1991 yamaha txrp 200 ping at wot

[wellcraft 238]

plugs do not look like they are running hot runs fine at all other speeds just had carbs rebuilt new seals and washers. is it maybe a high speed adjustment needed possibly a wrist pin afraid to run it until i figure this out the port motor runs fine so i dont think its the fuel. if anybody had any ideas they would be greatly appreciated

[robert graham]

If it is in fact a "ping", then maybe run a tank of higher octane gas(like 93) to see if it might reduce the sound?...Heavy carbon in the combustion chamber might cause a "ping", maybe run some Yamaha Ringfree in your gas tank at the "deposit removal" dosage. Good Luck!

[wellcraft 238]

ok i will try the 93 and ringfree this weekend to see if it helps. just dont want to burn a hole in a piston or something it seems fine at lower rpms. i hardly ever floor it and it doesnt make the noise when its floored taking off the noise comes around wen i get above 5400 rpm thanks for the help

[robert graham]

Well, if it's a "ping" like in detonation or pre-combustion, then it's certainly worth checking into!...maybe an older motor has some carbon in combustion chambers? I believe about a full tank of gas with the Ringfree at "deposit removal' dosage is required for it to work...they mention that during de-carbon procedure that some spark plug fouling may occur. Don't suppose you may have gotten some old, contaminated, degraded or low octane fuel somewhere?...Let us know what you find!

[wellcraft 238]

it is possible that it had some contaminated fuel get thru the canister filter i drained the tank this year ad have not filled it up only 30 gal at a time in case i need to drain it again. the boat had been sitting for 5 yrs when i got it so i have been slowly going thru all the steps to prepare for a bahamas crossing next year. i have replaced the canister filters on both motors twice and have been watching closely to make sure no gunk has gotten in them i thing that the tank still might have had a lil varnish in the bottom. it bothers me a lil that only one motor is having these issue though. thanks for the feedback