150 prov overfilling small motor attatched oil tank

checked the float .or could it be the emerg switch.it will over fill soon as you turn power on the switch or key.

you need to check the float in the main tank (it's the one on the engine). It sounds like it's not shutting off the reserve pump (the one in tank in your boat). You can stop the pump by disconnecting the blue wire at the pump (you'll need to do this to test the system anyway). Yamaha uses an active ground system, which is to say that all hot wires are hot and connecting the ground controls the system.

Pull the main tank sensor and check that the screen is not blocking the sensor. To do this make sure the hole in the screen is aligned with the flat spot on the top of the sender and the dent in the screen matches up with the bump at the top of the sender. You'll also find a couple of alignment marks on the tank/sender those must be properly aligned.

If all of those are in place then you’ll need an OHM meter that has a diode test option (most do) to test the sender. That is kind of a long sequence to type out so try the other stuff first and get back to me.

thank you for your time,the float in the main tank is about 4 inches long has a plastic skirt with 2 levels of holes in it in side is a 1 inch plastic slide on a brass shaft. i took this apart by pulling a clip off the bott and making shure it slides good as this boat has been setting 2 years. i slid the float manualy up and did not stop pump action.it has a emerg switch to pump oil back into boat tank but i could not get it to work either.again thank you for your time .mark

150prov overfilling

checked all the floats .the emerg wont backfill big tank could this switch be the problem. thanks mark

Ok the "main" tank is the one on the engine, the "reserve" tank is the in your boat. The manaul switch will not pump oil to the main tank unless both the main and reserve tanks are below 1/4 full. This is so that you are aware that the reserve tank is running low and needs to be filled.

The pump on the reserve tank is con*****ed by the float on the main tank. When the main tank is down to 1/2 full it signals the pump in the reserve to pump oil to the main. The only reason why the pump on the reserve would be pumping oil to the main is because the main float is telling the reserve tank that it needs oil. The float on the main tank holds a small magnet that in turn signals another magnet located in the sensor pipe. If any kind of varnish has built up on the brass sensor it can stop the magnets from seeing eachother. Try cleaning the main sensor with carb cleaner and steel wool.

BTW there is no feed back to the boat tank. Follow the tube on the top right of the main tank and you'll see it exits just under the cowl. In other words your pumping oil on to the ground.

prov 150 over filling

thanks again,ill try cleaner and steel wool i have already tried deisel fuel .how easy do these go bad.and what is the best oil to use as i have read on this site about bad stories about cheap oil. also read your problems your having.mine dosnt seem so bad now.lol .good luck mark .oh ya just to make sure on the float does the metal ring on one side go up or down i have it up now. or does it matter.

150prov overfilling main tank.

i cleaned and steelwooled the shaft still no luck guess needs to test it next.iwould just buy one but hate to be wrong .what is the method for testing this. thanks mark.