2 stroke not starting

rich13348

I bought a 2 stroke McCulloch hedge trimmer this weekend. I cannot get it to start even tried brake cleaner (don't have carb cleaner ATM) down the spark plug hole and at it still didn't start. Spark plug is sparking when I turn it over.

If it's not starting with a highly volatile spray like brake clean is there much hope for it?

DB1904

rich13348 said:

I bought a 2 stroke McCulloch hedge trimmer this weekend. I cannot get it to start even tried brake cleaner (don't have carb cleaner ATM) down the spark plug hole and at it still didn't start. Spark plug is sparking when I turn it over.

If it's not starting with a highly volatile spray like brake clean is there much hope for it?

New or used?

daveyjp

If used and its had petrol sat in it for any length of time it may need more than a squirt of brake cleaner.

Mustie1 on youtube is worth a watch, pleny fo small two stroke videos on there.

rich13348

DB1904 said:

rich13348 said:

I bought a 2 stroke McCulloch hedge trimmer this weekend. I cannot get it to start even tried brake cleaner (don't have carb cleaner ATM) down the spark plug hole and at it still didn't start. Spark plug is sparking when I turn it over.

If it's not starting with a highly volatile spray like brake clean is there much hope for it?

New or used?

Used. The fuel line had popped off so had to put that back on but otherwise looked on but had sat with fuel over the winter according to previous owner.

rich13348

daveyjp said:

If used and its had petrol sat in it for any length of time it may need more than a squirt of brake cleaner.

Mustie1 on youtube is worth a watch, pleny fo small two stroke videos on there.

I have seen a few of his videos. Will have to have a refresher session and pop the carb off and give it a good clean.

facade

From my experience with 2 stroke motorcycles years ago-

1) the petrol must be really fresh- like straight out of the garage. Last years petrol wont work, it just wont.

2) change the spark plug. It doesn't matter how well it sparks outside the engine, or how well you've cleaned it. I used to warm them up with a blow lamp and they still wouldn't work. If it won't even try and go on carb cleaner I'd suspect the plug.

Ensure that all the jets are clean in the carburettor, and there is no water or dirt in the tank.

There is always the possibility that it is just worn out and has no compression, and that is why it was up for sale.

Mutton_Geoff

The carb will be gummed up, you mustn't leave fuel in these overwinter, especially stuff with ethanol in it. You can buy a carb kit from Ebay, there is a little plastic gasket with a bubble that acts as a fuel pump, I bet this is stuck. When you strip the carb, you'll find a sticky varnish over everything, this is the ethanol in the fuel reacting with the plastics.

When I had two stroke tools, I used to buy Stihl fuel, it cost a fortune but never caused issues with these tiny two stroke engines.

Megaross

Clean the carb up, clean the plug, replace the petrol.

Fuel, spark and compression. Verify the first two are good and clean, if you have fuel and spark you're down on compression - luckily 2 strokes are very easy to rebuild.

If it's been run without enough 2 stroke oil in the fuel before compression being down is a very real possibility but don't leap to conclusions on it just yet.

rich13348

Compression seems good by the amount of effort it takes to pull over. I will get a spark plug and clean the carb and see how it goes.

I bought fuel on Saturday for it so fuel is good. I removed the old stuff left from last year by previous owner.

I will let you know the outcome.

Goudy

If you search Youtube you'll find videos of Carb teardowns on these.
Stale fuel will block the jet and the jet on these is tiny to start with.

Soak in carb cleaner and use compressed air through the jet.
If you hold the jet up to the light you should be able to see through it.

Also clean the inlet "needle" valve, if it's gummed up it won't allow fuel into the carb.

If you really need to poke the jet with something, use a strand of cooper wire out of a spare bit of cable.

rich13348

I took the carburettor apart and there is a screw on the bottom of the carb when really didn't want to come out. When I did get it out there was a pile of black stuff in the hole and on the bottom of the screw. When I cleaned the black stuff off the screw there was a small hole with a sprung ball bearing that when depressed allows fluid through to holes on the sides.

Likewise when I cleaned the black stuff out of the hole there is a smaller hole leading into the Venturi.

It looks like fuel can get from the one side of the carburettor into that hole that leads into the Venturi.

My question is this hole meant to be blocked with black stuff or is this not right?