Need Help with a Small Engine
- Thread starter NETWizz
- Start date
- Joined
- Feb 6, 2025
- Messages
- 54
What makes you think the jet is removable? It probably isn't.
- Joined
- Feb 6, 2025
- Messages
- 54
No adjustment screw for the idle jet is typical these days of emissions carbs. The EPA thinks that since not everyone is knowledgeable with how to adjust fuel / air mixture correctly, it'll ban the entire population from making adjustments whether the people know how or not. The idle jet is probably fixed meaning it's not removable, but the main jet is removable. You would never need to change your main jet unless you're having running issues while the engine is under load.
#7 probably is probably a cover for the fixed idle jet. Your next step would be to remove that screw and take a peak down in there to see if you find a tiny little hole. Your next step after that would be to find out the diameter of that tiny little hole which is commonly called an orifice.
https://www.yamahapartshouse.com/oemparts/a/yam/5c4f5ba887a86609d0b4de24/carburetor
#7 probably is probably a cover for the fixed idle jet. Your next step would be to remove that screw and take a peak down in there to see if you find a tiny little hole. Your next step after that would be to find out the diameter of that tiny little hole which is commonly called an orifice.
https://www.yamahapartshouse.com/oemparts/a/yam/5c4f5ba887a86609d0b4de24/carburetor
Last edited:
And the saga continues. I was able to get one (1) stud out by backing up one nut to the other.
The other one went really bad and I think it stripped the threads in the stud except the nuts no longer work on the first already removed stud anymore, so it is likely actually the threads of the nuts.. LOL. I just cannot win!
The double-nut shortcut to remove studs failed me on the ohter stud!
Okay, so I decided to tear it apart because I at least need to lift the gas tank to get the carb out to even figure out what I am doing next.
Anyway while I ordered both studs AND both nuts so whatever threads are buggered up I can just easily replace those parts so they thread by finger again... Here forward, I will just tear it down and NOT try to double-nut it! I ALSO ordered a new pilot jet. Being this is 2019 and the unit I have was manufactured many years later, I am hopeful the jet size may just be bigger.
The other one went really bad and I think it stripped the threads in the stud except the nuts no longer work on the first already removed stud anymore, so it is likely actually the threads of the nuts.. LOL. I just cannot win!
The double-nut shortcut to remove studs failed me on the ohter stud!
Okay, so I decided to tear it apart because I at least need to lift the gas tank to get the carb out to even figure out what I am doing next.
Anyway while I ordered both studs AND both nuts so whatever threads are buggered up I can just easily replace those parts so they thread by finger again... Here forward, I will just tear it down and NOT try to double-nut it! I ALSO ordered a new pilot jet. Being this is 2019 and the unit I have was manufactured many years later, I am hopeful the jet size may just be bigger.
- Joined
- Feb 6, 2025
- Messages
- 54
What's in the way of the carburetor sliding off the studs?
Inverter and gas tank . You can or slide it off completely unless you pull enough to lift the fuel tank.
It may be clogged. Take it out and clean the jet. Also spray cleaner through the side to the little holes that go into the side of the venturi past the throttle plate. Don't drill anything out yet. If it is either run 3400 rpm or stall you have basically no low speed fuel. The whole point of an inverter generator is it runs much less than 3400 rpm with light or no load.
- Joined
- Feb 6, 2025
- Messages
- 54
The screw that The_Eric is referring to is #7 on the drawing. Take it out with a straight slot screwdriver that fills the slot completely.
You wouldn't be drilling it out. You would be reaming the hole with special jet reamers. Drill bits don't get the hole concentric.
The 1st step now is to remove that screw to see if the screw itself has a hole through it, or if it's covering a hole.
After that, if the screw is indeed covering a hole, you'll need to find out what diameter the hole is. You would do that with jet wires.
Last edited:
Can you link me to some jet reamers and jet wires?
I already ordered a second jet too from the 2019 diagram… I am hopeful that it will be larger.
