Weed whacker rough running / stalling problem

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Sep 9, 2015
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Hey all!

I have a 2010 CubCadet weedwhacker/trimmer that I fixed this past winter that's been out of service for the past 5+ years. This used to be my father's favorite trimmer but the upper driveshaft housing/tubing broke where it snap/clicks into the lower housing. He stopped using it for a Hitachi WeedWhacker/trimmer which I got one too and they are nice and durable!!!

He said I could have the CubCadet and we both had the idea to lend it out to people who could use one. So I fixed it over the winter and decided to give it its first test today.

Well, it ran rough, and could basically only idle, emitting white smoke (could have had blueish tint but I didn't really take special note). Whenever I applied throttle it would increase RPM but the whole trimmer would violently vibrate/shake, and if I gave it enough throttle it would completely stall out.

I thought it was due to old gas so I let it idle out until it stalled from no more gas. And so I put in my two stroke gas in it but it still ran the same. Idle pretty rough, violently vibrate/shake with a little throttle, and stall out with a lot of throttle.

The head does spin freely, I even disconnected the head of the trimmer and rotated the driveshaft with my fingers and could feel no clear resistance or jumps/skips etc. Rotating it by hand it was smooth.

My two stroke gas did sit over winter but my Poulan Leaf blower, Hitachi string trimmer, my restored 2000 Barracuda Weed Eater, and my chainsaw all ran fine on the same gas.

The gas is 87 octane and ratio is 50:1. The CubCadet calls for 40:1, haven't read the manual yet if it called for higher octane. I didn't think there would be too much harm or difference running 50:1 in it just to see if it could trim some lawn edges so I'm here asking you guys what could be the potential issue?

Should I take the spark plug out, sand it off a little to see if there is even a minor amount of improvement?

Thanks for the help!
 
Originally Posted by nwjones18
Time to clean out or replace the carb.


*Sigh* I was REALLY REALLY hoping that was not the case lol
 
Since the last issue was mechanical damage to a rotating assembly, I would look there first. Check the trimmer head for anything funny, or out of balance. Check the clutch and make sure everything is lined up correctly.
 
Originally Posted by JeepWJ19
Originally Posted by nwjones18
Time to clean out or replace the carb.


*Sigh* I was REALLY REALLY hoping that was not the case lol


We all do hope that's not the case.. haha. I'm sure the fuel lines will need to be replaced at the same time. The little carbs are usually very cheap on ebay/amazon.
 
Originally Posted by ripcord
Since the last issue was mechanical damage to a rotating assembly, I would look there first. Check the trimmer head for anything funny, or out of balance. Check the clutch and make sure everything is lined up correctly.


The driveshaft itself was fine, it was just the upper tubing/housing that wouldn't snap into the lower housing/tubing. It has one of those stupid push in type bolts/heads that clicks it into place so it's attached to the lower housing. Apart from that, no drive line damage or replacement was needed.
 
Originally Posted by nwjones18
Originally Posted by JeepWJ19
Originally Posted by nwjones18
Time to clean out or replace the carb.


*Sigh* I was REALLY REALLY hoping that was not the case lol


We all do hope that's not the case.. haha. I'm sure the fuel lines will need to be replaced at the same time. The little carbs are usually very cheap on ebay/amazon.


Yes, my restore of the 2000 barracuda leaf blower took a new carb. The most painful part was a discontinued carb and had to eyeball a $14 cheap one off Amazon that looked similar. Said screw it, pulled the trigger and for the most part it was a direct fit, just a minor design change.

Wasn't looking forward to doing that again lol
 
Originally Posted by Randy_R
Bad gas. What did you eat?



Buffalo chicken, black beans, and rice. Yum.
 
Originally Posted by JeepWJ19
Originally Posted by ripcord
Since the last issue was mechanical damage to a rotating assembly, I would look there first. Check the trimmer head for anything funny, or out of balance. Check the clutch and make sure everything is lined up correctly.


The driveshaft itself was fine, it was just the upper tubing/housing that wouldn't snap into the lower housing/tubing. It has one of those stupid push in type bolts/heads that clicks it into place so it's attached to the lower housing. Apart from that, no drive line damage or replacement was needed.

Can you try to run it without the attachment to see if the vibration goes away?
 
