Hi peeps! New to this forum.
My Grandsons 50cc Kazuma was running great about 2 weeks ago, put it away, gas off.
He came over last weekend and the think just constantly fouled the plug with fuel.
Excellent spark,tried a hotter plug.
It was cold out so we tried getting it warm in the garage to o effect.
I just pulled the carb, checked needle and seat, floats look fine, thoroughly cleaned it and the air filter, still no go.
Any thoughts or ideas on this?
Actually been a great lil quad for my 4yr old gson.
THX!
Mess

 

An overly rich mixture is usually down to a stuck choke, blocked air filter, loose jet, or stuck float. The carb would be dribbling fuel out of the overflow, on most machines, if the float/needle was stuck. I don't know what type of carb the Kazuma 50 has, but the electric choke type gives excess fuel until a heater coil in the choke mechanism has warmed up, so it's default setting is to give too much fuel.

 

Merryman, first off thanks!
It is a manual choke, 50cc Chinese engine. Basically a Honda 50,
Did checks on all jets, cleaned, blew out and checked float.
As b4 , excellent spark, won't start, no indication of even trying.
In a warm garage.
Starting to consider something internal?
Cam timing?
Intake valve?
Took off inspection/ adjustment cover and is moving.
Where do I go from here? ( no Alan Parsons Project Pun intended, LOL)

Thanks!
Mess

 

BTW, no fuel dribbling out of overflow, air filter cleaned and oiled.

 

Check valve clearances, if they close up they get bad to start, and a big clearance indicates a stuck valve. If that isn't the problem, check compression, it needs to be over 90psi for easy starting, though I once got a Honda 70 with less than 20psi and it ran!

 

Merryman, is this done with adjustment at the intake valve? Sorry not too familiar with the 4 strokes. What is the procedure of checking them ?Thanks
Mark

 

Probably best to check U tube videos. The inlet and exhaust valve caps need to come off, then you get the engine at top dead centre on the compression stroke, (don't forget the piston is at TDC on the exhaust stroke too). There is a mark on most flywheels, I have a feeling it is a bit vauge on the Honda 50, but near enough is good enough. My preference is a light down the plug hole, feel compression escaping as the piston rises, then watch for the piston getting to the top, with the light. Then you check the clearance between rockers and valves with a feeler gauge. Don't know what a 50 should be, the Honda 90 is 0.002" for both.

 

Thanks merryman! Gonna give it a try when my compression tester comes!
Mark

 

You don't need a tester to set the valves.