91 Yamaha oil injection problem

[Mikeys250]

I have searched as much as I can and have learned how this system works pretty well. But in kinda stuck on this issue.
The motor is a 90
or 91(model number plate is missing) Yamaha 150 precision blend. First I had no power to the remote pump and checked power all along oil harness with nothing and decided to connected the yellow (key on 12v) that I was told I isn't need to hook to the universal key switch I am using. This got power to the pump but it is constant power, pump runs when hooked up regardless of oil level. I ohm'd the remote float switch and it is good. The main tank float seems to be my problem but I want to be sure its not the control unit.
This is where I get stumped, by ohm'ing the top side float I have infinite resistance for the bottom and middle switches(open circuit) but top switch meaning tank is full and should kill pump gives me resistance of about 20 when it should, then infinite when the float moves down.
By following a trouble shooting article I found it said to ground the white wire from float and if the pump stops then the control unit is ok but float is bad?is this correct? If the float is bad then why did it put motor in limp mode when the main tank was about 1/4 inch below the bottom line?

 

[stylesabu]

Re: 91 Yamaha oil injection problem

so the main tank was close to empty?

 

[Mikeys250]

Re: 91 Yamaha oil injection problem

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so the main tank was close to empty?

Yes I drained almost all of it out to test the oil system

 

[Bamaman1]

Re: 91 Yamaha oil injection problem

Swap the float on the main tank for the float in the small tank. They should be the same float. See what it does.

Or, test each float to see if the ohm's act the same as the float goes up and down.

It's the electronic module that tells the pump to send oil to the little tank, and for the pump to stop when the little tank's full. The module will also throw your engine into a fail safe mode if the main tank level is too low.

The system is actually pretty simple. I had problems with the pump overflowing the little tank, and had to buy a new electronic module.

The oil injection is actually separate from the pump system, and it's completely mechanical. The oil injection seldom causes a problem on these engines if the oil is kept clean--very reliable system. Problems are most often in the module and the floats.

 

[99yam40]

Re: 91 Yamaha oil injection problem

could be the wiring also.
The float switches are different , you cannot swap them

 

[Mikeys250]

Re: 91 Yamaha oil injection problem

We'll folks I appreciate the help but the day after I posted this I went out to retest everything and dang if the system isn't working as it should. I don't know if I had a loose connection or what but I ran it or about 2 hours yesterday without a problem. This is why I hate electrical components, they have a mind of their own