Originally Posted by ripcord
Originally Posted by JeepWJ19
Originally Posted by ripcord
Since the last issue was mechanical damage to a rotating assembly, I would look there first. Check the trimmer head for anything funny, or out of balance. Check the clutch and make sure everything is lined up correctly.


The driveshaft itself was fine, it was just the upper tubing/housing that wouldn't snap into the lower housing/tubing. It has one of those stupid push in type bolts/heads that clicks it into place so it's attached to the lower housing. Apart from that, no drive line damage or replacement was needed.

Can you try to run it without the attachment to see if the vibration goes away?


Yes, I will try that for you tomorrow. Thanks for the suggestion
 
I went through these kind of issues with my weed whackers for years.....last year I bought a 40V battery powered one and I'll never go back to gas powered.
 
I wish you were closer as I have two Snapper whackers I'd give you for parts.

Ethanol is the culprit in my case. Runnings and Tractor Supply sell a regular pre-mix and a pre-mix called "mechanic in a can" that has worked for an old chainsaw.
That might help your whacker as it still runs. Apparently this stuff eats the ethanol goo and cleans the lines.

For me, my company uses Dewalt everything, so I bought a Dewalt electric weed whacker and never looked back. It has two speeds and the battery lasts a long time.
 
Originally Posted by Zaedock
I wish you were closer as I have two Snapper whackers I'd give you for parts.

Ethanol is the culprit in my case. Runnings and Tractor Supply sell a regular pre-mix and a pre-mix called "mechanic in a can" that has worked for an old chainsaw.
That might help your whacker as it still runs. Apparently this stuff eats the ethanol goo and cleans the lines.

For me, my company uses Dewalt everything, so I bought a Dewalt electric weed whacker and never looked back. It has two speeds and the battery lasts a long time.


Thanks, I have a tractor supply right down the road so I will make sure to take a look next time I'm out. This will probably be one of the first things I use as it's one of the simplest.
 
Originally Posted by gonefishin
I'm not saying this is your issue but it never hurts to check the flame suppressor screen. I had one that was running rough and tried all the obvious stuff to fix it. Finally figured out the screen was so clogged it caused it to run rough.

It doesn't hurt to check it/clean it. https://www.ereplacementparts.com/r...tor_Screen_on_a_Small_2Cycle_Engine.html


Noted. Thanks for that, I didn't even know such thing existed. I'll try the other easier solutions first, as I do not own a blow torch currently
smile.gif
 
I remove the spark fire arrested from behind the muffler.

The vibration may be caused by too much string out or too large a diameter string.
 
Originally Posted by JLawrence08648
I remove the spark fire arrested from behind the muffler.

The vibration may be caused by too much string out or too large a diameter string.


Interesting. Then thatll be tested with the previous mention of checking with the head off the trimmer.

I thought I measured the length of the string to what the manual said, I'll have to double check. I also made sure to wind the string in the direction that it told me too.
 
Originally Posted by JeepWJ19
Originally Posted by nwjones18
Originally Posted by JeepWJ19
Originally Posted by nwjones18
Time to clean out or replace the carb.


*Sigh* I was REALLY REALLY hoping that was not the case lol


We all do hope that's not the case.. haha. I'm sure the fuel lines will need to be replaced at the same time. The little carbs are usually very cheap on ebay/amazon.


Yes, my restore of the 2000 barracuda leaf blower took a new carb. The most painful part was a discontinued carb and had to eyeball a $14 cheap one off Amazon that looked similar. Said screw it, pulled the trigger and for the most part it was a direct fit, just a minor design change.

Wasn't looking forward to doing that again lol


Usually the carbs are either walboro's or zama's and they have a model number stamped on them. I fixed up an old pair of weedeater hedge clippers and I was able to find the correct carb using those numbers. Was around $20 and came with fuel line, filters and a spark plug. i did have to adjust the mixture on the carb to get it to run right though.
 
Sorry for the late reply!

Finally got it fixed today. Bought a cheap carb kit off Amazon. Replaced the fuel filter, fuel lines, air filter, primer bulb, and carb.

Ran it today and it works about as good as I'd expect.

There's still some shimmying/vibration at lower speeds. I forget if I tested it with the head off or not. But at typical RPM it was smooth.

The last thing is the spark plug. It was really black. There was also wet black chunks - unburnt fuel or carbon???? Going to be replacing that soon as well, as the spark plug that came with the carb kit was too tall.

Thanks!
 
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