Oil keeps pumping!! bad sensor???

Asainz320

Petty Officer 2nd Class
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Sep 27, 2006
Messages
137
i have a 1989 150hp yamaha. My oil pump keeps pumping oil to the tank on the engine! It gets full and starts spilling it all over the engine. What can be wrong with it?
 

bowhuntrrl

Petty Officer 1st Class
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Mar 26, 2003
Messages
320
Re: Oil keeps pumping!! bad sensor???

I would say that it would be a defective sensor not telling the pump to turn off.
 

drewmitch44

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Jun 26, 2005
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1,749
Re: Oil keeps pumping!! bad sensor???

With the external oil tank disconnected turn the key on and take the cap off of the oil resiviour on the inside of the cowling. There is like a dip stick with 3 sencors. If you take the whole cap off and the dipstick out of the oil it will sound a alarm cause it thinks there is no oil there. If no alarm then your sensors are bad or there is a disconnected wire somewhere. Good luck i hate electrical problems!!
 

drewmitch44

Lieutenant Commander
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Re: Oil keeps pumping!! bad sensor???

Did you just get this motor?? If so maybee the previous owner was premixing and not using the precision blend system.
 

JUSTINTIME

Captain
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Sep 2, 2006
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3,284
Re: Oil keeps pumping!! bad sensor???

i have the dealers training trouble shooting guide
shoot me an e-mail
 

Asainz320

Petty Officer 2nd Class
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Sep 27, 2006
Messages
137
Re: Oil keeps pumping!! bad sensor???

I dont think the previous owner was premixing cus the system is all hooked up and working. I took off the line that goes from the oil tank to the pump that pumps the oil to the carbs and i see it sucking down the oil in the line when i turn the engine on.
Is there any way to check that sensor? I took it off and opened it up. The float thingy goes up and down without a problem, but no alarm and no stoping the oil pump. How can i test the sensor with a meter? Thanks for your help guys.
 

Ray Neudecker

Lieutenant Commander
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May 25, 2004
Messages
1,656
Re: Oil keeps pumping!! bad sensor???

Sounds like the oil control module is bad. Unbolt it and see if it is all bubbled out on the back side. Usually means it is shorted if lighter colored section is bubbled.
 

Asainz320

Petty Officer 2nd Class
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Sep 27, 2006
Messages
137
Re: Oil keeps pumping!! bad sensor???

Sounds like the oil control module is bad. Unbolt it and see if it is all bubbled out on the back side. Usually means it is shorted if lighter colored section is bubbled.

ok I will try this. Can this be checked if i find that it isn't bubbled up?
 

rodbolt

Supreme Mariner
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Sep 1, 2003
Messages
20,066
Re: Oil keeps pumping!! bad sensor???

bad switch or module. easiset way to test is unplug the engine tank. on the engine side of the harness with key on engine off is to jump the white to black or known good ground, if it turns the pump off the switch is bad if not most likly the controller is bad.
if your tank uses the switch with a screen make sure you retieved, and replaced with a new one, The oil seal.
brown to black turns the pump on,white to black turns it off and red to black sets both an audible and visual indicates.
 

Asainz320

Petty Officer 2nd Class
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Sep 27, 2006
Messages
137
Re: Oil keeps pumping!! bad sensor???

Hey thanks a lot RodBolt for those details, that was exactly the kind of tests i was looking for. I will try that tomorrow and will let you guys know. Thanks.
 

Asainz320

Petty Officer 2nd Class
Joined
Sep 27, 2006
Messages
137
Re: Oil keeps pumping!! bad sensor???

I tested the sensors with a continuity meter and they're fine. I then took off the control unit and when i turn it front side down it shuts off the oil pump. What does this mean?
 

Ray Neudecker

Lieutenant Commander
Joined
May 25, 2004
Messages
1,656
Re: Oil keeps pumping!! bad sensor???

This means the mercury switch in the pump is working. It is there to keep the pump from working when the engine is in the tilt position.
 

Asainz320

Petty Officer 2nd Class
Joined
Sep 27, 2006
Messages
137
Re: Oil keeps pumping!! bad sensor???

YESSS!!! Its working now!! Thank you for that link edgutgesell!! A lot of good info in there.

It was actually the battery level!!! I read in the link that when the battery is weak the control unit goes crazy. Here it is:
From Article said:
"Leaving the key on by mistake can also cause overflow problems. As the battery run drops below 9.5 volts, the oil-controller electronics go off line, and a ground path is formed which starts the electric pump turning very slowly. Eventually, the main oil tank overfills and spews excess oil out a vent tube into the air silencer box."

I want to thank evryone for your help i really appreciate it. You guys saved me $187 lol. I was about to go and buy the new control unit only to find out that mine was good :) im really happy. Thank You!

Alain
 
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