856 Carb drain, bad fuel, clean questions

[FLtractor 78]

Afternoon,

 

Just replaced battery, fuel line, fuel tank valve, on my 856. Tractor previous owner said only used regular gas.. I’ve bought non ethanol to use from now on, but want to get carb in good shape first. 
On to rest of fuel system, being carburetor. Attached pictures of my carb. 
So I understand, take off air filter nut, then find correct socket for bottom of carb fuel bowl, take off carb bowl, drain out sediments and clean bowl with carb cleaner, hopefully gasket isn’t damage when removing. 
Then I remove choke linkage and bolts holding carb to engine? Take carb off and spray with carb cleaner in throat and jets, find small enough screw driver to fit inside jet and remove jet and needle, spray all with carb cleaner to check for debris and varnish from years of regular ethanol gas build up. Clean carb then replace on tractor as it was in reserve order? Anything else I missed or need to do differently for a better running tractor after? I believe the ethanol fuel caused my tractor to stop starting due to dirty debris carburetor. 

Edited 5 hours ago by FLtractor

[ebinmaine 75,581]

35 minutes ago, FLtractor said:

hopefully gasket isn’t damage when removing. 

 

You're headed the right General direction. That carburetor gasket. It's going to be trash. That's not negotiable. Get a good kit from kohler. I refuse to use aftermarket. I can send you the numbers when I get home.

 

Great carburetor cleaning is all about having great patience. After you clean it, do it again. And then when you're done with that, do it again.

 

I use an ultrasonic cleaner to do mine and whoever sends me a carb. Feel free to do so.

 

I also use about two cans of brake clean.

 

After a complete disassembly including all of the screws, spray every orifice inside outside backwards forward up down left right and then back again every direction. It's not the least bit complicated. But you definitely want to be thorough.

[Handy Don 15,073]

Unless or until you have reason to suspect the needle valve seats, I would not mess with them. Most carb kits do not include replacement seats and removing them (if, in fact, they are removable) can cause more damage than help. Needles yes, seats no. The “jets” in small engine carbs tend to be precision holes drilled strategically in the bore. Ultrasound and copious carb clean (applied while wearing protective gear on hands and face) is the “go to” method. 

Cleaning (sometimes more than once, twice, or three times) is adequate unless serious fuel contamination has irreversibly damaged the carb body--in which case a new carb is likely needed.

BEFORE removing needle valves, gently close them and write down the exact number of turns needed so you can put them back where they were upon reassembly!

Edited 16 minutes ago by Handy Don

[ri702bill 10,521]

Ah, yes. Fun with Carter Model "N" carbs....

Just a few things...

 

Do use an ultrasonic cleaner with the carb disassembled. You do not have to remove the choke plate & shaft. If you do - watch out for the detent ball & spring!!!

Look at the bottom of the inside of the bowl. Severe pitting from ethanol fuel is a fuel leak about to happen. Best to replace it.

The high-speed adjusting screw is hollow. There is an external hole to this center passage and an exit hole near the tip. This entire passage MUST be clean, as it is the air bleed for the high-speed air / fuel mix. If left dirty, adjusting the mix may not be possible.

Once cleaned and reinstalled, the real "fun" is getting the transition off of the idle circuit to the high-speed circuit correct without a stumble or hesitation. Really stubborn ones require a load (mower or other belt driven implement engaged) to do it right. Do this with the engine warmed up, choke off & air filter installed.

Final note - it is better to have the mix on the rich side than on running it lean.

 

[ineedanother 1,807]

Good information here but I'll add IMO you can't effectively clean a carburetor without removing and replacing the welch plugs. They're cheap and easy to replace. They cover drillings in the carburetor body that you really need to be able to spray cleaner through or to have uncovered when you submerge the body in an ultrasonic tank (also highly recommended and relatively cheap at harbor freight or online). 

 

DonyBoy is a good source of information but I don't subscribe to his removal method. I never drill through them, I just carefully drive a scratch awl through and pry them out. Clean the carb, set the correct replacement plug in the milled body and set it (gently) with a blunt punch. If you foul the plug just pry it out and set another until you get it right. Really easy once you've done a couple.