I have a 2009 Yamaha v-max 150. I always use Marine Stabill when I fuel up. But I keep fouling plugs. When I first got the boat, I could pump the fuel bulb, hold the key in(choke)and it would crank pretty easy. Now, I hold it in for so long I think I'm gonna run the battery down. Any ideas?

Best motor I ever owned was a 2000 Yam V-Max 150 ox66! Never ever had a problem starting and always ran Ringfree in it. I also used the Marine Stabil and never had a problem either.

Is it over-oiling and fouling the plugs?

-alton

same here stabill and ringfree

Probably wouldn't hurt to try ringfree.

You might need to check the oil link rod adjustment and choke rod adjustment.

THIS is why I dont even attempt to work on marine engines!!! LMAO!!

good luck with it, but I would send it to the doctors and let them fix er up ! Carbed motors are a PIA!!!

Ring Free is great stuff and will probably solve your problem.

I add 1oz. to every 10 gallons of gas and it will keep your engine clean.

Had the same problem with my 2009 VMax 250. Don't believe the ring free and stabil stuff! I can't remember the name of the part that was replaced, but it had something to do with the exhaust backflowing causing the plugs to foul. Take it to a good mechanic and they should be able to fix it. You can call Ken at Boerne Marine who fixed mine and he may be able to tell you the name of the part. His number is 830-816-2130.

I've got the VMAX 150 and haven't had a problem. Next time you're on the water, after warm up, activate your key choke and see if the motor starts to die. That'll at least tell you if your choke is working.

Sounds like it could be a cracked reed. When they crack the motor gets to much fuel and it floods out and fouls the plugs. Happens on all carb motors. The Mercury EFI reeds are to be changed every 100 hrs so I was told by a Mercury Tech a few years back.Hope you catch it before it breaks off, cause it is not good if it sucks it through. One other thing make sure motor is level when cranking it. This should help.

Check your low pressure fuel pumps. Loosen the pump bolts enough to pull it away from motor. Then squeeze the bulb and if fuel comes out the back ,it needs replaced.

i had a guy at a dealership tell me it's because i tilt the motor up and oil runs into the carb causing the bottom two plugs to foul.
once i went to lake holbrook and when i tilted the motor up and pulled up to park,i walked back to put the transom saver under the motor. i noticed oil was running down the motor. i thought i'd blown an oil line. took it to shop and they charged me $100 bucks to tell me a piece of a leaf got into the "oil tray" and clogged something up. now, i'm still trying to figure out out in a system where oil goes from a closed reservoir that goes directly to carburator, how did a leaf get into the carb?