Bvm200, moderate use, started fine last time. Now, no spark; new plug, new gas.

When was the last time you did a tune up (spark plugs, spark plug wires, distributor cap and rotor)?

Make sure that the gasoline if new. You can spray a small amount of starting fluid into the carb to help start the motor. Make sure that you turn the switch to the run position.

Hi Mike:
It's trying to make you crazy.
I have a model YT4000 and it is a PITA to start when cold.
I pull the air filter, toss in a bit of gas to prime it, and it starts instantly.

I'd suggest that you give yours another try. 3 or 4 times of a couple of seconds each. If it doesn't go, pull a spark plug and see if it is wet or dry. Wet indicates getting gas but no spark. Dry indicates not getting gas.
While you have the plug out, check the spark... Hot & blue.
Hope this gives you some more to work with.

.025-.030

I know you mentioned the EGR valve has been replaced, but you may have a bad 'new' part. I know the car is electronic, but has anyone checked its ignition timing (timing belt been looked at, I know it only has 77k on it). Is the fuel pressure regulator OK and it vacumm supply?

Unable to crank? Do you mean unable to start?

If you leave gasoline inside tank over long period of time, that will 'gum-up' and ruin carburetor.
To prevent problem, put additive in gasoline or empty gas from tank:: under gas tank should be a hex bolt that holds up gas filter > loosen bolt and drain gas.

Starting the engine:
Take off air filter and spray WD-40 directly into carburetor.
Start engine, engine should fire on the WD-40 accelerant.
If engine fires but does not keep running, try spraying WD-40 into carburetor continuously to see if you can keep engine going.
If engine stops each time after it no longer gets WD-40, then carburetor is bad or gasoline not getting to carburetor or gasoline is bad.
Try fresh gasoline.
Do not turn small engine on side or upside down or oil will get into carburetor.

Check gas supply: Go to gas filter under gas tank. Pull loose rubber hose that connects to carburetor and see if gas comes out rubber hose.
If gas is flowing to carburetor, then carburetor is gummed up.
Small engine repair might suggest 'gum out' or have other suggestions ... but you may need a new carburetor

If engine will not fire on WD-40
If engine will not fire on WD-40 at all, then spark coil may be bad or exhaust port is clogged
Check screen that covers exhaust >> is it covered with carbon and dirt or can air pass through it easily?
Check spark
Remove spark plug
Put spark wire back on spark plug
Hold spark plug by rubber spark cap so hands don't touch metal part of spark plug
Touch spark plug threads against hole where spark plug was removed >>> metal to metal so it conducts electricity
Pull start cord and look for sparking between spark plug threads and metal of engine (don't look at the spark gap ... look where metal meets metal
If you have no spark, the spark coil is bad >> time for estimate from small engine repair shop or get your part number and order replacement

ignition coil may be damp and tracking,ht lead tracking,plug u/s look along those lines

Starting problems with 2-cycle engines are usually traced to fuel line/filter clogging due to jelling of the fuel mixture while the engine is idle. Best fix is fuel mix pretreatment with some kind of gas saver in the gas can. Marine grade additives are the best, such as 2+4 gas treatment. Now your stuck with pulling the fuel lines and blowing them clean. If the carb has a primer bulb, you can sometimes force the fuel through, but a complete cleaning is in order. Pulling the plug and putting a few drops of fuel mix directly into the cylinder head, (or in the air intake), can sometimes get the motor to fire. This proofs the problem as being fuel starvation.

Check for a plugged fuel filter and defective fuel lines. Make sure the carburetor fasteners are tight. Check for spark at the plug--it should be blue and snappy with a new plug. If ok, squirt in some fuel mix in the plug hole, replace the plug, and see if it will pop a couple of times. If ok, make sure the primer bulb draws fuel into it after several pumps. If still won't run, remove the lower chamber of the carburetor and check the diaphragm for flexibility and no holes. Hope this helps!

the bvm 200 model has a 25cc piston and ring the rings are infamous for getting clogged and baked into theyre seat,this creates a compwesion problem and it will not start,gets fuel spark but without compresion it'll just not run or start,if careful you can remove the piston soak it with ring atached in carb cleaner and get it springy again or replace the ring with a new one it has a 1.353 (34.38)mm bore and a ring thikness of .061 hope this helps