Starboard Low Oil Alarm - Where to Start

[Pfu]

Last week had the starboard alarm go off related to low oil in the reserve. Poured a gallon of yamalube in the reservoir and alarms went off and displayed ok on the gauge. Today went out fishing and six miles into trip gauge went from full to half to alarm in short period. Bad news was backup gallon was in my car. Shutdown the engine and nursed home with second engine with full oil reservoir.

Boat new to me three weeks ago. Where do I start looking? Engines not smoking so not burning excess oil. Nothing in Bilge. Never notice anything around external to engine displaying leak. Heading back out to boat tomorrow as raining this morning until tomorrow. Bugs me as engines had full maintenance performed in NY before bringing home to VT.

Any and all help is greatly appreciated. May pull boat tomorrow as want to replace the trim tabs as well.

 

[seasick]

It would help to know the engine model but I will assume its a 2 stroke. In that case, there are two oil tanks, a larger one in a locker that is called the remote tank and a smaller one under the motor cowling called the main.
Basically when the main gets low, it sends a signal to a pump on the remote tank that then pumps oil into the main tank (on the motor)
There are different oil alarms that tell you when the remote tank is low on oil and when the main tank is low. The low main tank is more serious since the gas will not get mixed with oil If you get that alarm, the motor will switch to safe mode and the revs will be lowered.
There are cases where the remote tank can not pump oil fast enough to replace the oil the motor is using. When that happens, the oil in the main tank gets lower and lower until it reaches the alarm level. If the flow i slow, it can mean that the remote tank filter is clogged or the tank itself is gunked up.

I can go into more detail about trouble diagnosing but first let us know if the motors are 2 strokes.

 

[Pfu]

It would help to know the engine model but I will assume its a 2 stroke. In that case, there are two oil tanks, a larger one in a locker that is called the remote tank and a smaller one under the motor cowling called the main.
Basically when the main gets low, it sends a signal to a pump on the remote tank that then pumps oil into the main tank (on the motor)
There are different oil alarms that tell you when the remote tank is low on oil and when the main tank is low. The low main tank is more serious since the gas will not get mixed with oil If you get that alarm, the motor will switch to safe mode and the revs will be lowered.
There are cases where the remote tank can not pump oil fast enough to replace the oil the motor is using. When that happens, the oil in the main tank gets lower and lower until it reaches the alarm level. If the flow i slow, it can mean that the remote tank filter is clogged or the tank itself is gunked up.

I can go into more detail about trouble diagnosing but first let us know if the motors are 2 strokes.

Sorry the engines are two stroke Yamaha 150’s. The reservoir is two tanks - one for each engine - under the rear seat of the 232. I was unable to remove the engine cover today as it was pouring out when back to the marina but will check in the morning.

 

[SkunkBoat]

first step...look at the big tank under the seat and the "main" tank inside the motor
is either LOW?
If main tank is low then its not being filled from big tank.

There is a tiny inline filter hidden near the bottom back side in the worst possible place. You have to remove tanks and/or have empty tanks to replace the filters.
(if boat is new to you, replace them both now....don't think just do...)
Pump motors mounted on big tanks can get rusted.
Connections to pump and to float switch for alarm can get corroded

I had all three of those problems at some point on one motor or the other.

 

[seasick]

OK. 2 strokes as I suspected.
There is a tank on each motor, so in total you have 4 oil tanks. Depending on your gauge type, the alarm will tell you what the alarm condition is. Basically there are two separate alarms and you can get one or both depending on the oil levels in the tanks.
In general, the smaller tank on the motor should always be at least half full and at lower speeds full. It has a sensor that signals 3 different states; full, halfish full and low. The remote bigger tank also has a sensor but it has only one signal;low oil.

