Small engine ultrasonic carb cleaning tips?

[JOEPRO]

I have a 1970s Stihl 045 carb stripped down and it's not that dirty.






I will scrape off that last gasket before putting into ultrasonic cleaner.

Do you run this for about an hour say with hot cleaning fluid? Must I remove the small aluminium gally plugs or leave them alone? Not keen on taking them out if I don't have to. New gasket kit coming in post not sure of the exact contents.

I haven't cleaned carbs in the ultrasonic before so any tips or "don'ts" appreciated.

 

[8ob]

If you look at the proper carb build kits they include all the brass/ali plugs, for a proper clean these should be removed, on some there is a small piston hidden behind these plugs. Can’t really do a thorough job without stripping them down to bare bones.

Bob

 

[bricol]

If liquid can't get in, then the ultrasonic effect won't get there either.

If you can rotate it around and ensure all the air is out, liquid is in everywhere, then the effect will work - but if loosened crap can't get back out . . .

Obviously cleaning effect is somewhat reduced on internal passages compared to direct action on external surfaces.

 

[JOEPRO]

If you look at the proper carb build kits they include all the brass/ali plugs, for a proper clean these should be removed, on some there is a small piston hidden behind these plugs. Can’t really do a thorough job without stripping them down to bare bone.

Bob

So I may be better waiting on the kit to get here later in the week and take out any small plugs in the kit.

Those are so small - are there special tools for re seating them? Or even for getting them out without causing damage.

 

[Migmac]

I don’t take the plugs out, only the stuff that comes off easily. I use Allendale carb cleaner solution, heated up and give it a couple of 20min cycles in the U S cleaner. Only had problems with one carb doing it this way and I think it was my fault I had problems. I’ve only seen one YouTube taking the plugs out and that was because he knew there was an issue with the piston pump thing. After mine have been through the U S cleaner I dip them in petrol

 

[JOEPRO]

This is a screenshot from the ebay listing. It is a genuine Tillitson kit.

I see a mesh and silver foil cap in the pics. (Wrong names but hopefully it makes sense)

So I will try to carefully remove those with a micro screwdriver and dunk it in US cleaner.

I will also then blow around the drillings with a can of carb cleaner to ensure all is flowing as it should afterwards. Then await the kit to arrive and put it back together.

I did take lots of photos of the gasket positions etc when taking it apart and also noted the L &H screw adjustment turns last night. So after work today I'll see how I get on!

Edit: correct name is Welch plugs.

 

[Migmac]

The mesh is just a filter, comes out easily. The new one goes in with a push from the blunt end of an appropriate sized drill bit. I guess the plugs will go in with a similar approach

 

[GRW]

I did the carb off my dinky Honda EX1000 suitcase generator.
I'd tried all sorts of other ways (aerosols, compressed air etc) inc stripping out the jet and emulsifier tube - several goes and the genny would still hunt unless on part choke.


Stripped Inc removing the brass jet and emulsifier tube, and a session in my 15L US in very hot water (around 70c) with the bits in a Pyrex jug in the centre, with hot carburettor cleaner in - did the trick.

The carb galleries doing the pilot jet work etc are so small on these dinky engines that it really doesn't take much oxidisation or fuel varnishing to have a big effect. You can get away with much more on a bigger carb I think

 

[frank horton]

I just take of the easy stuff and give the card a couple of max time cycle in the SC….
Turning the carb a few times during the cooking…..
Only once did it not work…..
Just bought a cheapo carb from China. No more probs….
Have found getting the correct carb repair kit a bit diff so off to China for another carb…
Must have bought / fitted around 15 cheapo's and never had a bad one YET…
Ps. Only use proper cleaning solution

 

[JOEPRO]

Sorted!

I WFH Mondays and skipped lunch to clean the carb when the repair kit turned up early.

I found that when blowing through carb cleaner after the US there was debris stuck in the low idle jet. So definitely important to use carb cleaner and compressed air to blow out the drilings and confirm they are clear.

Putting saw back together now.

 

[angellonewolf]

and

 

[JOEPRO]

and

Starting up easily with a wiff of a he-man pull. Needs tuned and there seems to be a small air leak if some sort. I have a new intake boot ordered and will replace the crank seals too since they are circa 50 years old at this point.

It made its first chips in around 10 years tonight. Powerful saw. Maybe not quite the same high chain speed as my MS391 but feels like it's got more torque than it and would cut at around the same speed overall. Very impressed with it. Indeed I prefer the chain speed of this saw as the MS391 sometimes feels a bit too fast!

 

[JOEPRO]

I have since successfully returned 2x more different original Stihl carburettors to perfect working order by ultrasonic cleaning them with the solution noted in post #1 and using aftermarket gasket / diaphragm kits.

This is the only way to go if you have any doubts over a carburettor. With a proper US clean and fresh parts there is no reason why it shouldn't run perfect again in most cases. (Excessive shaft wear or other reasons are outliers of course)

I noticed one other sign of carb trouble on small engines is leakage. If you are inspecting a carb and it has fuel dribbling out or it's wet with fuel then it needs a refurb.

Very happy now I am now having repeatable success in rebuilding original small engine carbs.

 

[Keithmac]

Main thing with Ultrasonic Cleaning is getting all the water out afterwards, a good airline and plenty of GT-85 does it for me.

Nice to see your have had good results.

 

[angellonewolf]

I'm not a pro or any thing near

Just played with small engine stuff for a while

It's rare it needs more than a clean and carb kit


Half are just old fuel left in unit