Yamaha has a much better system then most, but none the less its what killed my Yamaha!!
I tryed to not use it at one point, but kept fouling the plugs at a 50:1 mix?? So I hooked it back up, thats not saying i did it right?
One thing i nwas told by a yamaha guy was to run mix in the spring with the injection also, you will get double oil, but this is ok as the motor dry after sitting all winter, and you can watch the oil level going down in the tank so you know its working after a long winter nap.
That was the first time i did not do it and blew it
cause they mix any were from 100:1 to 50:1 depending on speed, if you do a lot of trolling nthe 50:1 was to rich. So might have to run a different ratio?
sorry this is not a fix but just letting you know what was told to me and what has happened.
Also found this on a site
The oil tank on the engine supplies oil to a pump on the port side of the block. Remove the hose that exits from the pump and plug it. Plug all nipples on the pump. Drain the oil from the tank on the engine and plug all hoses on the tank. Disconnect all electrical to both tanks, and plug all hoses.
I will look through the manual to see if I have left anything out, and post any further info here.
After looking through some manuals, I see that on your engine, there should be an oil line from the pump on the engine to each cylinder separately. In that case, you should plug each line. You could snip the lines a couple of inches from each end and plug the short remaining pieces on the pump and intake manifold.