When you turn on the ignition and any time the motor is running, if the main tank half full sensor is triggered, the computer will send a signal to turn on the pump in the remote tank. That will fill up the main tank on the motor until the full sensor in that tank get triggered. When that happens, the pump in the remote tank is shut off. So during normal operation, the tank on the motor is always somewhere between full and half full. Of course the amount of oil used depends on engine throttle position so at higher throttle settings, the tank empties and refills more frequently. If the oil usage is greater than the main tank gets refilled, eventually the low oil sensor is triggered and a critical alarm is generated. At that point if you were to shut off the ignition and remove the motor cowling, you should be able to tell that the main tank is empty. If you then turn on the ignition but don't start the motor, the tank may refill but somewhat slowly. If it doesn't refill, there is a manual toggle switch on the motor (mine is on the aft end in the middle of the heads on top of the computer module (ECU). Try holding that switch to see if the main tank fills.

Based on those observations, we can narrow down the causes of the alarms.
If during the testing you discover that at lower speeds you don't get the alarm but do at higher speeds, it can mean that the remote tank oil filter/screen is clogged, the remote oil pump is shot or the tank has gunk in the bottom clogging the flow of oil to the pump.
Depending on what you find out, there are additional steps to identify your problem.
So, pull the cowling and find the oil tank. It is a bluish color plastic tank with a black cap with wires on it's top. Then do the tests I suggested. Good luck, hopefully it is something simple. My advice is to find out what id wrong before blindly replacing parts. Some parts are pretty expensive. Parts like filter is cheap but you need to remove the remote tank in most cases to get to it.

 

[glacierbaze]

Not sure which tank your gauge reads, but if you went from full to half to alarm in six miles, you have a major leak, not a filter issue. That should be easy to find, from the mess in your bilge. If you end up pulling the remote tank to fix the leak, or to clean up the mess, by all means, replace the filter.
I think the main tank on the engine is the only one that is alarmed, and as said, you go into limp mode. If it goes off again, shut everything off, if it is safe to do so. Tilt the motor halfway, and pull the cowling. Put the engine back down, and check the level in the main tank, it should be below the bottom line. Open the access to the remote tank, so that you can hear the oil pump, and turn the key on. If the pump is running, but not filling the main tank, you probably have a clogged filter. If the pump is not running, try the toggle switch next to the main tank, and see if it runs and fills. If not, you may have a bad motor.
BUT, you don't have to limp home on one motor. The main tank holds most of a quart, and at 50:1, that's good for 50 quarts of fuel burn, before the alarm comes on again, and hopefully, you are back at the dock before then. You carefully pull the float switch assembly out of the top of the main tank, and pour in the oil to a little over the top line. You won't get 50 quarts out of one shot, but that's the theory.
This is much easier to do from a quart than a gallon, so for that reason, I now keep 2 quarts of oil on board, as well as a gallon in case I forgot to check the remote tank. When it happened to me, I had a full remote tank, but no oil on board, and no way to get any out of the remote, so I had to sit for an hour, until Towboat brought me some oil for the main. If you have a leak draining the main that fast, you may have to crimp the tubing to stop the leak, and fill the main.
As someone said, the filter is in the worst possible place, and you have to pull the remote tank, and probably a battery on that side. Once you pull it, go ahead and drain, clean with something like gasoline, and blow out all the passageways with compressed air, and replace the filter. They're about $20 at a dealer, I bought a bag of 10 for half that on ebay, Chinese for sure, but so may the originals be.
Some will disagree with this approach, but after the second filter, before I cleaned the sludge out of the remote tank, I moved the filter from below the remote to the oil line in the transom well, where I could change it in a couple minutes. The pathway is: Remote Tank--Short Tube--Filter--Short Tube--Pump--Long tube to main on engine. So, by moving the filter to the long tube, the oil going to the pump is not filtered, but it is a diaphragm pump, so I see no harm.

