Thread: Why do some 2 strokes do this?

I have thought about this some more.

When the item is running either two things are occuring to keep it running.

1) the airflow of the incoming mixture keeps it cool, and due to the revs the item is running at, despite being a small engine, there is enough mass airflow.
As the mixture is 'wet', that is why it is cool - lick your finger, stick it in the wind flow - it feels cool.

2) If the mixture is getting too warm, then it may be detonating a little earlier than intended, but at the high RPM the item is running, probably not noticable.
Then when the item stops running, the user cannot get it to turn over fast enough for the mixture to detonate at the same time as the spark.

As for the post with the Husqvaran motorbike, maybe laying it on it side, cools something enough to make the change - or something else

I have the ultimate cheapy chainsaw of Evilbay. No brand name other than chain saw on the box it came in. Was starting well enough, then the issues started. Was the plug. It was a Chinese brand. The local lawn mower bloke said they where garbage. As the cheap plugs age, they when hot stop sparking as the metal tongue opens enough to stop sparking. Poor quality metal being used. Put a brand name plug in ( think it was champion ) no problems since. So if you have not replaced the plug since you have brought it have a look at replacing it with a decent plug.
Cheers Hall

Have an eight HP 4 stroke mulcher,same thing,damm hard to start if it runs out of fuel,and is hot.
I have tried all kinds of sequencing,choke on or off,throttle half on,full on,prime different amounts,etc,etc.
It is bloody hard work trying to get it to go,as it is a big engine.

When stone cold will usually go second try,sometimes even the first,no worries at all.

My Echo two stroke leaf blower is the same,takes for ever to start if hot,and a PITA.Cold,goes first go.

The Honda 4 stroke mower is great,starts first go hot or cold

Maybe these engines are tuned to start when cold but not hot,or as Dave says,get a vapour lock.

Same thing with my lawnmower. Cut the back lawn no problems, stop the mower , go to the front lawn, wont start.
Looked it up on Google some time ago and its caused by a vacuum or airlock generated somewhere(carby, cylinder ?) and wont let the engine fire.
Wait until both the mower and my frustration have cooled down then away we go.
Not sure what the solution is.
Peter.

Many moon ago, a mate of mine renowned for his lack of patience and short temper, bought a new Victor mower. He brought it home and immediately mowed the front yard. It was turned off to push under the house to mow the back yard, where it failed to proceed.
After many failed attempts to restart it, he phoned the mower shop, from where he had purchased said devil.
The shop owner asked him if he had turned it on its side, to which my mate replied "I threw the jolly thing (or words to that effect) against the fence, would that make a difference?"
The mechanic was there within the hour to tune it.
The only reason he threw it against the fence was because the fence was 6' high, the intention was for it to go over.

Originally Posted by Hall

........... Put a brand name plug in ( think it was champion ) no problems since. .....................
Cheers Hall

Haven't been champs for quite a while. NGK or Bosch and you're on the money.

DL

... because all two-stroke engines share a common ancestor...






Satan.

Haven't been champs for quite a while. NGK or Bosch and you're on the money.

Ah just showing my age I guess. New it was a name brand and it did the business.
Cheers Hall