Re: 2004 Yamaha 150 VMAX stalls out at half throttle
My 2004 Yamaha 150 VMAX 2 stroke has been stalling out when it gets to half throttle. The boat cranks fine and idles fine but shuts down if you get to half throttle. Fuel pump has been replaced and that was not the problem. Anyone have any ideas?
I have the same model, but from 2003, and it's doing the exact same thing. My story is a little bit depressing, and somewhat complicated, but I'll try to keep it short. I bought a boat off a guy that had a 1999 Yamaha 150 VMAX OX66 TPR, model number DX150TLRX. It got inspected, had full compression but needed a water pump. Lesson learned: never buy a boat that you're not able to test in the water for whatever reason. I bought the boat anyway at a reduced price and took the responsibility of fixing the water pump at my own expense. OK, so two weeks later, water pump is fixed and I put the boat in the water. As I accelerated, suddenly the throttle would cut. Then, 30 seconds later, the engine stopped firing on all cylinders and crapped out. Turns out there was extensive corrosion inside the motor, crankshaft, pistons, contacts... everything was water damaged and two of the injectors stopped injecting altogether. So, after months of... (insert long story here) ... I bought a 2003 Yamaha VMAX 150 HPDI OX66, model number VX150TLRB. It's basically the exact same motor, 4 years younger, with a regular foot/prop. All I did do it was have the garage swap out the foot for the 1999 dual prop out of simple preference.
So I get out on the water and after 5 minutes of normal operation, you guessed it, the throttle starts cutting out at around 2000 RPM, but runs fine at under 1700. Now what are the chances that I have the same problem with both motors? Water in the gas tank perhaps? I had the tank completely pumped out to empty and then refilled it. The red water indicator in the fuel filter has not moved up. I even tried running the motor on a separate gas tank and it still did the same thing. I changed all the spark plugs, again to no avail. Could it be my dual prop, somehow causing too much resistance and forcing the engine to cut out? Other than the gas tank, it's the only common link between the old 1999 motor and the replacement. But the garage checked out the gearcase and it was turning fine. I'm all out of ideas.
So what was your issue after all? Did it get figured out? Does any part of this story sound familiar to anyone?