 

[seasick]

The gauge shows both alarms in different ways but it will be obvious if the alarm is for low oil in main tank; In that case the revs will go down as the motors switches to limp mode. There is a separate alarm for low oil in remote tank. That alarm does not put the motor in limp mode.
The comment about consumption and an alarm in a short period of running is not exactly accurate. If the oil level in the main tank is close to empty, and not refilling at the correct rate, the level may very well cross the empty detection level quickly. In that case, shutting the motor off and then turning on the ignition for a minute or so may enable the remote oil pump to pump enough oil to raise the main level above the alarm limit, Depending on the refill rate the motor may be able to run at low revs for a long time.
Also note that if adjusted correctly, the oil gas ratio at low speeds will be more like 100 to 1. The max ratio on a SX motor is about 40 to 1 at WOT.

 

[SeaVee]

Lots of info on this topic over on THT. I am with Skunkboat, go ahead and replace the oil filter and inspect pump on tank, if it looks bad they aren’t too expensive to replace. I had a devil of a time getting this issue sorted out on my 01 HPDI’s. Went ahead and replaced remote tank pumps, those pesky filters under the remote tanks, and the sensors in the remote tanks. Got all the parts from SIM Yamaha. Problem solved and they are purring now.

 

[SeaVee]

Also- ditch the Yamalube and switch to Penzoil XLF. Burns much cleaner and is cheaper. I get mine at WalMart. Making this switch and using Yamaha Ring free will make a big difference

 

[Pfu]

OK. 2 strokes as I suspected.
There is a tank on each motor, so in total you have 4 oil tanks. Depending on your gauge type, the alarm will tell you what the alarm condition is. Basically there are two separate alarms and you can get one or both depending on the oil levels in the tanks.
In general, the smaller tank on the motor should always be at least half full and at lower speeds full. It has a sensor that signals 3 different states; full, halfish full and low. The remote bigger tank also has a sensor but it has only one signal;low oil.

When you turn on the ignition and any time the motor is running, if the main tank half full sensor is triggered, the computer will send a signal to turn on the pump in the remote tank. That will fill up the main tank on the motor until the full sensor in that tank get triggered. When that happens, the pump in the remote tank is shut off. So during normal operation, the tank on the motor is always somewhere between full and half full. Of course the amount of oil used depends on engine throttle position so at higher throttle settings, the tank empties and refills more frequently. If the oil usage is greater than the main tank gets refilled, eventually the low oil sensor is triggered and a critical alarm is generated. At that point if you were to shut off the ignition and remove the motor cowling, you should be able to tell that the main tank is empty. If you then turn on the ignition but don't start the motor, the tank may refill but somewhat slowly. If it doesn't refill, there is a manual toggle switch on the motor (mine is on the aft end in the middle of the heads on top of the computer module (ECU). Try holding that switch to see if the main tank fills.

Based on those observations, we can narrow down the causes of the alarms.
If during the testing you discover that at lower speeds you don't get the alarm but do at higher speeds, it can mean that the remote tank oil filter/screen is clogged, the remote oil pump is shot or the tank has gunk in the bottom clogging the flow of oil to the pump.
Depending on what you find out, there are additional steps to identify your problem.
So, pull the cowling and find the oil tank. It is a bluish color plastic tank with a black cap with wires on it's top. Then do the tests I suggested. Good luck, hopefully it is something simple. My advice is to find out what id wrong before blindly replacing parts. Some parts are pretty expensive. Parts like filter is cheap but you need to remove the remote tank in most cases to get to it.

I should have read the whole string before doing anything.

I first checked the tank under the rear seat. Not empty but low (filled a week ago with one full gallon thinking alarm was from secondary tank). Added a half gallon. No signs of leaking in the bilge (spotless as if new) nor anywhere I could inspect by eye and using mirrors.

Next took off the cowl. Small tank was at the lower line on the tank. Started motor and the tank started to fill when applying throttle. Stopped half way and shut down motor. Turned on ignition and used the switch next to main engine tank and filled to line. I stopped when got to second line not knowing if it would auto stop.

if I guessed the fuel used since last time filling secondary tank I would guess tops of 55 gallons from main tank.

