How to replace/fix sticking oil tank float sensor?

kriphead

Cadet
Joined
Jun 9, 2009
Messages
29
I have a 1989 90Hp 3 cyl 2 stroke Mariner Outboard - Serial Number of Motor is: OC206555

My oil float sensor in the bottom of my oil tank will not float, which is causing the oil pressure alarm to go off. The engine IS getting oil, and the sensor is working fine.

I have used a small stick to manually raise the float (I do not feel any resistance when raising it), and the alarm stops, but the oil does not seem to keep the float "floating". I can't seem to figure out how to get the float out to see what is wrong with it, or is it built in the tank itself?

Any ideas how to fix this issue?

Again, the engine is getting oil, and the I have diagnosed the problem to be the float inside the oil tank, how to fix this.

Thanks again

K
 

CharlieB

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Apr 10, 2007
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5,617
Re: How to replace/fix sticking oil tank float sensor?

It is next to impossible to repair, not impossible, but almost.

Most all us give up and order a new tank assy.
 

kriphead

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Joined
Jun 9, 2009
Messages
29
Re: How to replace/fix sticking oil tank float sensor?

Thanks for the fast reply.

Just out of curiosity, why does it not float? I really don't understand it. Especially since I can manually manipulate it without it feels like it is sticking???

THX

K
 

flymhi

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Sep 17, 2011
Messages
3
Re: How to replace/fix sticking oil tank float sensor?

The yellow float that you see has a magnetic ring that adheres to the bottom of the float. These two will separate over time and the magnetic ring falls to the bottom of the plastic shaft regardless of the position of the yellow float. I'm sure a petroleum based adhesive sitting in a petroleum product was not meant to last a lifetime.


Thanks for the fast reply.

Just out of curiosity, why does it not float? I really don't understand it. Especially since I can manually manipulate it without it feels like it is sticking???

THX

K
 

kriphead

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Jun 9, 2009
Messages
29
Re: How to replace/fix sticking oil tank float sensor?

Well, if this was the case, wouldn't the yellow float then float more easily? Perhaps it's the magnet from the tank that has come off and sticks to the float then? Although how was that then connected in the first place? I still don't get it.
 

CharlieB

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Apr 10, 2007
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5,617
Re: How to replace/fix sticking oil tank float sensor?

Think of the float as a donut that is limited in its travel up and down a stick.

When the adhesive fails to hold the magnet to the bottom of the float ;

1 it is extremely difficult to get the float out of the tank, and just as tough to get it back in without breaking something

2 it is extremely difficult to clean oil-soaked materials well enough for any adhesive to successfully re-bond them together.

A new tank assy is roughly $100, you will spend far more effort in attempting to fix the old one before you finally break it and have to buy the new tank assy.
 

bogieman

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Apr 2, 2007
Messages
1
Re: How to replace/fix sticking oil tank float sensor?

It is next to impossible to repair, not impossible, but almost.

Most all us give up and order a new tank assy.

In my case on a 1995 50hp Mariner, you can clearly see the oil level on the front of the engine. I see no reason for the float to start with, and no reason to repair. This motor uses so little oil, there is no reason I can think of to repair/replace. I just bypassed the sensor.
I know there will be those to say one day I'll regret it, but as slow as the level drops and I always keep it topped off, so it will never be a problem for me at least.
 

CharlieB

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Apr 10, 2007
Messages
5,617
Re: How to replace/fix sticking oil tank float sensor?

Fortunate that bogieman's model has a visable sightglass, most motors do not and require the operator to either remove the motor cover to look or pull the dipstick/fill cap.

Even then, say an operator sees a half tank, has a 3 day week-end on the water with family and friends pulling a tube. If not checking the oil daily could still run out and hurt the motor.

Factory alarms are there for a reason, to save motors. Granted SOME individuals may be so anal that they check every little thing before every engine start up, but most do not, thus the reason for mechanics. Lot of damage due to simple operator error.
 
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