Echo pb250

[hosocat]

I picked up an echo pb250 blower at a yard sale. It has spark, and carb seems to be working. I pulled the flywheel to make sure the key hadn't bent and upset the timing, which was an issue with some of these. My compression gauge broke, but the compression did seem low, so I pulled the cylinder. Cylinder and piston seem to be fine. No scoring. It just won't start, or even sound like sputtering. Occasionally I will get a small backfire after pulling a dozen or so times.

While I wait delivery of my new compression gauge, does anyone have any clues what this might be? I haven't checked the seals. Could bad seals make it seem like there's low compression and cause backfires?

 

[isawben]

Have you looked at the spark arrester yet? They tend to get plugged up on blowers and cause running issues. You might also check that the rings move freely in their grooves, and aren’t stuck with carbon.

 

[Chevboy0167]

Should be similar.....

 

[hosocat]

Okay. New compression gauge arrive. About 130 psi, so compression is not the problem. I put a new hipa carb on it, and spark plug is getting moist, so fuel is getting in. It will sometimes sputter and want to run for a few revolutions, then die. Is pressure checking the seals my next logical step? I have not done that before, but watched a few YouTube. Not sure about my capabilities to fabricate blocks to seal off engine.

 

[mountainlake]

Maybe the coil. Steve

 

[hosocat]

It's got regular spark. Is it possible the spark isn't strong enough?

 

[isawben]

What color is the spark?

 

[hosocat]

It's kind of a bluish white.

 

[Chevboy0167]

I have had 1 saw that showed great spark with plug out of cylinder. Install plug and no spark under compression. To be fair it was a junk china coil from the previous owner. I slapped in a used OEM Husqvarna coil and she is golden.

Try a fuel filter? Tank vent plugged? Dribble some mixed fuel down the carb throat and crank it. If it runs longer on the dribble, fuel delivery problem.

Revisit post #2. Remove muffler/spark arrester and take a look at exhaust port on the cylinder. Look wide open or plugged up by carbon?

 

[mountainlake]

Have you tried a new plug. Steve

 

[hosocat]

Yes. New plug.