Second engine main tank was at top line and reserve tank under seat is at half. Not had any alarms on this engine. Wouldn’t both engines use same amount of oil in principle? As stated above no signs of leaking at reserve tank nor in the engine area.

Next few days are nothing but rain but will run engines and monitor all oil tanks when possible. I am baffled but appreciate everyone’s insights. Being an IT guy I typically am very methodical and need to know to solve.

 

[enfish]

I should have read the whole string before doing anything.

I first checked the tank under the rear seat. Not empty but low (filled a week ago with one full gallon thinking alarm was from secondary tank). Added a half gallon. No signs of leaking in the bilge (spotless as if new) nor anywhere I could inspect by eye and using mirrors.

Next took off the cowl. Small tank was at the lower line on the tank. Started motor and the tank started to fill when applying throttle. Stopped half way and shut down motor. Turned on ignition and used the switch next to main engine tank and filled to line. I stopped when got to second line not knowing if it would auto stop.

if I guessed the fuel used since last time filling secondary tank I would guess tops of 55 gallons from main tank.

Second engine main tank was at top line and reserve tank under seat is at half. Not had any alarms on this engine. Wouldn’t both engines use same amount of oil in principle? As stated above no signs of leaking at reserve tank nor in the engine area.

Next few days are nothing but rain but will run engines and monitor all oil tanks when possible. I am baffled but appreciate everyone’s insights. Being an IT guy I typically am very methodical and need to know to solve.

From what you state, I'm leaning towards what the others have said... the inline filter in the remote tank is partially clogged, so that the main tank will fill, but not fast enough to keep up at high RPM's when the motor is consuming more oil.

You shouldn't need to start the engine and apply throttle. That won't change the oil pumping rate from the remote tank to the main tank. That oil gets transferred based on a sensor in the main tank that turns the pump on when it gets to about the half way point when the ignition is on.

But I'd start with changing out the filter before spending too much time trying to figure this out. The filter is about $15 and shouldn't take more than about 15-20 minutes to swap out, so it's the cheap and easy place to start... and it's never a bad idea to change out filters.

 

[Pfu]

I should have read the whole string before doing anything.

I first checked the tank under the rear seat. Not empty but low (filled a week ago with one full gallon thinking alarm was from secondary tank). Added a half gallon. No signs of leaking in the bilge (spotless as if new) nor anywhere I could inspect by eye and using mirrors.

Next took off the cowl. Small tank was at the lower line on the tank. Started motor and the tank started to fill when applying throttle. Stopped half way and shut down motor. Turned on ignition and used the switch next to main engine tank and filled to line. I stopped when got to second line not knowing if it would auto stop.

if I guessed the fuel used since last time filling secondary tank I would guess tops of 55 gallons from main tank.

Second engine main tank was at top line and reserve tank under seat is at half. Not had any alarms on this engine. Wouldn’t both engines use same amount of oil in principle? As stated above no signs of leaking at reserve tank nor in the engine area.

Next few days are nothing but rain but will run engines and monitor all oil tanks when possible. I am baffled but appreciate everyone’s insights. Being an IT guy I typically am very methodical and need to know to solve.

Decided to go for a quick ride before rain. Engine oil tank full going out. Five miles in the bay the dash oil light goes from full to half to blinking. Back to the dock and remove engine cover. The main tank is full. Turn on ignition and dash oil gauge blinking.

 

[enfish]

Decided to go for a quick ride before rain. Engine oil tank full going out. Five miles in the bay the dash oil light goes from full to half to blinking. Back to the dock and remove engine cover. The main tank is full. Turn on ignition and dash oil gauge blinking.

That's good info... now it sounds like a stuck or flaky oil level sensor. I don't remember the details on how it works, but it's connected to the cap on the main tank with the wires.

