Any two-stoke experts able to give help.

[sally wright]

Dear Richard,
what you have to realise is that most of the companies producing these machines operate in continental climate zones. These get bleeping hot and cold and the maintenance rules are different to the ones for our generally tepid and damp climate. It is about moisture, air and the oil interacting to produce the goo which blocks things. The salad dressing effect I call it.
Draining is good and should be done for 4 stroke machines but even then it is not recommended for those with steel tanks as it can allow the formation of rust particles which can really do nasty things to an engines innards.
Last week I took our old Allen hovver (aged about 15) off the wall where it has hung since October and filled it with 2 stroke mix and it started second pull. I cannot recall the last time it had anything mechanical done to it bar a sharpen and dust. It gets around 20-25 hours work a year so it sits around a lot.
I am sorry I missed giving a better answer last week but I was distracted by the winter vomiting bug.
Regards Sally Wright.

[Ricard with an H]

but I was distracted by the winter vomiting bug.
Regards Sally Wright.

I was doing that a few weeks back, took me ten days to get over it and I lost a few pounds.

What you say makes perfect sense Sally, i'm not letting my machines dry-out over winter again. The fact I had three machines all with the same symptoms, none of those machines had any mechanical or physical fault then once started did half a days work flawlessly.

I finally stripped the 48 down after it started second-pull on this mornings cold, damp and wet day, then I remembered I hadn't checked that the circlips were seated into the grooves either side of the gudgeon pin on the 23. Good-job I remembered, one wasn't seated. If they come out of the groove they can damage the cylinder and piston.

Alls-well that ends well though I still think two-strokes are a bit of a black-art, our local experts who have many years experience just fiddle and try different changes until things work. No instant diagnosis, you pay them to fiddle though they do have a lots of spares to hand. Today I saw a 30 years old machine that hasn't worked for ten years cough into life, two young blokes aged 75 and 50 (Father and son) behaving just like a baby had been born. I think it was an old Toro side-eject.

[Clive.]

Middle of the night pondering...lead me to remember to add that 2 strokes on small garden machinery and chainsaws often require a no load top speed setting with a specific tool/blade fitted. Adjustment made via the H High speed mixture screw to achieve a manufacturers recommended speed. This will often see the engine note just warbling rather than running clean...such that it then comes in virtually clean note when work is applied. This certainly applies to most 1980s/90s machines.
If they are tuned to run cleaner/faster off load it will cause inability to sustain load and cause overheating...and is very likely to cause terminal engine damage.
Too slow, rich, will also impact on work ability and the engine and exhaust will oil and coke up.

The rev counter used is a hand held device that monitors spark. A more simple device is a frequency measuring sirometer with a vibrating wire often easier to use on slower running mowers.

Slower 2 stroke engines on most post 1960s mowers will have engine speed governing whilst on a brushcutter/chainsaws etc the no load speed is the restricting/governing.

More recent low cost 2 stroke machines may well now have a fixed, non adjustable, main jet, have no H screw and may thus be more fussy with regard engine faults and air filter. Recent higher spec machines may have a compensating mechanism within the carburettor that keeps the mixture/speed good through the service interval of air filter.

Our large brushcutter at work, a 1995 model at the base end of clearing saws, has a specific tuning requirement to achieve a no load top engine speed and then a final quarter turn richer to allow the overspeed regulation to operate correctly.


I perhaps should be dreaming of other than tuning brushcutters. but seeing as I remembered it I thought I would post on.

Clive.

[Clive.]

...and that bug.....had a dose of that in 2009...not good at all. Brought to a working holiday I attended and by the end of the week we all had it.!

I just made it home and then was off work for a week..usually unheard of..and was actually quite frightened that something was really seriously adrift... until I learnt that everyone on the holiday had taken it home.
I could only just about sip water for the whole of the week....then I passed it on to the family........



Clive.

[richard p]

the draining fuel question has been arround for years... its been argued on here before... some swear by draining others leave their tanks full.

personally my two and four strokes get left with whatevers in their tanks, ive never drained out old fuel but do usually top up with fresh before starting first time in the spring.

ive got a honda engined mower that cuts out randomly...local dealer reckons its dirt in the fuel system but was too busy to do any more than blow air up the float chamber as a temp fix, its been at the back of the shed for at least a year along with another one with a rusted out deck , last week i took the "good" engine off the rusted deck and fitted it to the good deck, its been sat for at least a year with a splash of fuel in the bottom of the tank... i poured in about half a tank of fresh petrol and it started on the first pull.

[Clive.]

...Random carb effects on Hondas has jogged my memory cogs.... Many moons ago we used to come across carbs on Honda mowers where the main jet came slightly unscrewed in use and thus the separate brass emulsion? tube above it used to move up and down. This main jet is set vertically in the carb central passage above where the carb bowl retaining bolt is. This would relate to 20+ years machines..not sure on more recent.

