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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
 

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Do all the basic checks. Compression etc and write back. Also check fuel pressure with a gauge. Replace the plugs first though. It wont be anything in the pump causing it to only rev to 8000. Possibly cam position sensor.
 

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I changed the spark plugs and the jetski is moving fast again and rpm back to top as well.
The air filter was clean so I did not change it. total was a 30 usd fix. thanks for help.
 

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Don't forget to change the Air Filter! Over and Over I see these yamaha ski's loose top end speed because of a clogged and moldy air filter, I know on some of the ski's the dealer wants like $120.00 for the filter, but you can get them online cheaper, R&D makes them $75 or so, buy one and save some of the stress! Maintaince Maintaince! Plugs are cheaper than having a ruined weeked, so is a air filter!
 

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I changed the spark plugs and the jetski is moving fast again and rpm back to top as well.
The air filter was clean so I did not change it. total was a 30 usd fix. thanks for help.
I have exactly the same symptom. My 04 FX HO Cruiser ran fine last time out. And yesterday it would only pull 8000 rpm's and 38 mph or so. I too double checked to see if I had it in the L mode. It ran so smooth, that I didn't suspect it would be a spark plug. I checked the air fliter, and it was like new. And, was about to pull the fuel pump to check for a plugged fiter screen. And, if that was ok, check for a restriction in the exhaust. If new plugs fixed yours, I am definitely going to give that a try first.

I've been an auto tech for many years, and my experience led me to not suspect plugs. But, live and learn. I hope it fixes mine also.
 

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I have exactly the same symptom. My 04 FX HO Cruiser ran fine last time out. And yesterday it would only pull 8000 rpm's and 38 mph or so. I too double checked to see if I had it in the L mode. It ran so smooth, that I didn't suspect it would be a spark plug. I checked the air fliter, and it was like new. And, was about to pull the fuel pump to check for a plugged fiter screen. And, if that was ok, check for a restriction in the exhaust. If new plugs fixed yours, I am definitely going to give that a try first.

I've been an auto tech for many years, and my experience led me to not suspect plugs. But, live and learn. I hope it fixes mine also.
Make sure to post with an update after your plug change.

THANKS
 

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Make sure to post with an update after your plug change.

THANKS
I replaced the plugs, and bingo it is running full power again. Thanks for the help guys. I would never have suspected it was running on only 3 cylinders it was still so smooth. I've got about 140 hours on mine (04 FX HO Cruiser). Looking at the removed plugs it appeared #1 was the one it was missing on.
 

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We have a large 3 seater Yamaha and my friend insists on swapping out the plugges after every 2 trips out.
The one time we cleaned the plugs and reused them was the time the unit bogged down alot and had a hard time running top speed.

Has anyone found Bosch Platnum plugs that fit? I was thinking they would not foul as easily and spark alot hotter.
 

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I have a 2008 FX Cruiser HO. It ran fine last year prior to servicing. This year, I brought it in for a service and I am suspecting they didn't change my spark plugs or something because every time I've used it this year, I only top out around 48mph. Last year I had no problem hitting 62 or 64 mph. After reading this, I would have NEVER thought about spark plugs..but I'm definitely going to change them and will post back if it helps. I sure hope it does :)
 

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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
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.
 
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