 

[seasick]

So far, good diagnostic approach. here are a few additional things to check. Normally the tank on the motor should be almost full. It should never be lower than the halfish level.Depending on where it was when you turned off the motor it may not be full but in that case, if you turn on the ignition and don't start the motor, the remote oil pump should run and the engine tank should fill if not already full. If that happens and it can take minutes, it means that the remote pump is working and the main tank sensor is also working ( as long as the pump stops when the tank is full.
Now the question is if the tank is getting refilled at a rate faster than the motor is using oil. There is a somewhat complicated test procedure to measure pump rate but I don't do it. It is a pain. If you suspect a slow fill rate, 9 out of 10 times the filter or tank is clogged. Yes, the filter is inexpensive but the pump isn't .

Remember, the remote tank under the seat only signals when it is empty and although that is an alarm. it is not critical as long as the main tank on the motor is very low.
Your Yami gauges will tell you what your alarm condition is but the info displayed may not be intuitive. The yamaha engine user manual has a section on the displays .

Regarding oil usage: In theory both motors should use about the same amount of oil assuming they are run at similar revs and durations. As I mentioned, the oil rate is a function of the throttle position ONLY, not speed, load or any other factor. There is a linkage between the throttle assembly and the engine oil pump (not the same as the pump in the remote tank). That linkage has to be checked as part of routine maintenance and adjusted if needed. Sometimes, the linkage breaks or comes loose. In that case the oil rate will be high at lower revs and will result in higher oil consumption and possible fouling of the plugs. Extra smoke is also likely.

Just to keep honest, there are some more serious and harder to identify oil pump problems that can cause alarms but the frequency of those is very low compared to things like clogged tanks or filter.

 

[Pfu]

So far, good diagnostic approach. here are a few additional things to check. Normally the tank on the motor should be almost full. It should never be lower than the halfish level.Depending on where it was when you turned off the motor it may not be full but in that case, if you turn on the ignition and don't start the motor, the remote oil pump should run and the engine tank should fill if not already full. If that happens and it can take minutes, it means that the remote pump is working and the main tank sensor is also working ( as long as the pump stops when the tank is full.
Now the question is if the tank is getting refilled at a rate faster than the motor is using oil. There is a somewhat complicated test procedure to measure pump rate but I don't do it. It is a pain. If you suspect a slow fill rate, 9 out of 10 times the filter or tank is clogged. Yes, the filter is inexpensive but the pump isn't .

Remember, the remote tank under the seat only signals when it is empty and although that is an alarm. it is not critical as long as the main tank on the motor is very low.
Your Yami gauges will tell you what your alarm condition is but the info displayed may not be intuitive. The yamaha engine user manual has a section on the displays .

Regarding oil usage: In theory both motors should use about the same amount of oil assuming they are run at similar revs and durations. As I mentioned, the oil rate is a function of the throttle position ONLY, not speed, load or any other factor. There is a linkage between the throttle assembly and the engine oil pump (not the same as the pump in the remote tank). That linkage has to be checked as part of routine maintenance and adjusted if needed. Sometimes, the linkage breaks or comes loose. In that case the oil rate will be high at lower revs and will result in higher oil consumption and possible fouling of the plugs. Extra smoke is also likely.

Just to keep honest, there are some more serious and harder to identify oil pump problems that can cause alarms but the frequency of those is very low compared to things like clogged tanks or filter.

You guys are amazing. When I purchased the boat I was told the starboard throttle cable was replaced by dealer. Not sure why both were not done in pairs. Based on the above comments this sounds like maybe we are onto something. Note in the picture of the main oil tank the oil was above the line. I was thinking it wanted to be in between like on a car where cold/hot come into play.

The previous owner put nearly $8K into the engines not because it needed it but because he wanted to feel safe. Oil pumps were both replaced. A Grady shop did all the work and the survey did not show anything on engines of concern.

Rain next two days but will call the Grady shop to see if they didn’t do something that was recommended. Will also order filters.

