Thanks in advance for looking at my post and any help is welcome. I have a 2004 Yamaha V-Max V150 TLRC that is 3 months out of warranty. Im an ASE certified master tech and plan on doing the work myself ( factory repair manual on the way) This happened at 1200 rpm cruising in 10 feet of water (the lake I was on had 8 mph speed limit) Im positive I didnt hit anything. The engine made a somewhat loud snap or crack noise and a hard jerk followed then a loud rapid knocking. I shut the engine off and checked the lower unit, when I re started the noise was much quieter. The engine never missed and a couple of stabs of the throttle in gear seemed like the power was ok. I shut the engine off and went in on the troling motor. Out of the water I pulled the plugs, they all looked ok, and looked in on top of the pistons and didnt see anything that looked abnormal. Looking through the carbs the reed blocks, at least the ones I could see, looked ok. The noise is hard to hear at idle now and the best way to hear it is to accelerate in neutral. I listened to it with a mechanics stethescope and the noise seems to be coming from the right lower cylinder when viewed from the back. (sorry I dont know the cylinder configuration) also the knocking gets noticably quieter when that spark plug wire is pulled off. This knocking noise sounds like a rod knock in a car engine. Has anyone seen this before in this engine? Does Yamaha have any service bullitins relating to this? Are there any particular problem areas that I should look out for if I have to pull the crank out of this engine?Thank you for your time and help!
