1999 YAMAHA VMAX 150-Sudden drop in RPM's-Please Help!

[bmartindds]

I have a 1999 Yamaha V-max 150 with a 3-blade 25 pitch prop. It has been running great since I purchased it about a year ago, running full throttle at about 5400 RPM's and reaching about 63m/h according to my speedometer. About 3 weeks ago, I experienced a sudden drop of about 1000 RPM's and a decrease in speed to about 55m/h at full throttle. Since then, I've run it once more and I am still only pushing about 4500 RPM's and 55m/h (still running smooth and sounding normal). I was wondering if anyone had an any idea of what could be causing this immediate drop in RPM's?

[Robert]

Mine did that as well. Was running fine, just a drop in RPM's. Found the throttle cable had come loose inside the motor. Put it back in the grove, and all was well. Hope your problem is that easy to fix!

[ChrisH]

mine did that at one time also. i had forgot to put one of the plug wires on when i changed plugs. either that or you dropped a cylinder. hard to do one a 150 carb motor but im sure its possible

[Bass Junkie]

Have you checked the plugs to see if they are fouled? When was the last time they were changed?

[txmartin]

Better get that thing runnin so we can go catch some fish!

[SL190]

I have a Year 200, 150 Vmax on a SL190 Skeeter, this year it started to loose RPMs while Im running over 40 mph. I believe there is a connection, based on several occurances, between the loss of RPMs and trimming up/down. Not sure exactly what is going on but thought I would share my experience.

Patrick