Hello. I own a Genata GT250L-RE, 4-stroke 2008 model, and Im having engine problems. I assume the problem is in the carburator.
I have read almost every single thread in this forum and googled for about a month, but without any positive results.

I have bought a new spark plug.
I have cleaned, and air-compressed the entire carburator.
I have tried with a different battery.
I have tried adjusting the two screws in almost every possible option.
I have refilled the fuel tank with new fresh gasoline.
I have checked (not sure what its called) the black rubber ring thats between the carburator and the intake, which is fine.

After all this work, it still sounds like this: YouTube - Genataa GT250L-RE fusk.

My carborator looks almost identical to this: View image: Japanese Keihin Carburator.jpg

Im all out of options here and I beg one of you to please help me.
Any help at all would be deeply appreciated.
Thanks.

 

Welcome to the forum lukteper !

The majority of these are jetted very lean from the factory...I would be curious as to how many turns out the fuel screw is? (the screw on the bottom of the carb) it should be in the 1.5 to 2.5 turns out range...Id start at 2 turns and try to get it to idle with the other screw....Does it seem to run better with the choke on or partially on? If so it more than likely could use some bigger jets...

 

hello and thank you for answering.
i figured out that the vacuum hose was leaking so i replaced it with a new one.
Now it runs much smoother and it even idles without choke, something its never done before.
But it still runs like crap. It gets too much air. When I give it full throttle fast, it just dies. Ive tried to adjust the screw at the bottom of the carburator 1.5 - 2.5 turns out, but what does this screw do? I mean whats the difference when the screw is all the way in, and all the way out? It doesnt seem to make any difference whether its all the way in or out.

So far Ive tried with pretty much every possible setting, but it still acts like its getting too much air.

And by the way, when it comes to technical issues with engines and such, my skills are very very limited. Words as "jets" are foreign in my vocabulary and Im from Norway and I didnt get the best grade in English class.

Once again thank you very much for answering

 

I forgot to mention that it doesnt seem to make any difference whether the choke is on or off, When the engine is cold. BUT when it is hot it cant run without choke at all.
The carburetor is the exact same as the one on the picture (DeKni, standard of Japan, PZ 30).
But arent there a page that describes the specifications and settings for my carburetor?

 

I also think it's a jetting problem, The jets regulate the amount of gas as to give the correct quantity to mix with the air that will be different at all elevations. Not sure at what elevation you are at but your jets may not be the correct ones at your elevation.
This may help show you how it all works inside there!

http://www.usaatvs.com/pdf/Carbureto...Principles.pdf

 

The jets are small brass like bolts with holes in them...the larger the number on the jet, the larger the hole in the jet...you have 2 jets in the bottom of your carb...under the float bowl cover...the one in the middle is the main jet...and the one off to the side of it is the pilot jet..

As for the fuel screw...the more you turn it out the more fuel the engine gets from idle to approx 1/4 throttle...after that its pretty much the main jets job..