# 30cc Craftsman backpack blower carburetor adjustment



## AmsoilBergie (Nov 5, 2008)

I have a 30cc craftsman backpack blower. I have used it about two tank fulls of gas in it last year worked great. Store it for the season (with no fuel). This year I was using it for about 10 -15 minutes and it started to sputter. I change the fuel witch I knew it was good, still the same ran like $&!+! So after going all over the place to Find a plug, I found a new $6 plug at Napa, it still sputtered the Manual said to have the carburetor adjustment done by SEARS or a qualified shop.

My question is how is this done I don't see an Air fuel mixer screw I can work on small engine So how do I do a carburetor adjustment


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## geogrubb (Jul 28, 2006)

Post the model number so we can chase down the carb to see if it has any adjustments, it's most likely a zama or walbro. Have a good one. Geo


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## AmsoilBergie (Nov 5, 2008)

*Model #316.794990*

The model # is 316.794990 I have also noted that it will work on 1/2 to 3/4 throttle but then sputters Thanks!


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## geogrubb (Jul 28, 2006)

All I find is that it is a MTD/Ryobi with a MTD part # carb which means it could be anything they could buy cheap, if it has no obvious adjustment screws your options are limited. If it will run at idle I would suggest mixing a half and half mixture of fuel and Sea Foam or Chevron Techron, enough to idle for about 30 minutes, let it set and idle(do not rev it up while this using this mixture) to see it the combination will clean some varnish and restore some flexiblilty to the diaphram, also check the fuel lines although it is new you have no idea how long it was setting in a box somewhere. Deteriorated fuel lines create more problems in small engines than any other single issue. Have a good one. Geo


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## hankster (Jan 1, 1998)

The carbs on those blowers are not adjustable. One thing you can try is cleaning the carb (along with geo's other suggestions). Next to try is just take the metering arm and bend it up a bit, this will give it a bit more fuel per stroke.

The last thing we have found is a bad ign. module. I know this sounds crazy, but if you take a gap type spark detector and hook it between the spark plug and the ign coil (the part that plugs on the spark plug) try and run it. You may find the engine runs normally. Our only solution we have found for such a situation is replacing the ign. module.

Note: we have different theories on why putting the spark detector in-line with the plug makes the engine run correctly but no one knows for sure.


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## AmsoilBergie (Nov 5, 2008)

I will try to clean the carb! I do think it will be the ignition module/ coil thats why I change the plug This is one of those times, that I wish I would have bought the insurance!


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## 30yearTech (Sep 14, 2006)

hankster said:


> I know this sounds crazy, but if you take a gap type spark detector and hook it between the spark plug and the ign coil (the part that plugs on the spark plug) try and run it. You may find the engine runs normally. Our only solution we have found for such a situation is replacing the ign. module.
> 
> Note: we have different theories on why putting the spark detector in-line with the plug makes the engine run correctly but no one knows for sure.


I was told by factory service rep, that running an inline spark tester slightly retards the ignition timing by delaying the spark, and on some engines with a slightly bent flywheel key this will smooth the running out. Not all engines are sensitive to small changes in ignition timing, but 2 cycles more so then 4 cycles.


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## hankster (Jan 1, 1998)

Interesting. We kind of thought that the extra gap caused the spark to have a higher voltage but yours is as good as any


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## AmsoilBergie (Nov 5, 2008)

Gap type spark detector, where do i get one?

I took it to Sears, They took it under manufacturer warranty. I will wait for three week and let you know


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## AmsoilBergie (Nov 5, 2008)

Sears said that it was the primer problem??? It runs now, just that at 7/8 to full throttle it misses once every 45sec or so


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