Please help! I’ve got a z7 sport 150HP 2 stroke. Was doing the Intermittent 4 beeps with loss of power. Local mechanic saw that the engine oil tank was less than half and swapped the whole tank out.


Took it out yesterday and it ran for a while, but then the alarm/power loss returned. Checked the engine oil tank and it’s about 1inch low.

I’m just not sure if only being 1 inch low would be enough to trip the alarm
Again? Any ideas!

I've seen this happen when the motor was needing a true tune up, impeller, plugs, etc. Have you tried any of these things?

So far, I’ve swapped: all the old gas out, changed the in line oil filter, swapped the fuel/water separator as well. Spark plugs were changed 9 months ago too.

I'd start with a fresh pair of plugs...they could be damaged or corroded. I used to change mine yearly on my 2 stroke. So 9 months is just 3 months earlier.

I have been told that intermittent beeps were caused by the float in the remote oil tank sticking which is probably why the mechanic replaced the tank. I am having a similar problem in that I have random beeps but I have no loss of power. I have replaced most easy things but will be looking at the impeller, thermostat, pop-it etc.
do you have a way to get codes checked?

Thermostats. Just happened to my buddies 150 Pro xs Opti.

One would assume he purged all the air out, you might try it, won’t cost you anything to do. Just find a YouTube video and do NOT over tighten the cap! If you break the cap, you are replacing the entire tank.

Could be crud in the thermostats, YouTube that one as well. Don’t tear the gasket, or you’ll be buying new ones.

If you fish in a grass/scummy area, the water strainer could be clogged. Doesn’t hurt to clean it, all stuff that you can learn how to do from google or YouTube.

engine oil tank should not get low, check for air leak in hoses to remote tank or bad cap/seal

It's a bad Sencer most likely.

Agree. Would be the 1st thing I'd check. Found a crack in my oil tank cap that caused same problem.

If the tank was less than half full, that would cause the sensor to alarm which is what it's supposed to do. First thing to check is the level in the engine mounted tank. If it's low, once again the sensor is doing its job and you have other problems. If the engine mounted tank is full, remove the connector from the tank and jumper the wires in the harness. If the alarm stops you have a bad sensor in the tank, if it doesn't stop, you have another problem.

How's the battery voltage? My mercury 150 4 stroke is sensitive to a low battery. I had to buy it some chocolate and roses along with the new interstate.

The optimax oil system is relatively simple. Crankcase pressure pressurizes the in boat tank from a line off the starboard front half of the block, which in turn pushes oil up to the tank on the motor. While there are some great maintenance suggestions above, nothing about the engine running quality will cause the oil tank to be low. As long as the engine is running, even if it is poorly, the crankcase will make pressure and keep the oil tank full. Your problem will be somewhere along that short path:
Reeds broken can cause crankcase pressure to drop, only seen that a few times.
Check valve on the block can be stopped up or broken, causing crankcase pressure not to get to the oil tank in the boat.
There is a filter on the bottom of the pickup in the onboard boat oil tank, check it for sludge. They're dirty often.
Check with soapy water for leaks around caps in tank in boat. Loss of pressure there will cause motor tank not to fill up.
You've already replaced your oil filter in line at the motor, that was a good idea though, they clog often.

Your problem is somewhere along that path. Replacing the whole tank on the engine is typically done when the sensor quits reading properly, ie the tank is full, but the oil alarm is going off anyways, and that's not what you were experiencing. You're experiencing a mechanical issue, either loss of crankcase pressure, or a blockage somewhere preventing that pressure from reaching where it needs to go and in turn, oil flowing up to the tank.
Hope that helps.

Have you clean the draw screen on the hose.? Crud build up. Bump start in drive engine down. Cap off on engine and see if it fills up.

This is my issue, but the part is on a national backorder. My mechanic bypassed the alarm and told me to make sure I do not get low on oil.