Either way if I have two the same size I can drill one and if that is a mistake switch back to u do the change.
You're probably not wrong, but in my experience a drill bit of the appropriate diameter will still do the job.
Great news is I got the stud situation sorted. I needed one (1) stud and two nuts. Now the nuts spin on by finger again.
Turns out double-nuting can blow out the threads on a stud and both nuts when it goes wrong. I actually had to tear the generator apart this far to get the carburetor out safely.
Anyway, now on to troubleshooting the lean condition in the next segment.
One new stud and two new nuts... a Lesson Learned!
Turns out double-nuting can blow out the threads on a stud and both nuts when it goes wrong. I actually had to tear the generator apart this far to get the carburetor out safely.
Anyway, now on to troubleshooting the lean condition in the next segment.
One new stud and two new nuts... a Lesson Learned!
Here is the carb cleaning video. I used the B12 Berryman's. I cleaned it yesterday. I have full patency through each circuit. If I spray the cleaner, it comes out somewhere else for every hole!
I also replaced the low speed jet with the 2019 Pilot Jet part 7PC-E4A42-18-00 just because I bought one, so if I mess it up reaming out the jet, I have a backup jet.
My video quality could be better; I am learning. Apologies.
I also replaced the low speed jet with the 2019 Pilot Jet part 7PC-E4A42-18-00 just because I bought one, so if I mess it up reaming out the jet, I have a backup jet.
My video quality could be better; I am learning. Apologies.
I have that same generator, and after sitting for too long with non-stabilized gas inside, the pilot jet plugged up. The pilot jet comes out external to the carb. I removed it, and then had to find a small stiff wire, pulled from a wire brush, and after pushing that through the small orifice, the carb was running perfect again.
So does that screw have a hole all the way through it or is it a tapered needle type? Typically moving the screw, if it's the needle type, will control how much fuel enters the carb. Just make sure to turn this screw in and count the turns until it seats lightly. You can then turn it back out the same number and then make 1/4 turn adjustments (in or out) until it stops the lean misfire.
I have a feeling that the round brass piece just to the left of the jet screw is a cover over the low speed jet, and the screw controls how much air is introduced into the circuit. Commonly, you drill a small hole in that cover, twist in a screw a couple of turns, and pull the cover out. Depending on how that is set-up, it could be a removable jet inside, or a fixed orifice. Either way, if thats the case, make sure its clean. Just remember, you'd have to source another cover if you take this one out.
I have a feeling that the round brass piece just to the left of the jet screw is a cover over the low speed jet, and the screw controls how much air is introduced into the circuit. Commonly, you drill a small hole in that cover, twist in a screw a couple of turns, and pull the cover out. Depending on how that is set-up, it could be a removable jet inside, or a fixed orifice. Either way, if thats the case, make sure its clean. Just remember, you'd have to source another cover if you take this one out.
Well. IT's FIXED!
The jet is NOT tapered and NOT adjustable. It has a hole through the screw. The part in #7 on the 2019 catalog is NOT the same pilot jet the carburetor came with. The 2024 Yamaha EF2200IS has smaller holes in the pilot jet!
Just swapping to that new jet I ordered clearly is making this machine run so much better. It is night and day!
I will post another video soon, but it is at least 99% better. Might not be 100% in that it is close to where it could misfire if it loses any more fuel, but it can run for 10 minutes plus, take a load and unload and not be missing more than maybe once when it changes RPM. Then it steadies itself within +/-10 RPM and holds.
It is running VASTLY much better now.
Good deal, and good fix! Surprised the screw has a hole in it and is exposed to outside, unfiltered air. To me that would subject it to something getting inside and plugging it up. Well now that you know how it all works, if it starts running rough, or lean misfiring again, start with cleaning out (or heck, replacing for that price) the jet screw. Seems like this is where the problem was, and not necessarily dirt or a clog, but just not big enough to deliver sufficient fuel. Again, good job!.
Similar threads
- Locked
