps. I started up the engine to check for air pressure coming off the engine. That checked out OK. Have to take it to the lake and run it to see if the problem is fixed or not. Very frustrating because it’s such a simple system. Thanks for making the videos. Hopefully your problem is fixed. Keep up the good work.
See the comment I just added below to @Woodys1999 on the recent update.
Great info. JUST bought a Optimax 225 on a project boat.wanted to research how the oil system worked...Thanks for the video
Good stuff... I appreciate the "real world" feedback on your issues and solutions. I have a 1999 225 Opti that's still going strong.
Thanks.
Had the same issue, it turned out that the pick up screen was blocked on the reservoir.
Hope thus helps!
Yep. I ended up replacing the pickup tube and has been fine ever since.
It time for the merc 4 stroke!!!!!!
My screen on the oil pickup was getting slimy and not allowing oil flow. I rinsed it with gas and a toothbrush, changed the oil for fresh and got rid or the low oil alarm. Now I'm having issues with rpm loss at takoff and high speed running. My 2004 200 OPTIMAX is a strong running engine when in shape. It's kind of hard to trust right now in SE Alaska waters.
I had that same issue with the slimy oil and pick up tube. Cleaned it out and used new oil and running great. Sorry to hear about the low rpm issue. Not sure what causes that. Good luck.
Clear lake Tx? I can’t find anyone to work on mine around here. If not a 4 stroke they won’t touch it. I started straining my oil. I’ve found even using the recommended oil it’s clumpy in the bottle. No more issues since. I want to get my poppets replaced also so any direction of where to go will be appreciated.
Clearlake, CA.
That sucks… just found your ch….my 90 opti has run like a Swiss watch for 13 yrs… it’s an 05 … bought used, love it … reliable as can be for myself .. like the vids
I’m dealing with the same thing, I’m about to replace the check valve on mine this weekend.
I’m not getting oil up to the top oil reservoir on the engine on my 1990 200 mercury.
Check the pickup tube in the remote tank. If it has some sludge on the screen, you may have some bad oil that coagulates and plugs the screen. That’s what happened to me. We replaced the tube, cleaned the tank and put in fresh oil. That appeared to solve the issue. Only time will tell.
I ended up taking all the oil and running it through a filter, then replaced all the o rings/pick up and hoses/check valve. One of the rubber grommets for the oil/air manifold was ripped and must have been causing the issue.
I plan on replacing everything else during the winter when the highschool bass season is on break
problem with techs today is that if softweare cant fix it, they are totally lost . diagnostic skills are gone ,most dont know what it takes for an internal combustion engine needs to run correctly.but sounds like you found a tech that may have skills ,keep this persdon on speed dial
For sure. Finally found someone who knows the Mercury motors and can diagnose most problems.
If you pressure tested the tank with the cap on that, should have checked the check valve.
I have heard that the magnet in the engine oil tank will get stuck and the cure is to replace the engine oil tank.
Just my guess.
You know you have a bad magnet with the alarm goes off and the tank is full.
Hey Steve the airline pipe from the crank case you refer to on my optimax isn’t connected to anything just a black fitting on the end of it and I can’t see where it’s meant to go. It was tucked up quite high on the port side of the engine I’ve just got this boat and only been out once and when I got in my oil reservoir was lower than half and I’ve never herd any beeps. Nightmare 😂
Hey @huntingorkney, there needs to be a line from the crankcase to the remote oil reservoir. Thats how the system works. Its tucked back behind the oil lines near the oil pump. My buddy has a 2000 Opti and his was a little different. Mine's a 2004.
I had check valve go bad twice on mine. Same motor.
I had to replace the new air check valve I installed. Had a bad one.
Your talking about the brass fitting by the oil filter? Thanks!
@@JJ-mz5qw the air check valve is on the opposite side on the crankcase. It’s the line from the engine to the oil reservoir.
@@JJ-mz5qw The check valve is a straight brass fitting coming off of the crank case. Air coming from the crank case is what pressurizes the remote oil tank to continuously send oil to the tank on the motor. The check valve fitting has the oil line going to the remote tank connected to it. Really easy to get to and change.
It's the strainer
I replaced the oil pickup tube and flushed out the oil tank and haven't had a problem since. I now use the Quicksilver oil and not the Mercury.
@@SteveSRandomStuff you didn't end up changing the check valve?
I previously changed the check valve on both sides of the engine.
Ok so where is the follow up what happened
We ended up changing the oil line and the air check valve and it’s been running great for the past 5 months. Just had the low oil alarm go off again and now it’s back in the shop. Very frustrating.
@@SteveSRandomStuff I just went through all of this on my customers 05 Optimax 150. This is only my second Optimax I have worked on. It set a code on the display for low oil level on the secondary tank with the four beeps at the time I didnt know what it was until I did some checking . I took the tank off drained it and looked at the float and it was stuck I even slammed it on the bench and it would not move. It was a 18 Ranger combo fish and ski boat I guess they didnt make very many of them. Anyway it had sat out in the elments the previous owner left the plug in it and just let is sit out in the elements and it fill up with water even with the top of the gunnel it was a mess. He passed away and his son in law brought me the boat. Everything was rancid the fuel tank and the pressure tank for the oil had been submerged in water. I had to pump out the nasty oil pull the tank and clean and flush the tank and lines I also pumped out the old fuel out of the tank and put in fresh. and a tune up and water pump kit. It was a lot of work. Back to the tank I ordered the new tank and it came with the check valve and sensor I also ordered a new inlet filter for it . I took it out of the box and shook it and sure enough the float rattled . I installed the new tank filled it and before I started the engine I hit the cut off for the battery to reset the ECM for good measure . I started it up and the code was clear and no more beeps . I want to add I changed the gear oil and it was nasty I dont think it ever had been changed and it had the factory 18 year old spark plugs complete with the engine paint still on them. There was hardly any electrode on any of them I have no clue why it even ran when he started it . Everything went good no codes and the customer was really happy . These engines are a bitch to work on my supplier in Washington state was back ordered on the fuel filters for over 3 months took me five days to locate a fuel filter I crossed the Merc number over to Wix
Mines a 150 opti, about ready to just give up on it. It's starting to nickel and dime me to death!
Thank you for the videos!
I ended up replacing the oil lines because we thought one was pinched and turns out the new air check valve we installed was bad. Now it runs great.