2005 Mercury 150hp XR6 Oil Alarm After High Speed

[McGR]

My son bought a Nitro bass boat with a 150hp XR6 earlier this year. This boat and motor has been a bit of a learning curve for us (getting it started is a real challenge for the uninitiated), but we've got to the point where it starts ok and runs well.

The only remaining issue is (we think) the oil alarm. We fish a lake with early morning wake restrictions. At the beginning of our day the motor barely gets above idle. During this period, we never hear the alarm. Once no wake ends and we run the boat WOT, the intermittent/synchronous beeping alarm sounds. We can't really hear it when running WOT, because the alarm is not too loud. Once we slow down we hear the beeping.

There appeared to be oil in the main reservoir, nonetheless, we added 2 quarts to it yesterday before we went out... didn't change anything.

Any insights and advise regarding this are much appreciated. Thanks.

 

[Dukedog]

there are only two sensors that will trigger an oiler alarm when all is workin' as it should, low oil in motor tank and rotation sensor (this one is kinda iffy sometimes)
does tha motor tank stay full (or close to it) on its own?.. if it does ya may have a faulty contact in tha cap.. when you get an alarm disconnect tha blue wire from it to tha alarm module.. should stop buzzer good or bad contacts in cap...

 

[racerone]

When you buy a used boat / motor the first item to do is a new water pump impeller.

 

[Dukedog]

forgot... you can test tha contacts in tha cap with a continuity test.. connect leads to tha blue and black then move tha float up and down tha shaft... should make and break tha reading.............. make sure tha float moves freely on its own and doesn't stick anywhere....

 

[McGR]

Duke - Thanks for the advise. Regarding the float switch... What are the states of the switch in relation to the oil level? Is it...

A
Oil Full = Switch Closed (0Ω)
Oil Empty = Switch Open (Infinite)

or

B
Oil Full = Switch Open (Infinite)
Oil Empty = Switch Closed (0Ω)

Based on your comment to disconnect the wire, I'm thinking "B" is how the switch operates.

Racer - The impeller was replaced earlier in the year.

 

[Dukedog]

best i remember its B.. continuity will tell ya... no readings involved, jus make or break... if it doesn't do that its bad... sounds like it may have a "sticky" spot in tha travel somewhere...

 

[McGR]

Yeah, I'm sure it's one of those typical reed switch/magnet float deals... I guess the make/break situation will be obvious once we start tinkering with it.

 

[Dukedog]

should be.. are tha "self test" beeps operating as they should?

 

[McGR]

I think we get a single beep upon starting. Is this the self test?

 

[Dukedog]

should be three.. think two quickies and one justa tad longer... erratic test beeps usually indicate a bad module

 

[Dukedog]

guest its oilin' ok though??? evidently it is if you have been runin' it with this problem....

 

[McGR]

I'll have to pay closer attention to the beeps on start up... It makes blue smoke, so I think it's oiling ok. Thanks.

 

[Dukedog]

do you know tha history of tha motor?.. reason i asked is if its ever been over heated either one or two times being major or if its been over heated several times being minor ya might consider an oiler delete....... any type of heat weakens tha ring gear on tha crank...

 

[McGR]

We haven't over heated it. Not sure about it's past... I'm been an OMC guy for many years. I always got rid of the VROs on them. Pre-mix is the best oil injection you can get. But my son probably prefers the convenience of the oil tank. If it was mine I'd get rid of it. But, I'm old school like that....

 

[Dukedog]

you and me both............. it is convenient for most though.. i've never kept it on anything i had but most of my stuff i twisted way up on tha rpm scale... good luck and hope ya solve this little inconvenience..............

 

[McGR]