2011 Yamaha 65 Jet cuts out

[WomaninCamo]

The jet has fewer than 100 hours on it - recently started cutting out at RPM's around 3000. Any ideas?

 

[99yam40]

Re: 2011 Yamaha 65 Jet cuts out

Most problems end up fuel related, but you need to troubleshoot and test all of the things you can to find out what the problem is.
Compression, spark, timing, and fuel pressure/vacuum

 

[WomaninCamo]

Re: 2011 Yamaha 65 Jet cuts out

Thank you for the suggestions - the dealer tested the fuel system says it isn't there...they hooked it up to their fuel system and it did the same thing. Dealer is telling me it isn't the motor - it runs just fine. Also, they did a diagnostic test and said it didn't throw any active faults and the history was clean. They talked to Yahaha and Yamaha told them to check the bearings in the bearing carrier. I am having a hard time believing the issue is with the bearings - the boat gets greased each time it is used - really. The boat was just in for 100 hour maintenance - comes back and now this. Logically, it does not make sense - at least it doesn't to me.

 

[99yam40]

Re: 2011 Yamaha 65 Jet cuts out

maybe you need to explain a little better about what you call cuts out.
I took it that the motor was missing or turning off

 

[WomaninCamo]

Re: 2011 Yamaha 65 Jet cuts out

Sure thing - we're running up the river at 3500 to 4000 RMP going along just fine then it sounds like the engine does not get gas for a split second then comes right back. The dealer first said is was a mechanism that stopped the motor from overheating, so they checked the thermostat, pulled the impeller, etc. They found some debris in the telltale and told us this is what the problem was - that this debris was causing the engine to overheat. Well, they tested it after they put it all back together and it continues to do the same thing. This is when they told us they talked to Yamaha and Yamaha said to check the bearings. I think if it were the bearings we'd hear it right? Does that explanation help?

 

[99yam40]

Re: 2011 Yamaha 65 Jet cuts out

I am not that knowledgeable about jets as I have not worked on them before, but it sure sounds like a fuel , spark problem to me. If bearings where a problem locking/ binding up things up I would think it would not get better all of a sudden

not sure what the motor is (carbed/injected, 2/4 stroke)as you did not post a model #, but either way monitoring fuel pressure, spark while problem is happening should show something if it was a problem them. Fuel does not throw codes and I do not know if loss of spark would either