I have a 2002 Yamaha 175 Vmax HPDI and I have been unable to determine the proper fill level of the main oil tank on the outboard. I assume that it should be at the upper fill line. Right now my level is about 1-1/2 inches above the upper line.
I have had nothing but problems with the Precision Blend system since I purchased new in 2002. I took it back to the dealer numerous times under warranty to fix plug fouling and excessive smoking. The dealer always said that they adjusted the linkage and I should be good to go. I finally had to yell at Yamaha to get the dealer to look into the problem more thoroughly. The final resolution was they found excessive oil in the air silencer at that they replaced a sensor.
From what I can determine it looks like the main oil tank on the engine is filling too high and either when I tilt the engine or I am in rough water, oil is going out the overflow into the air silencer causing the smoke and plug fouling.
Can anyone out there tell me if I am on the right track and what I can do to resolve this problem once and for all. Any help would be greatly appreciated.
The trim sender tells the pump when to shut off the oil flow to the on-engine tank. I believe this started when people were turning on the ignition when the engine was tilted all the way up, and oil would over-fill the reservoir, much as you're seeing. Then the sender was tied in to the rest of the oiling system and when the engine was tilted beyond full trim, no oil was allowed to be sent to the reservoir. Unfortunately, sometimes the trim lever would break, the system would sense that the engine was at full trim + and wouldn't send oil to the reservoir. Working backwards from this, see if your trim sender is stuck in the DOWN position, allowing oil to run all the time from the on-board tank to the reservoir.