FSIB20 Honda engine

[Ty Korrigan]

Hello,

 My FSI B20 grinder has a Honda GX390 engine.

Recently it has begun to struggle under load, coughing sooty exhaust and difficulty picking up, as though the choke is part on.

I've ordered a fresh air filter, checked the carb bowl for muck (clean)

It starts well enough, ticks over as usual, just bogs down under load.

 Any pointers appreciated.

  Regards

     Stuart

[Mick Dempsey]

Head gasket?

 

[Dan Maynard]

I think @doobin might say don't mess around just stick a new carb on it.

[pleasant]

I would say the same. Just stick a carb on

[spudulike]

If you are up to it....take the carb off, remove the float bowl, unscrew the main jet and then remove what I refer to as the "emulsion tube" or nozzle and make sure the jet is clear and the holes in the emulsion tube are clear.

The emulsion tube is a light push fit but can take a bit of removing - watch the Youtube vids for tips.

I have just done a neighbours troublesome hunting mower and this was the issue.

Lastly, check the float bowl sits level with the housing of carb where the bowl sits when the carb is held upside down - this makes sure the needle and seat are OK.

Or just fit a new carb

[woody paul]

Are Rotor bearings ok.

[spudulike]

And make sure the air filter is clean as a blocked air filter is the same as engaging the choke!

[Ty Korrigan]

1 hour ago, spudulike said:

If you are up to it....take the carb off, remove the float bowl, unscrew the main jet and then remove what I refer to as the "emulsion tube" or nozzle and make sure the jet is clear and the holes in the emulsion tube are clear.

The emulsion tube is a light push fit but can take a bit of removing - watch the Youtube vids for tips.

I have just done a neighbours troublesome hunting mower and this was the issue.

Lastly, check the float bowl sits level with the housing of carb where the bowl sits when the carb is held upside down - this makes sure the needle and seat are OK.

Or just fit a new carb

 

Who are you anyway and what the f**k do you know about engines....?

 😁

   Thank you, I'll give it a wang and buy a carb off Amazon as a back up to my butterfingered efforts.

 

[adw]

What is this obsession with replacing carbs, it has to be the top spare part claimed for under warranty, this i also heard from Honda during some training, black smoke from the engine is running rich, so air filter as suggested, carb flooding.

[spudulike]

1 hour ago, adw said:

What is this obsession with replacing carbs, it has to be the top spare part claimed for under warranty, this i also heard from Honda during some training, black smoke from the engine is running rich, so air filter as suggested, carb flooding.

I have to say that I agree. I must have purchased around 6 carbs in 7 years or repairing kit on a daily basis so hundreds if not thousands of machines. Most are fixable and if you know what you are doing, it is a relatively cheap repair compared to a typical £120 new carb.

My weakness is to keep going where I should throw in a towel but manage to fix most to the customers relief.

Difficult to recommend a definite fix from a distance but as we have both said...air filter is a possibility.

Worth looking to see if the unit has an automatic choke as the mower I was working on did as if this auto choke has failed, this would cause it to run rich. Honda use a wax type auto choke to open and close the choke and it is embedded in to the cylinder behind the carb and is heat activated so if the machine is warm, the choke should fully open. Probably a manual choke I would imagine though.

Edited September 21, 2023 by spudulike