In the back of my shed is a Honda 21-5 that was put in there 25 years ago. ..one day I dreamt of an engine swop....I acquired an engine 20 years ago....oh well, one day. ..it might just be dry of fuel..

Clive.

[Ricard with an H]

It's good when you find a solution to the problem. It's very irritating when you have a problem that doesn't have a solution or an obvious area to investigate.

Yesterday evening I pull my smallest machine of it's hanger for a trimming session, it started first pull. After the trimming session I noticed the tank was empty and unsurprising the machine stopped.

I topped the machine up and had a cuppa-break, but the machine refused to start. This machine has just previously started and worked flawlessly, when it stopped it was more like the cut-off switch had been deployed than a fuel shortage which is usually not an instant stop. This machine already has a new plug and if I check the coil later today I doubt I will find a fault even though I hope I will.

It's good to share.

[peter]

I've had that with 4-stroke Briggs & Stratton, I think it's a heat issue where the fuel vapourises en route from tank to engine.

At any rate if I left it for a while after refuelling the problem would go away.

[Ricard with an H]

At any rate if I left it for a while after refuelling the problem would go away.

My machine started first pull this morning and just done 30 minutes work, I had to stop for a re-fuel and didn't want the same to happen as what happened yesterday but thats daft.

If it's the great-gardener who cares for us all having a little fun can I suggest you've had your fun and would you mind moving-on.

[robo]

with my rotavator lying sick on our allotment I borrowed one from a friend with the promise from him "if you can get it started" you can use it, its only 2 years old a thing called an eckman, when you take the spark plug out and pull the start cord you get neat petrol shooting out of the plug hole, no problem I thought strip and clean the carb should be up and running in no time, what a joke, I thought the needle valve would be partly blocked causing it to flood problem is no needle valve, I googled eckman made 3 phone calls to them none answered sent emails no replies I wanted to ask the availability of a new carb but getting nowhere

[Ricard with an H]

Hi Robo.

From my limited experience it appears that quite a number of machine manufacturers use just a few carb types and there are quite a few pattern-types available though you have to identify them by the graphics or photo on-line. Having said that I still haven't found a suitable supply of spares for the three types of carb I have on my five machines.

I can get a non original carb, but no spares. I am trying to avoid the hike in price that comes from ordering a non stock item with the handle 'Kawasaki' on it.

For example. Two types of Walbro appear regularly on most small machines up to 50 cc.

let us know how you get on.

[FelixLeiter]

I topped the machine up and had a cuppa-break, but the machine refused to start.

I think the "cuppa break" is key here. I find that with most small engines, they either start easily from cold with choke, or easily from hot when they have been doing work without choke, but in between the two (luke warm, if you like), they can be a swine to get going again, even with half-choke. I have a chain saw and a strimmer, both Stihl, which behave like this. My only recourse is to leave them for at least two hours then start them again with full choke, from cold. And of course, after the fuel's run out, there's often an air lock to contend with, and that can take many pulls to draw through.

[Ricard with an H]

Made me smile Felix, you just confirmed my theory about two-strokes starting and running being a 'Black-art'.

Yes, you're absolutely right. It's starting from cold and starts from hot, it even starts from cold when there isn't fuel in the tank so it's starting on the remains in the carb and a little vapour.

I'm glad you mentioned Stihl because we're talking about high-end machines and whilst some prefer one brand to other, along with Husqvarna, these are all high-end machines.

My Husqvarna chain saw is no more or less quality engineering than either of the other two other than it has a de-compression valve for starting which is a massive help. My 48 cc Kawasaki brush-cutter doesn't have this de-compression valve so on that score alone I would always look at Husqvarna first if I ever needed to buy.

[richard p]

i do a lot of strimming with a clients echo strimmer....over the years ive learnt to kill the ignition as soon as it stutters on low fuel, if its left to run out completely its a bxxxxxd to get to run again, kill it as soon as it stutters , refill and repeatedly press the priming bulb till its got fuel in it and it restarts on first pull.

took my reengined honda mower out this morning, started first pull....soon started to run a bit rough, then died, air turned a bit blue.

then i remembered the petrol tap....started first pull.

[Ricard with an H]

Thanks Richard, you've raised another point. If you're working on a bank you'll often get fuel shortage symptoms because of the angle of the tank or the pick-up filter hasn't dropped to the bottom as in the case of some lightweight fuel filters that are so light they almost float.

Most of my machines have a steel-bodied filter with a fabric-wrap, because of the steel body I figure these are less likely to migrate into a high position.

Yes/no ?

Like I keep reminding you-all, i'm just learning.