New (old) 2 stroke strimmer

[AVI_8]

Chinese carbs are not the best, any time (rare) I’ve ever had to replace a 2 stroke carb I get a Walbro carb to replace the Chinese unit because trying to find the correct gasket for a Chinese carb is like plucking a tooth from a hen.

A bit like replacing the air filter on my chainsaw, cheap chainsaw, cost £70 has worked brilliantly from day one, 20 inch bar, done loads of cutting and has worked faultlessly, but can I find a correct fitting air filter …..er no, measure the same and physicaly look the same but are dimensionally slightly differently so the cover won’t go on. Machine won’t die though I must have been lucky buying one made on a Monday morning as opposed to a Friday afternoon like most Chinese goods.

 

[julianf]

I feel a bit more active today so went and had a look at the strimmer.

Looks almost brand new (as in no real use) but age problems -

Tank inside is pretty clean aside from bits of severed tube. Air filter spotless.

It is a b&q generic brand -

I strongly suspect the unit has had no more than a handful of runs from new. Compression is good.

I've not measured the tube yet, but, visually, it looks like about 3mm od and 1mm bore (smaller bore than I expected) and, curiously, even though it's all fallen apart, it's soft like silicone tube.

The priming bulb is stuffed.

I've not been on eBay yet but I assume generic priming bulbs will be common place. I guess I'll replace that and the tubing and see what happens then. It's all I can do at this stage, right? Or should I take the plug out and squirt some fuel in at this point?

Thanks to all for the comments.

 

[Pete.]

If you fire some fuel into the inlet and it does fire at least you know the ignition side is working.

 

[julianf]

If you fire some fuel into the inlet and it does fire at least you know the ignition side is working.

When you say "inlet", speak to me like an idiot - are we talking under the air filter, or down the spark plug hole?

And, roughly what sort of quantity? I'm assuming straight petrol will be fine, not a mix (I won't bother with s mix if I can avoid it before I get the replacement parts)

Thank you.

 

[Pete.]

Yep a small syringe full of neat fuel straight in the hole under the air filter where the air gets sucked in. Give e it a couple of pulls and it should fire up then die out.

 

[julianf]

Yep a small syringe full of neat fuel straight in the hole under the air filter where the air gets sucked in. Give e it a couple of pulls and it should fire up then die out.

Thank you.

Ill give it a go in a bit.

 

[Ton-up]

Just take the air cleaner off and spray some brake cleaner in the hole. After a couple of pulls it will fire and run for 5 seconds or so.

 

[Nomad]

I'd not try to fire it up on neat petrol - I did that with a 50cc moped, it fired up fine, ran for 2 seconds on the fuel I'd suqirted into the carb mouth, then refused to fire again.
I'm sure those couple of seconds have killed what were decent crank seals.

I know very little about 2 strokes so maybe I've guessed wrong but I'm now super cautious of putting neat petrol into them. Keep us updated

 

[Pete.]

I'd not try to fire it up on neat petrol - I did that with a 50cc moped, it fired up fine, ran for 2 seconds on the fuel I'd suqirted into the carb mouth, then refused to fire again.
I'm sure those couple of seconds have killed what were decent crank seals.

I know very little about 2 strokes so maybe I've guessed wrong but I'm now super cautious of putting neat petrol into them. Keep us updated

More likely that the seal lips were stuck to the journals and the first firing ripped them up.

 

[angellonewolf]

I feel a bit more active today so went and had a look at the strimmer.

Looks almost brand new (as in no real use) but age problems -

View attachment 338703View attachment 338701View attachment 338702

Tank inside is pretty clean aside from bits of severed tube. Air filter spotless.

View attachment 338705

It is a b&q generic brand -

View attachment 338704

I strongly suspect the unit has had no more than a handful of runs from new. Compression is good.

I've not measured the tube yet, but, visually, it looks like about 3mm od and 1mm bore (smaller bore than I expected) and, curiously, even though it's all fallen apart, it's soft like silicone tube.

The priming bulb is stuffed.

I've not been on eBay yet but I assume generic priming bulbs will be common place. I guess I'll replace that and the tubing and see what happens then. It's all I can do at this stage, right? Or should I take the plug out and squirt some fuel in at this point?

Thanks to all for the comments.

When you say "inlet", speak to me like an idiot - are we talking under the air filter, or down the spark plug hole?

And, roughly what sort of quantity? I'm assuming straight petrol will be fine, not a mix (I won't bother with s mix if I can avoid it before I get the replacement parts)

Thank you.

Yep a small syringe full of neat fuel straight in the hole under the air filter where the air gets sucked in. Give e it a couple of pulls and it should fire up then die out.

as some above try fuel mix


oh andf if your putting fuel down the hole under the air filter pull the trigger/throttle to get the fuel in easyer

 

[roofman]

I started an experiment about 15 years ago with a Stihl leaf blower as a bet with my lads. We run out of 2 stroke oil on a job so i slackened off the vans sump nut enough to get a coke can half filled. Threw the old oil into 5L of petrol at 20/1 and proceeded to crack on. That same blower with the same piston kit and carb has ran on old used engine oil all its life and still has top compression and used daily, been running hotter plugs too to keep them clean. Ive also had my Stihl saws on the same brew for years with no ill effects and i know this for a fact as i rebuild all my own gear and see the normal internal wear on them. Strangers tend to give me a strange look when i am filling the machines up with black tinged petrol instead of the regular pink or green that 2 stroke oil gives

 

[Prajna]

I started an experiment about 15 years ago with a Stihl leaf blower as a bet with my lads. We run out of 2 stroke oil on a job so i slackened off the vans sump nut enough to get a coke can half filled. Threw the old oil into 5L of petrol at 20/1 and proceeded to crack on. That same blower with the same piston kit and carb has ran on old used engine oil all its life and still has top compression and used daily, been running hotter plugs too to keep them clean. Ive also had my Stihl saws on the same brew for years with no ill effects and i know this for a fact as i rebuild all my own gear and see the normal internal wear on them. Strangers tend to give me a strange look when i am filling the machines up with black tinged petrol instead of the regular pink or green that 2 stroke oil gives

Recently got a friend's 50cc Famel scooter running and had a scout round the net to find out the correct mix for it. Apparently it is happy with 25:1 if it's a mix with engine oil or 40:1 if it's modern 2 Stoke oil. But that's a Zundapp engine with a Bing 17mm carb, so a bit primitive. Your mileage may vary if you have a more recent carb.