Engine Grass trimmer engine not good

OldNick

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I have an MTD grass trimmer has run fine for a few years. But come Spring and the need to whack weeds, it's a bit of a mess. Under choke, it starts after a few pulls. Then as always it needs a bit of a rev under gradually decreasing choke to run , idle and respond to throttle.

But now, i
- t needs semi-choke to remain at idle, or to respond to throttle.
- it has intermittent missing at run speeds, unless (and even then) I have half choke set.
- it puts out heaps of smoke under acceleration and even at a given load.
- I can hear missing when this smoke happens brrrt brrt
- the smoking gets better as it warms, or at least as it runs under load. (if it stops, then we go through the cycle of smoke again...so it's not engine temp)
- if I try to let it idle (and that happens only with half choke and idle set really high) it idles for a while and then it starts to slow down: I can ask for power, then throttle response begins to fade and then idle slows and in the end asking for power results in a stall. buuuurgh.
- to restart I need full choke and start is instant, first pull (I wish that happened other times :) ) But we repeat the cycle.

I replaced the plug (it was very burnt and pitted). That helped but not much.

I have ideas, but I do not want to pull apart the wrong bit and waste my time and risk damaging what ain't broke.

Any thoughts appreciated.
 

ILENGINE

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I would start by checking the oil level to make sure it isn't to high and smells like gas. Then pull the carb off and give it a good cleaning and replace any necessary parts and/or replace the carb depending on cost difference between the new carb and a carb repair kit.
 

Romore

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Unlikely there is a carb rebuild kit available. A new one would be worth a try if you don't mind spending a bit of money and time on it but any more than that call it a day and replace the trimmer.
 

OldNick

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I would start by checking the oil level to make sure it isn't to high and smells like gas. Then pull the carb off and give it a good cleaning and replace any necessary parts and/or replace the carb depending on cost difference between the new carb and a carb repair kit.

Ah. Sorry. It's a premix 2-stroke motor. So no oil level. The oil I use is a Husquie one that says use 50:1 and that's what I use.

But yeah I will check out my carby options.
 

OldNick

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Unlikely there is a carb rebuild kit available. A new one would be worth a try if you don't mind spending a bit of money and time on it but any more than that call it a day and replace the trimmer.

:(. OK. Sounds reasonable but disappointing. I will find the price of a carby I was wondering about an air leak (hence needing the choke to start) but to me that does not explain the heavy smoke.

If I have to buy a new one that will be a nuisance, but it owes me nothing: it has had many hours of use; weed whacking, branch trimming, blowing stuff hedge clipping.

Thanks for the help guys. Clears my mind.
 

OldNick

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Just thought I would do you guys the courtesy of a result. Also could be useful info if a similar question is asked.

I hauled out my alternate power head, only to find that it was not too good either. I tried the leaf blower...and guess what?

Some doofus (who shall of course remain nameless) had way overdone the 2-stroke oil :ashamed:. I mixed up a new batch and everything is running sweet as.

Nick
 
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