I originally posted several months ago in this thread http://216.37.204.5/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=1&t=005711 that I was riding along and all of a sudden the ski just shut off and would not start again. Acted like the starter had died or something. Well, we (the shop and I) had determined that it must have been some kind of mechanical failure because after I put the ski back in the next day it ran great 7270-7290 rpms and approx. 70 mph. Well that was when the temp was aboiut 75 degrees. Lately I have been riding in 85-90 temp and my rpms are only 7110-7130. The ski is also significantly slower, especially from midrange to top end. I pulled the plugs and noticed that the plug closest to the front of the ski was pretty dark and the other two were the perfect color like a penny. I next checked compression earlier to find that the first two cylinders that had good plug color were both right at 145psi and the one that had the dark plug was only registering 110psi. Obviously something with this cyclinder is fouled up. The ski still runs 75% okay in the water and will still hang with a stock XP limited. Do you think that I actually may have a seizure or could it even possibly be a bad powervalve? I am taking it to the shop tomorrow and am going to have them pull the head and look around. Can a bad powervalve cause you to lose 150-160rpms?

[ 05-05-2002: Message edited by: '01gprman ]

Did you check your compression with power valves open and closed? If the valve dropped it's likely your #1 will not register any differently open or shut while 2 and 3 will vary about 10 psi.

quote:

---

Originally posted by gp12trpl:
Did you check your compression with power valves open and closed? If the valve dropped it's likely your #1 will not register any differently open or shut while 2 and 3 will vary about 10 psi.

---

All I did for the compression check was take off the ignition wires and unscrew one plug and then screw in the compression meter and press the start button for 8-10 seconds. I am not sure what position the powervalves were in but am assuming they were open.

[ 05-11-2002: Message edited by: '01gprman ]

Well after pulling the heads we have determined that it was not a powervalve because detonation caused from either a seized piston or bad crank had occured. I have taken it in to the shop and now have to wait about two weeks for the ski to be rebuilt.

d plate , compression and stock jetting caused your detonation

MD you may be correct a D-plate ski should be rejetted

quote:

---

Originally posted by Fercho:
MD you may be correct a D-plate ski should be rejetted

---

Fercho,

What should I re-jet to? My ski was running realy strong before all this happened.

Thanks for any help.

[ 05-11-2002: Message edited by: '01gprman ]