 

[Pfu]

That's good info... now it sounds like a stuck or flaky oil level sensor. I don't remember the details on how it works, but it's connected to the cap on the main tank with the wires.

Is it normal the cap is zip tied? Both are on my engines. Wasn’t sure if possible pinching could come into play.

 

[SkunkBoat]

zip ties normal. Loose cap causes dripping oil in motor up position

You say Oil Pumps (in the big tanks)were replaced? I would hope that they drained and cleaned tanks and changed the little filters and any tubing that looked sketchy.
Because nobody in their right mind would just change the pump motors.

That would make us assume that all of that is working. I'm skeptical.

So, based on your photos, you could have a float sensor problem in the main (small) tank. You can remove the cap and test the float to make the alarm go on & off.
Make sure it does not get stuck in a low position. Check plug/wire connections. You could even swap the cap/sensor between motors and if the problem moves then get a new one.

 

[seasick]

You guys are amazing. When I purchased the boat I was told the starboard throttle cable was replaced by dealer. Not sure why both were not done in pairs. Based on the above comments this sounds like maybe we are onto something. Note in the picture of the main oil tank the oil was above the line. I was thinking it wanted to be in between like on a car where cold/hot come into play.

The previous owner put nearly $8K into the engines not because it needed it but because he wanted to feel safe. Oil pumps were both replaced. A Grady shop did all the work and the survey did not show anything on engines of concern.

Rain next two days but will call the Grady shop to see if they didn’t do something that was recommended. Will also order filters.

Normally I would expect the oil to be at the top of the tank

Nobody I know would spend $8,000 on motor work just to feel safe unless something was seriously wrong.
There are two different oil pumps, one electric on the back of the remote tank and one 'mechanical' on the side of the motor bolted to the crankcase. I would not expect those to be replaced if working. They rarely fail ( the mechanical ones)
In general a survey of a boat would not include testing of the motor. That is separate task dome by a mechanic. The surveyor may do a visual inspection of the outside and perhaps under the cowling but that is not the same thing as a mechanic's testing.

One more fact and please make sure you understand this one. The oil pump on the engine, the mechanical one, has absolutely NOTHING to do with a low oil alarm, NOTHING. If that pump fails, you will not get an alarm but may blow up the motor due to no oil. That is one of the shortcomings of the Yamaha Precision Oil system. The good news is that those pumps rarely fail.
Focus on the initial steps that have been presented to narrow down the most common possibilities, at this point you have no reason to look at other parts.

 

[Pfu]

zip ties normal. Loose cap causes dripping oil in motor up position

You say Oil Pumps (in the big tanks)were replaced? I would hope that they drained and cleaned tanks and changed the little filters and any tubing that looked sketchy.
Because nobody in their right mind would just change the pump motors.

That would make us assume that all of that is working. I'm skeptical.

So, based on your photos, you could have a float sensor problem in the main (small) tank. You can remove the cap and test the float to make the alarm go on & off.
Make sure it does not get stuck in a low position. Check plug/wire connections. You could even swap the cap/sensor between motors and if the problem moves then get a new one.

New oil filters should be delivered today. Is there any concern of air getting in the line from the secondary tank going to the main on the engine? Plan on draining both tanks and cleaning per everyone's recommendations. Second process will be checking out float alarm on main tank. Fingers crossed.

I got to thinking (I am an IT guy) I should purchase a service manual for the engine but there appears to be several types of manuals. Any recommendations for my 2000 Z150TXRY?

 

[seasick]

New oil filters should be delivered today. Is there any concern of air getting in the line from the secondary tank going to the main on the engine? Plan on draining both tanks and cleaning per everyone's recommendations. Second process will be checking out float alarm on main tank. Fingers crossed.

I got to thinking (I am an IT guy) I should purchase a service manual for the engine but there appears to be several types of manuals. Any recommendations for my 2000 Z150TXRY?

Private Message (PM) me on this forum with your email address and I will try to send you an electronic copy of the service manual.