115TLRD Rough Idle and Power loss at high RPM

[jduque_99]

SCREW, AIR ADJUSTING #21 in part break down and should be under #27 that has to be removed to get to it. You did not take the carb apart and clean all passages if you did not remove any of this

Thanks 99yam40. I had not seen your last post before posting previously. Part #21 on my manual refers to the carburetor body. I did found what you refer to in the schematics from boats.net. I will target this project once again soon and will report my results.
What I was referring to not have seen before is any screws that I could have had access to them externally as referred in the other suggested post.
Would the suggested 1 1/4 turn from seated still be a good set position?

[rodbolt17]

I just posted the CORRECT spec out of the tune-up spec guide.

also posted why your most likely barking up the wrong tree with a ghost hunt.
its not the pilot air screw.
all that air screw does is allow more or less of the A/F ratio provided by the pilot air and pilot fuel jets.

to actually change the A/F ratio you either change the pilot air or pilot fuel jets.
did it all the time on OMC crossflow and loopers, still do.

never had an issue with a Yamaha carb.

[jduque_99]

should be about 5/8ths of a turn out.
the pilot fuel and pilot air jet control the A/F ratio.
all that screw does is allow more or less of this A/F mixture into the passages.
did you check the fuel pump while you were at it? they don't last forever and they hide debris.

Thanks rodbolt17. So, if I understand correctly. The Pilot Jet Plug (#11), Pilot Jet (#12), and Pilot Air Jet (#19) Should be all tight. And just adjust the Screw Air Adjusting (#20, not referred to in my manual but referred to in the schematics from Boats.net) 5/8 of a turn instead of 1 1/4 turns as previously suggested in a different thread.

Everything else is clean, hoses, fuel filter, pump, etc. But I will double check once again.

[99yam40]

Thanks 99yam40. I had not seen your last post before posting previously. Part #21 on my manual refers to the carburetor body. I did found what you refer to in the schematics from boats.net. I will target this project once again soon and will report my results.
What I was referring to not have seen before is any screws that I could have had access to them externally as referred in the other suggested post.
Would the suggested 1 1/4 turn from seated still be a good set position?

2005 115TLRD Yamaha Outboard CARBURETOR Diagram and Parts
Sorry it is #20 not 21

[jduque_99]

2005 115TLRD Yamaha Outboard CARBURETOR Diagram and Parts
Sorry it is #20 not 21

Thanks 99yam40. That is the link where I found what you were referring to in your previous post. I will take everything apart once again soon and use the settings given by rodbolt17. Will post results, or another cry for help as soon as I am done.

Once again thanks for the help provided so far.

[rodbolt17]

your getting to hung up on that screw.
at 1 1/4 turns out the engine may or may not care.
it will be getting to much of the A/F mix but most the time the average person wont be able to tell.

[99yam40]

your getting to hung up on that screw.
at 1 1/4 turns out the engine may or may not care.
it will be getting to much of the A/F mix but most the time the average person wont be able to tell.

I was just letting him know where it was and if he did not take them out when he cleaned his carbs it is a good chance all passages where not cleaned.

But after rereading his original post you are correct in that that adjustment will not cause loss of power at high RPM, but could affect the idle. Just needs to make sure all linkage,timing , and other adjustments are in spec with all passages and jets clean
Compression test would be a good thing also to make sure all cylinders are sealing properly

[rodbolt17]

spark and compression test ALWAYS come first.
no sense in handing out a death certificate AFTER you did the carbs.
and it happens.