Jump to content
jason110

Off topic - 2 stroke engines

Recommended Posts

Hi all. 

Hope no one minds an off topic conversation. I’ve a cheapo hedge trimmer / strimmer 2 stroke power brush cutter type thing.

Recently got it out of the shed and, fresh petrol in it fire it up no issues, thing is the damn thing won’t rev up, it will idle fine but won’t rev up the way. it just stalls on me. It sounds like fuel starvation. 

Am I correct in thinking that taking the carb off and soaking it in white spirits and then blowing it out with air will get the varnish off it? 

 

Share this post


Link to post
Share on other sites

Yeah, it'll be running too lean on the main jet. Whip the carb off and clean it up, it's probably full of old two stroke oil after the petrol evaporated off. 

Share this post


Link to post
Share on other sites

I'm not sure how effective white spirit is but you can buy carb cleaner in an aerosol can which is good at dissolving the varnish and old petrol gum. I'm sure Halfords sell it, toolstation used to but had no stock in my local branch.

 I have to admit that I had the same bother and I got so fed up at having to investigate the carb on my old 2-stroke strimmer I went and got a battery strimmer.

Share this post


Link to post
Share on other sites

This is where it’s worth considering buying an ultrasonic cleaner ...

Share this post


Link to post
Share on other sites

Thanks gents.

Job for this morning then! Annoying because I’m back from work and the garden needs a serious hair cut! 

Thought about an ultrasonic cleaner, we have two in work, one big, one small. both are used for cleaning pretty everything you can think of. 

Share this post


Link to post
Share on other sites

Could you strip it and take it into work ? 😊

Share this post


Link to post
Share on other sites

If only! There’s all sorts in the workshop, but she is liquified natural gas carrier currently off Argentina. 

Got it going with some high flash point solvent spray I had in the shed, stripped it down, literally sprayed it everywhere and then blew it with the air. Works fine now. 

  • Like 2

Share this post


Link to post
Share on other sites

Had the same trouble myself, i cleaned mine with brake cleaner which was to hand. The problem is leaving fuel in the carb, once I got mine going again, I pulled the feed pipe off the side, pumped the bulb dry and ran it till it stopped, that should stop it happening next time I hope?:unsure:

Share this post


Link to post
Share on other sites

Just be careful, as of course when a 2 stroke runs out of petrol it runs out of oil too....

Share this post


Link to post
Share on other sites

I have a Stihl 2 stroke petrol cutter which is an absolute b*tch to start as well.

 

I shall strip that apart and get the carb cleaned.  The only downside is the entire cutter is caked in concrete dust over the years of it's life so it'll be a large clean up operation as once i begin removing the carb, i'm bound to get carp falling into places it shouldn't be!

Share this post


Link to post
Share on other sites

Funny this topic should crop up as my Stihl FS450 brushcutter is playing up. I tend to run the tools over winter too so fresh fuel gets flushed through regularly but this thing has started to loose power and die when hot. I put a new carb on it a couple of years or so ago and it's never really been right. Instead of having two adjustment screws the new car only had one. New carb, filter, plug, gaskets and priming bulb ready to be fitted soon.

 

Share this post


Link to post
Share on other sites

If dying when hot, could well be the magneto,especially since you have a new carb.

Share this post


Link to post
Share on other sites
On 5/6/2019 at 1:25 PM, Bowie69 said:

If dying when hot, could well be the magneto,especially since you have a new carb.

One on order ;)

Share this post


Link to post
Share on other sites
Posted (edited)

My large chainsaw died recently in a similar way. It got to the point that i couldnt start it in the end. I tried all of the obvious. Turned out the piston had melted itself so it has turned into a full rebuild! The whole thing has taught me to whip the exhaust off and take a peek at the condition of the piston before going too far ordering parts. I thought my spark was breaking down as it was there when the lead was connected to a plug outside of the machine, so changed the plug and ordered a new magneto but neither were the problem.

Edited by reb78

Share this post


Link to post
Share on other sites
10 hours ago, reb78 said:

Turned out the piston had melted itself so it has turned into a full rebuild!

Wow, I didn't realise Land Rover made chainsaws 🤣

Share this post


Link to post
Share on other sites

Pistons melt in petrol engines because of weak mixture Rich, you must have had a air leak somewhere.

Mo

Share this post


Link to post
Share on other sites

Another thing to remember regarding two stroke motors is to always pre mix you fuel and do it accurately, use a measuring jug for your fuel and a large syringe for your oil , guesstimates are bad for your engine 

Share this post


Link to post
Share on other sites
On 5/6/2019 at 3:36 AM, Anderzander said:

Just be careful, as of course when a 2 stroke runs out of petrol it runs out of oil too....

Never had a problem running my saws (chain saws and conrete saws) "dry" for years. AND ive never had a problem with bad fuel or gumming up either.

After I have finished using the saw for the day, and know I wont be using it for at least a couple weeks. I start, idle, stop. Drain all the fuel I can. Start and let run. When it gets to the point of starting to run funny due to fuel starvation, I play with the choke to get it to run more as much as I can. All at idle. Until its out.

 

I bet my life there is still a film of fuel oil mix on the crank/rod bearings and cylinder wall.

Ive had a saw sit for over a year after this technique, put fresh fuel mix in, choke, 3 pulls and it starts.

 

I only use high grade fuel (no ethanol) and high grade oil.

Share this post


Link to post
Share on other sites
On 5/7/2019 at 10:55 PM, Happyoldgit said:

One on order ;)

 

Duly fitted along with a new carb, gaskets, primer t1t, fuel pipes, pickup filter, air filter & plug. Ran ok but then the shut off microswitch in the handle failed so it's gone to a loving new owner. It was an ex contractor machine anyway so could be termed as well run in. I subsequently invested in a nice, shiney new Stihl of similar size.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy