# Echo PB-500T backpack blower wont stay running or accelerate



## Gaspowered (Sep 25, 2020)

Hey, I am currently working on a 7 year old Echo PB-500T and it's being a royal P.I.T.A. I worked on it for a friend two years ago, it had a bad bog and all it needed was a metering diaphragm and a carb adjustment. It ran fine, and I came back to the shop where he works about a year later after I worked on it and he said it wouldn't stay running and had no power. Sure enough, I took it back to my place and it would start, run for about 5 seconds and wouldn't accelerate. It also smoked pretty bad, even off of a 40:1 mix. I decided to throw a $15 eBay China carb on it and it didn't seem to change. I made sure the metering lever was set correctly before installing it. Beforehand I did change the fuel filter, lines, spark plug and intake gasket. I also checked the spark arrestor screen and exhaust port and they were both clean. What I mean by that it won't accelerate, it's not a "lean bog," it just won't accelerate at all and eventually dies. I made my own adjustment tool for those awful tiny "single d" adjustment screws and adjustment barely changed anything, I set both needles at 1 1/4 turns. The first thing I thought of was weak spark, I removed the coil, tested it and it's a bit past the recommended resistance rating, but not too far. It has nice blue spark at the plug. This thing also has about 120 pounds of compression, so that's out of the picture. I sprayed starting fluid around the intake while it ran for 5 seconds, and it didn't seem to change. This thing has the "stratospheric scavenging" system with three reed valves, and I'm not too familiar with that. I'm not sure if that would be affecting it. Last thing I can think of would be a bad crank seal but this thing isn't that old and doesn't have too many hours on it. It does start after dying though, but it still doesn't want to run. Any help would be appreciated. Thanks.


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