YT175 problems

[Rustala]

Got my hands on this YT175, never put my hand on a two stroke before other than 50cc in my youth so pretty new to this.

At first glance it needed some carb cleaning, new cylinder/top end gasket and some welding to the exhaust due to massive leaks..

It is idling just fine now and pretty easy to start, but as soon as i touch the throttle it just bogs down and more or less starts to four-stroke. My first thought was crank seal and perhaps carb issue, so new seals and a after market carb but no difference and now i all out of ideas where to start. May this be caused by some electrical problem? CDI?

Hope I have made myself understood to some extent, English is not my native language as I come from Sweden.

[fordsoll]

I find that if its a spark issue it won't start easy or bog down, its possible but there are a few other things that you can try before replacing the cdi, coil or stator. While I am talking about spark check the kill switch bypass it temporarily even I have found problems like yours that a killswitch solved. What colour is your spark plug? Have you tried a new spark plug? What about the plug wire and resistor cap?

I'm guessing that it is running rich, what is the needle height set to? Should be at the middle, there are 5 positions. Also check the choke going into the carburetor, there is a brass and rubber plunger that needs to seal, make sure it is in good shape and the spring is intact. You can bypass the choke by disconnecting the cable end from it and keeping the spring in place and putting it back in. If it is not sealing you will suck in excess fuel, possible that at idle it can't suck in enough extra fuel and as the engine speed increases it starts to suck in fuel from the choke. If you haven't already clean the float needle and check the height of the float, it needs to rest parallel with the gasket surface of the carburetor.