Oil Level Alarm

[ranger180vs]

My 2003 V150TLRB has a constant alarm with the key ON. Unplugged the oil level sensor on the main tank and the alarm goes off. Bought a new sensor and the alarm did not go away. Looking at it closer, it appears the level sensor operation is inverted - float down = alarm off, float up = alarm on. It's the same for both old and new sensor. Any ideas why this would change and how to fix it?

[boats.net]

Oil level sensor in engine oil tank is one thats activates alarm, the bottom switch activates alarm if float is all the way down and all models work same way. Use an ohm meter and test all three switches.

[ranger180vs]

Thanks for the info. I'm definitely a novice at this. The oil level sensors in both the main tank and the engine tank are new and ohm out the same as the old units. The float on the main tank oil sensor turns the alarm on and off immediately with no delay but it's operation is inverted. The float on the engine tank seems to be working properly. Where do I find the third switch that you mentioned?

[boats.net]

There are three switches in engine oil tank sensor, bootom controls alarm, middle one turns transfer pump on and top turns transfer pump off.

[ranger180vs]

I confirmed the three positions on the oil level sensor in engine oil tank are working using my ohmmeter. When connected and powered the middle position does not turn on the pump. Could CDI be the problem?

[rodbolt17]

its confusing enough.
lets refer to the engine tank as the engine tank and the hull mounted tank as the remote tank.
1995 and up V6 models the engine must be running for normal transfer.
could it be a CDI?
I have actually replaced two CDI units on the 95 and up V6 in the past 15 years.this includes ALL v6 2 stroke models.

what visual indicates lead you to belive its an oil alarm?
what control box do you have?

[ranger180vs]

The inverted operation of the oil level sensor in the remote tank is what's confusing. I put a cable tie above the float to force it in the down position and reassembled. The alarm goes off when the float is down. I put the motor in a tank and ran it for 5-10 min to heat it up. There were no alarms. When I pulled the oil level sensor, removed the cable tie and moved the float up, alarm goes on.

The markings on the CDI unit are: KOKUSANDENKI CU7684 64D-10 3128

[muskrat1]

I just went through a similar issue with a motor I purchased.

My remote tank sensor also functioned 180 out of phase, just as you described. Triggered the key alarm when float was at 'full' and no alarm when float was 'empty'. However, it is not supposed to effect the alarm.

Anytime I heard of this issue - replacing the remote tank wire harness fixed the problem. But not in my case. New harness made no difference.

Not saying my issue is the same as yours. But you never know.

Also, I zip tied the remote float to 'empty' position, trying to fool the system. However, I learned mine would not fill the engine tank rigged this way. Very easy to check.

Empty engine tank pulling water trap tube. Reconnect tube. With full remote tank, and sensor float not jury rigged, turn on key not starting engine. Engine tank should begin filling after 4-5 seconds and stop when gets full.

When I locked float to empty position on remote tank. The remote oil pump would not turn on. But with alarm blarring, and remote float at full level - tank would fill.

FWIW - while trouble shooting, I replaced the following for naught:
Remote tank sensor
Remote tank pump
Remote tank itself, plus sensor & pump
Remote tank wiring harness
On board tank sensor
Cdi box
Key Switch

None of these swaps fixed my problem. Rodbolt pointed me to wiring, and that is where I found my issue.

[ranger180vs]

Thanks for sharing your similar situation. I'll double check all the wiring. If all looks good, I'll replace the harness.

[99yam40]

Testing things is a lot better than just throwing parts at it and hoping.

Do you have a Yamaha service manual for your motor?
If not pick one up , it will help

Here is something that might help, notice that all that needs to happen is grounding of the different wires to cause things to happen. either through the switches or the wiring itself. But need to find out where all the wire go to so you can test for grounds. So wiring diagram for your motor would help
http://www.yamahaoutboardparts.com/a...sortest_91.jpg

[ranger180vs]

Yes - Good advice. Thanks for sharing.

[muskrat1]

I have the service manuals and also tested each component, before and after replacing them. I also did continuity checks on all harnesses and OHMd switches per the manual.

Never found any issues with the testing, which was my stumper. Rodbolts advice got me looking somewhere I never messed with, and that is when we found two wires were not lined up across a connector.

I am fortunate to own multiple boats with similar Yamaha outboards. So I had all the parts at my disposal to use. Also, the other motors helped be test rigs for parts I needed to check, in addition to OHM-ing them out.

All I purchased was one new remote tank sensor & a used key switch. Which I bought after my original sensor was found to be 'working 180 out', and did not OHM right when I first checked it. When the new one acted up....the fun started. Luckily for me, I found out I had a bad remote tank sensor on my other boat, during the swaps...so the new sensor, found itself a new home already.