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Dominick, Marine Mechanic
Category: Boat
Satisfied Customers: 1009
Experience:  25 Years Experience as Mechanic, 20 Yrs Boat Yard Owner/Mechanic, Factory Certified
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I have a 2001 Yamaha wave runner xlt1200 and have problems

Customer Question

I have a 2001 Yamaha wave runner xlt1200 and have problems with the engine gurgling at mid range then it clears after several minutes and runs great until I run it at mid range then the same thing happens. I had the carbs rebuilt last season and run 91 octane non methanol gas. Someone said it could be the valves by the exhaust which get clogged? Any suggestions
Submitted: 5 months ago.
Category: Boat
Expert:  RSRBOB replied 5 months ago.
Hi and thank you for your question.The first thing we should do is a compression test to ensure all cylinders are in good shape. If you do have a power valve stuck open, a compression test will show that.I would suggest getting away from the 91 RO fuel and going back to 89 octane. Yamaha designed that engine to run on regular and it truly runs best on regular in stock configuration. Unless you have a high compression head on it, at the least it is a waste of money and it could also cause a decrease in performance because it is going to run richer than regular. Yamaha tends to jet their carbs towards the rich end of the jetting fringe and running too high of an octane can push it past the fringe.The next potential problem could be a leaking needle and seat. A good test would be to start with a new set of spark plugs, take it out and ride it and once it starts gurgling, hold it there for a good 30-60 seconds, then stop and pull the spark plugs out and look at them. You are looking to see if one is darker than the other 3. If one is, that is the problem cylinder/carb. It is crucial to get accurate results from this test that you don't cut any corners doing it. First, a spark plug cannot be cleaned. It sounds like you are fouling plugs and once a plug fouls, it is never 100% again. The porcelain insulator becomes contaminated and saturated and there is no undoing that. Also, make sure you are running resistor spark plugs. You have a digital ignition on your engine and it is very sensitive to RFI (radio frequency interference) signals that non resistor plugs do not suppress. RFI signals can trigger false signals to the engine control module and cause misfires.Do you have a receipt from the carb rebuild last year to be able to tell me exactly what parts were replaced? With 900 hours and being 15 years old, components are definitely going to be showing wear and tear.If the fuel filter looks clean, I would not worry about that either.What brand of oil are you running? Stock injection system or premix, and if premix what ratio?One last question, are their any modifications to the ski, anything that is not exactly the same performance wise as it was when it left the factory?Thanks,RSRBOB
Customer: replied 5 months ago.
Thanks Bob the carbs were all cleaned out of slugs probably from old gas sitting in the machines. I bought it used. The reason i run 91 octane it doesn't contain methanol and not prone to absorb water. I'm running stock injection oil. With new plugs it runs fine for a while. I have good compression on all cylinders. I will check the plugs to make sure they're resistor plugs
Customer: replied 5 months ago.
I meant sludge in the carbs
Expert:  RSRBOB replied 5 months ago.
Thank you for the additional information.Please understand that in using this medium to request assistance to repair and to be able to guide intelligently without wasting your time, I need very specific answers to my questions. Often, the answers to my questions can vary greatly so I don't suggest repairs or even in depth diagnostics until the basics of the diagnostic process is covered. Trust me when I tell you, anything I ask you to do is exactly what I would be doing to your ski if you brought it in for me to work on. Suffice to say I do not like guessing at what something means or what a person meant. I fully realize that you have the best of intentions to provide meaningful information, but, more often than not, I need information to help you that may seem useless or pointless to you. Also, many times too I have suspected a certain problem with a unit only to have the owner disagree with me and assure me it could not be that problem, when in the end that is exactly what was wrong with it. The reasons behind certain requests and explanations for all possible results generally are too lengthy to go into here.Having said that, do you have access to the equipment necessary and inclination to provide a current compression test of all 3 cylinders?Also, as far as the carb work last year, do you mean there were no internal parts replaced on the carbs during the process of cleaning?I can appreciate the fact that you want to avoid ethanol fuel, but the fact remains the engineers designed the engine to run on 89, and it truly runs best on 89. I would suggest as an alternative running 89 and any one of the many fine fuel stabilizers on the market. With ethanol being so prevalent now, chemical companies have had sufficient time to develop products that significantly reduce, if not eliminate, the problems ethanol creates.I did get that you are running the stock oil injection, but did not see you mention what brand of oil you are running. Do you stick with one brand or do you tend to switch from time to time?The engine is definitely fouling spark plugs, as supported by your statement about running well on new plugs, for awhile. This is a band aid on the problem I would like to help you resolve.Thanks,RSRBOB

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