Completely blocked blind passage in carb...how to clean?

[cheetah chrome]

Bottom carb on a 2002 150 TXRA. The passage I cannot get to unclog is between the common fill passage and one of the needle valves. The passage cannot be accessed to get a tool in there for manual removal. When this passage was manufactured there is a brass press in plug where the tooling entered the cast.

So far I have tried:
CRC carb cleaner
CRC brake cleaner
Acetone
Long (multiple intervals summing up to hours in total) heated ultrasonic clean in simple green at full strength.
Long (multiple intervals summing up to hours in total) heated ultrasonic clean in LA's totally awesome degreaser at full strength.

Pulling vacuum on the needle valve location at the clog I can get a very slow bleed through of fluid or air so at best the clog is 'pourus'.

Carb came off a neglected motor that sat for years so I'm not dealing w a ill' varnish or gum....this looks more like scaling (a good analogy would be mineral deposits on a leaking plumbing valve).

Otherwise, the rest of the carb is spotless. Is there a solvent that will break down dried ethanol/water/scale? Any other tricks to get the cleaned out?

[boscoe99]

Can you provide a photo of the plug?

For some Yamaha carburetors a small brass ball is used to permanently plug a passageway. That ball can be extracted to facilitate the cleaning process.

The hole is drilled, tapped and a screw and washer is then used to plug the hole. After the carburetor is ultrasonically cleaned of course.

A brass plug is also used to block access to the mixture adjustment screw on a number of Yam carburetors. It is a snap to remove that plug.

[cheetah chrome]

I was thinking remove the plug, clean, tap, n replug too being the amount of elbow grease it too to get the rest of this carb clean. Plug:

[cheetah chrome]

Passage runs parallel to where I'm holding the dowel (from the needle valve seat to the common passage feed by the fuel inlet pipe.

[boscoe99]

When you're down to nothing you got nothing to lose.

I would drill that plug out. Then re-clean the carburetor and hope for the best. A counter sunk screw might be needed to seal the hole.

Also, if all else appears to be lost you might want to try using some CLR to clean the carburetor. It will remove scale buildup up that results from lime, calcium and such.

Yamaha offers a really effective carburetor cleaner but I don't know that it will work against what you are facing. Desperate times call for desperate measures.

Good luck.

[cheetah chrome]

Easy. In case anyone else runs into this issue. Dimple the ball, start w a small bit n go slow.

[cheetah chrome]

Eureka, once through increase bit size until you basically have a small thin brass ring in there.

[cheetah chrome]

Use a dental pick and pull out the ring (no after pic it twanged off to somewhere else in the garage).

[cheetah chrome]

Clean. All this crap was in that short passage....again neglected motor but yikes. Carb is back in the ultrasonic to get any fillings out from the surgery. The original bore was intact removing it this way and measures .159". I order 5/32" and 3/16" brass balls from McMaster Carr. I'll see what size the 5/32nds actually measures but that actually might yield a press fit w/ increasing the hole size. I'll post an update w/ the outcome next week. Thanks,

[cheetah chrome]

Fin. The 5/32nd brass balls came in on the low side of there tolerance and we're basically a slip fit. I had to drill out the hole and press in the 3/16 guy. Still pretty easy. If anyone else has to do this the McMaster pn for the brass balls is 9617K34....or pm me. They come in packs of 100 so I have 99 left over. Carb is back in the U/S cleaner for a quick flush out of and fillings from me drilling the cast. Thanks.

[Blackhawk36]

Did the carbs work well or did you need to replace them.

[rodbolt17]

an easier method you ask?
simply research the tech bullitens.
drill the carb as the bulliten suggests.
clean the passage.
later carbs were drilled,tapped and capped.
but there is a bulliten on drilling the carb passage to clean the needle seat passage.

[fairdeal]

an easier method you ask?
simply research the tech bulletins.

Is there a way for an individual Yamaha owner / DIYer to do that?

[boscoe99]

Is there a way for an individual Yamaha owner / DIYer to do that?

No. Not really. You could always ask a dealer and see if he will provide a bulletin to you. But without a list of bulletins you don't know which ones you want to be looking at anyway. They go all the way back to 1984.

Yamaha US' philosophy seems to be that owners should not be doing other than routine maintenance on a motor. If more than routine stuff is needed then the motor should be taken to a Yamaha dealer.

This is part of the reason why Yamaha US stopped allowing dealers to buy and sell YDIS software to owners.

Heck, there are even internal bulletins that Yamaha won't let their dealers have sight of.

[99yam40]

Heck, there are even internal bulletins that Yamaha won't let their dealers have sight of.

Who gets to see them then?
just the engineers that write them