150BT backpack blower

Oddjob said:
I think I solved it. I had been thinking that it was a fuel starvation issue but I was wrong by 180 degrees. It was running too rich.

This carb has just one adjusting screw. I reset it to the factory setting and the blower started easily and ran well. Then it began to bog down again, so I tried giving it more fuel via the priming bulb. That made things worse, but it gave me an idea that the problem may be too much fuel rather than not enough. Because it ran well at start-up at the factory setting I didn’t think that it needed much adjusting. I was wrong. I leaned it out and it really came to life and it stopped bogging down when fully warmed up. The factory setting was 1 1/4 to 1 1/2 turns. My final setting after backing it off from peak power was a tad less than one turn.
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It is amazing on handheld equipment how small adjustments on high and low mixture screws can affect the performance. On small engines, the carburetor set up correctly and having the air/fuel mixture is crucial.
 
This why a tach is very useful in adjusting these carbs. Most are usually tune to peak power and then enriched to slow down around 50-100 rpms and this is done after the unit is warmed up a bit. Tuning by ear just doesn't work here.
 
StarTech said:
This why a tach is very useful in adjusting these carbs. Most are usually tune to peak power and then enriched to slow down around 50-100 rpms and this is done after the unit is warmed up a bit. Tuning by ear just doesn't work here.
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Can you recommend a particular tach?
 
Tiny Tach II is one but I am currently using one from Husqvarna that will shutoff the screen when not in use as to extend the internal battery life which is not replaceable. Both are good up to 20,000 rpms.

I prefer the direct induction type over the wireless ones. Plenty of copy cats tachs out there too that would work well. Just make sure you read the reviews especially the bad ones.
 
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