2004 FX HO problem to get to top speed and top RPM

olehen said:

Newb, not mechanically educated but did some research prior to post this thread.
My FXHO has 70 hours worked very good since day 1 till now and since 2 days I cannot go more than 8000 rpm and max speed at 38-40 mph. Used to get into the 54 mph.
I checked on the forum and will go through some basic checks: Will check and change this week the spark plugs. I checked the impeller though the inlet and there is no seaweed of sand. I could not check the impellers itself but will do it.
Engine is running fine as usual. I am not on L-mode (I locked it, unlocked it and get the 2 beep for the regular mode).
Is anybody had similar issues and fixed ?

thanks

Click to expand...

I have a 2003 Yamaha FX1100 HO and have had the same issue three times, low power on take off and top speed of only 40 mph or so. First time out last year it did it but came out of it about 10 minutes into the ride. I later took it to an independent shop because it was starting hard and they changed the spark plugs. Then the low power issue happened again a few weeks later so I took it to Yamaha who also changed the plugs and said one of them was seized and had not been changed for quite a while, so the first shop had only changed 3 out of 4 plugs. Ran fine the rest of the year. Had it winterized at Yamaha last fall and first time out this year had the same low power issue. The Yamaha shop said it's possible that the fogging oil from the winterizing fouled a plug (which would explain the issue at the beginning of last year.) I decided to check things out myself this time and found that when Yamaha winterized it and fogged the cylinders they forgot to reconnect coil wire #4. Good news is with two machines the only issues I've had were plug related which is an easy fix. I plan to just change plugs in both machines at the beginning of each year to avoid the fogging oil issue and plugs going bad and ruining a weekend.