yamaha v-max 150 problems

longdude17

Seaman
Joined
Sep 3, 2002
Messages
64
Hello everyone. I got a problem

I got a 2000ish (its got carbs) yamaha v-max 150 outboard that has started acting up bad. Now this boat is not mine but is a loaner from a good friend and i was driving it when it happened.

I launched the boat and had it idleing 10 min or so waiting on my gf to park the truck and come to the landing....we loaded up and headed down river...i jumped up on plane running a little over 3/4 throttle for about 1 or 2 min and the motor started loosing power, and lugging down. I came off the throttle, checked my primer bubble, checked to see it was still peeing good...only thing out of the ordinary was a slight tinking sound.

i turned the boat around and head for the landing...jump back up on plane going half throttle for 1 or 2 min and loose power again...i floor it and it doesnt pick up speed....i set her back down in the water and hear a loud tinking sound and the idle is up and down and finally she dies.

I pull the cover off and pull the plastic cover off the flywheel, and manage to get it running again, but there is a pretty loud metallic TINK TINK TINK sound coming from (i guess) under the flywheel.
I can shake the flywheel back and fourth and somewhat reproduce the sound....is this related to why the boat lost power? Is this something that is easily fixed as im pretty mechanically inclined? Whats under the flywheel that can cause this sound? I know the magneto is under there but ive never heard of these tearing up on these motors.

Now it wont even start up...Whats is yalls guess as to what went wrong?...it was a GREAT running boat until yesterday

Any and ALL opinions welcomed.

DE
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,135
Re: yamaha v-max 150 problems

Like all motor troubleshooting always start with testing compression and spark on all cylinders. If all is good the make sure the timing is doing its thing and then look at the fuel.

You can do a forum search for making a spark tester and a DVA adapter or buy them

The way to test the ignition system is in a good Yamaha service manual and you would need a peak reading voltmeter or a DVA with a regular meter.Manual gives a step by step procedure and the specs. make sure the manual is for the motor you are working on.

There are magnets glued into the flywheel that run past the coils. Something could have come loose and is hitting. I sure hope you are not describing a piston/rod noise
 
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