Ideas why my leaf blower engine slows after 10 minutes?

[wahoowad]

I have an older Homelite Backpacker gas powered leaf blower with a 25cc engine. It sat unused for several years but I pulled it out and quickly got it running yesterday. It hasn't seen much use and is still very clean and almost like new.

It started right up with some fresh gas/oil and new plug! I let it warm up and then checked the carb adjustment screws but it ran right with the original settings. I proceeded to use it for a good 20 minutes of continuous leaf blowing which suggested to me it was not gunked up. After 10 years I was feeling like I finally got my money out of something.

At the end of 20 minutes it started to slow. I thought it was out of gas so took a break, but it had plenty left and all I did was fill it back up. I go back to using it. After another 10 minutes it starts to slow again, eventually bogging and dieing. I wait a few and it starts up and runs fine, until it slows after another 5 to 10 minutes. A common tip is to check the carb bolts in case it is vibrating loose, but mine are tight.

My theory is that my chainsaw gas/oil mix of 50:1 was not providing enough oil and the unit was overheating. But the manual calls for 50:1. My next theory is the valve in the gas cap isn't working - how do I check that?

 

[velvetfoot]

I let my leaf blower sit with gas/oil in it and it got gunked up. Would run very crappily. Not the same symptons as yours-crappy from start, would run a little better, then crappy again, etc. Works fine after cleaning the carb. I bet you'll wind up having to do that.

 

[Jags]

With a backpack style it is a bit more difficult (maybe employ the help of friend or family) - but the obvious way to check the cap is to crack it open when it starts to run like crap and see if it improves.

 

[Thislilfishy]

Carbs carbs and more carbs!

Likely a carb cleaning is needed. Also, I had a similar issue and had to replace the primer bulb and fuel lines. All these items are easy to find. My issue turned out to be the primer bulb though, it would prime okay, but then bleed air into the lines, slowly starving the engine until it stalled. I don't think I got 10 minutes of run time though, closer to about a minute really.

Ian

 

[wahoowad]

Replacing the fuel lines worked. Gave me an opportunity to put in a new filter too. I also fiddled with the breather in the gas cap and don't think it was breathing. I got it working. Could have been that too. The leaves keep falling so should have a chance to run it good in a few days.

I'll also take a close look at that primer bulb. Thanks for the tip.

 

[Thislilfishy]

No worries, I scratched my head over it for weeks. Finally, for $5 I replaced the bulb and all was well.

Ian