Sparkplug problem

[DChamp]

I have a 2000 225 V-max EFI on a 2000 Champion 203. I'm running a 27M prop. With 2 people and tournament load boat will run 71.9 mph GPS at 5,800 rpm. The problem is the plugs (BR9HS-10) only last about 4-6 months before I start losing rpms. The motor does seem to smoke quite a bit at start-up. I haven't checked the gap on the oiling lever at the throttle yet. Is there anything else to look for? This is my first Yamaha and it is really strong and reliable.

[looking4five]

I have seen quite a few people on here say they had to clean, or replace the oxygen sensor on the OX66 engines periodically. I know some of them just soak the sensor in sea-foam, and it works fine afterwards. I'm sure someone else will be along that knows more shortly...Good Luck getting it straightened out.

[21XDC]

Adjust your oil pump linkage and run br8hs10"s.

[DChamp]

I checked the linkage gap, it was .015". I allready cleaned the O2 sensor. Is the BR8HS-10 a hotter plug?

[STROKEDYAMAHA]

JMHO use amsoil.....It stopped any and all my o2 woes

[tnmark]

Yes , the BR8HS-10 is hotter. I had the same problem with a 2003 VMAX, put the hotter plugs in it and adjust the oil injection pump linkage, I went from changing plugs once a month to once a year!

[DChamp]

Bought the BR8HS-10 plugs and put them in. Adjusted the oil injection pump linkage as the manual said. Now I just have to find the time to try it out before the next tournament.

[DChamp]

Went ahead and changed out the thermostats, put in BR8HS-10 plugs, and set the oil injection linkage to .001-.003 clearance at zero throttle (as manual said). I thought I read about a larger gap on this linkage in an earlier post, just not sure. Is the Amsoil synthetic oil?

[21XDC]

Amsoil is a synthetic.... But you have fixed 99% of the problem... I also run Amsoil HPInjector oil. Good stuff... Let us know how it runs when you run it next.