Anyone here knowledgeable about 2 stroke engines on things like hedge
Thing is my Kawasaki hedge cutter stopped whilst ticking over and refused to
re-start. It had a spark, but seemed to be flooding, so I replaced the
diaphragms in the carburettor as this has cured the flooding problem in the
past. Now despite a new plug it refuses to start. Fuel seem ok, as the plug
now gets wet but not too wet. Spark is there. But no start? It has two
adjustment screws on the base of the carb (as well as the tickover screw)
any thoughts on a good starting position for these?
It isn't old fuel is it? If so, I would drain everything out and replace
with fresh petrol mix.
You need an aerosol of petrol + spark + vacuum at the right time..
No aerosol - No good. No petrol - No good. No spark - No good. No timing
- No good. Too slow a "pull" = no vacuum. So you need to check for each
(I have a starter motor with a rubber cone on the end that I use to
start such tools - I just can't pull hard enough. I've cut suitable
holes over the flywheel on my chain saw, hedge cutter, etc and just
push, press the power switch and even the most reluctant one leaps into
life. That solves the "vacuum" problem for me)
However, assuming that physical strength isn't your problem, spraying
Easy Start into the air intake is the next step. Some people use neat
petrol in a trigger-push aerosol bottle to do the same - but please,
nowhere near anything inflammable if you must.. If that works - then you
know it is carburettor problems.. If it doesn't, it's the electrics.
Assuming that machine has standard coil under the flywheel, then a spark
problem is going to be a dead capacitor or a tracking plug. Replacing
the plug is the easiest...
If all that lot is OK, then you are back into the carburettor. But I
suggest that you eliminate the rest and come back if needed..
Hi IIR most of these engines use a diaphragm carb' (Keihin or similar) they
have 2 running screws 1 for mixture & 1 for slow running start by screwing
both in fully then back off 2 - 2 1/2 turns as a start.
2 strokes can be a pain to start if not used for a while as they use the
crankcase to pressurise the fuel (separating the oil for lubrication)
[unless its a Suzuki which use a patented oil feed system ] .
A few tips to try :
Don't assume that if the plug sparks out of the cylinder it will inside some
times plugs fail under pressure.
Remove all fuel (disconnect the fuel line) remove the plug ,turn over engine
until no petrol or vapour is present, replace plug and turn over.
If the vapour is good fuel the remnants in the crankcase will allow the
engine to fire and may even run for a short time.
If the engine is dry add a drop of fuel (teaspoon full max) through the
spark plug hole and turn over slowly a few times refit plug and try to
If success tune carb' or look for fuel leaks.
If all this fails examine the crankcase for cracks or seal breaches.
Thanks Pal and "cj"
You have given me a lot to check.
How fresh is fresh when talking about petrol these days. The fuel I am using
was bought on the last weekend of May and is the last few litres from a 20
litre jerry can. It works fine in the 4 stroke machines but are 2 strokes
absolutely sure that it is ok. Whereas stored fuel could have
selectively lost some of the more volatile compounds, could have got
contaminated, etc. This could particularly be the situation using the
last few litres from a tank, where heavier contaminants may be more
likely to be present.
As to whether 4 stroke machines are more sensitive - its a bit academic
as individual engine designs are so varied. Some are designed to run off
almost anything liquid and inflammable. Some are far more demanding. I
can't pull start any of them :)
My strimmer still runs off a plastic can of 2 stroke I mixed 18 mths ago but
as Sue points out things settle and if left open to air the fuel can
evapourate in certain circumstances.
BTB Sue try a Sachs Dolmar Rotary if they still make them a 3 rotor 2 stroke
.no compression to mention swings easily starts first pull if tuned
correctly and goes like the preverbial S*&t of a shovel.
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