A few months ago I purchased a new JCB-PCS38 chainsaw in anticipation of a
few trees that needed attention. I bought the JCB chainsaw because I
thought it would be good quality with good backup.

I started it for the first time two weekends ago and it ran perfectly, for
about 40 minutes. There was a tendency to stall if the throttle lever was
opened too quickly, and then, whilst ticking over nicely, it suddenly died
and wouldn't restart.

I've since discovered it will still start and run, but only on full
throttle. It will not run at low speed or tickover.

I suspect a fuel/carburettor problem, such as a blocked idle jet.

As it is still under guarantee, I spoke to JCB who agreed there may be
foreign matter in the carb. They seemed quite happy that I should have a
look myself, which I'm prepared to do. However, when I asked for a workshop
manual or exploded parts diagram, I was told there wasn't anything
available. It also seems that very few spares are available, just air
filters, chains and chainbars really.

I understand the carburettor is diecast aluminium rather than plastic like
some I've seen. Also, the jets are crimped in and not removable, so a good
blow-out with an airline seems appropriate. There are what appears to be
three adjustment screws on the left-hand side, visible through holes in the
yellow plastic casing. From memory, one is marked 'H' and another 'T'. I
couldn't find out what these screws adjust - does anyone know?

Does anyone have experience of these chainsaws? Are workshop manuals and/or
parts diagrams available? Are spares available - I imagine a new primer
bulb will be a common requirement?

The chainsaws are made in China and I guess to an extent they are just a JCB
colour coding and badging job. Are there other versions of this chainsaw
around, sold under some other companies name, with maybe better
documentation and spares backup?

Any help/advice appreciated.
--
Mike
-Please remove 'safetycatch' from email address before firing off your
reply-

On Mon, 18 Aug 2008 18:08:04 +0100, mlv wrote:

A few months ago I purchased a new JCB-PCS38 chainsaw in anticipation of
a few trees that needed attention. I bought the JCB chainsaw because I
thought it would be good quality with good backup.

I started it for the first time two weekends ago and it ran perfectly,
for about 40 minutes. There was a tendency to stall if the throttle
lever was opened too quickly, and then, whilst ticking over nicely, it
suddenly died and wouldn't restart.

I've since discovered it will still start and run, but only on full
throttle. It will not run at low speed or tickover.

I suspect a fuel/carburettor problem, such as a blocked idle jet.

As it is still under guarantee, I spoke to JCB who agreed there may be
foreign matter in the carb. They seemed quite happy that I should have
a look myself, which I'm prepared to do. However, when I asked for a
workshop manual or exploded parts diagram, I was told there wasn't
anything available. It also seems that very few spares are available,
just air filters, chains and chainbars really.

I understand the carburettor is diecast aluminium rather than plastic
like some I've seen. Also, the jets are crimped in and not removable,
so a good blow-out with an airline seems appropriate. There are what
appears to be three adjustment screws on the left-hand side, visible
through holes in the yellow plastic casing. From memory, one is marked
'H' and another 'T'. I couldn't find out what these screws adjust -
does anyone know?

Does anyone have experience of these chainsaws? Are workshop manuals
and/or parts diagrams available? Are spares available - I imagine a new
primer bulb will be a common requirement?

The chainsaws are made in China and I guess to an extent they are just a
JCB colour coding and badging job. Are there other versions of this
chainsaw around, sold under some other companies name, with maybe better
documentation and spares backup?

Any help/advice appreciated.

==================================
I don't know anything about your chainsaw but this place has an enquiry
facility and their service (for a few bits and pieces) was good:

http://www.espares.co.uk/?WT.mc_id=eml006

Cic.
--
===================================
Using Ubuntu Linux
Windows shown the door
===================================

'H' and another 'T'. I couldn't find out what these screws adjust -
does anyone know?

Any help/advice appreciated.

==================================

The H screw is to adjust the mixture at full throttle, the T would either
be to adjust the mixture at tickover ( I have normally seen them marked L
for low) or if attached to the throttle butterfly is for setting the
tickover speed.the other screw will be for whichever one T isn't.

Chris

On Mon, 18 Aug 2008 18:08:04 +0100, "mlv"
wrote:

A few months ago I purchased a new JCB-PCS38 chainsaw in anticipation of a
few trees that needed attention. I bought the JCB chainsaw because I
thought it would be good quality with good backup.

I started it for the first time two weekends ago and it ran perfectly, for
about 40 minutes. There was a tendency to stall if the throttle lever was
opened too quickly, and then, whilst ticking over nicely, it suddenly died
and wouldn't restart.

I've since discovered it will still start and run, but only on full
throttle. It will not run at low speed or tickover.


I would check out your oil/fuel mix first, as they are very prone to
incorrect mixtures.

dutchman wrote:
On Mon, 18 Aug 2008 18:08:04 +0100, "mlv"
wrote:

A few months ago I purchased a new JCB-PCS38 chainsaw in anticipation of a
few trees that needed attention. I bought the JCB chainsaw because I
thought it would be good quality with good backup.

I started it for the first time two weekends ago and it ran perfectly, for
about 40 minutes. There was a tendency to stall if the throttle lever was
opened too quickly, and then, whilst ticking over nicely, it suddenly died
and wouldn't restart.

I've since discovered it will still start and run, but only on full
throttle. It will not run at low speed or tickover.


I would check out your oil/fuel mix first, as they are very prone to
incorrect mixtures.



I had this happen on a stihl hedgetrimmer: turned out te clink was
blocked. Dismantled and blew backwards down the fuel tube and junk came
out. Reassembled and its fine..

overall your engine is running very lean..that's classic for 'stalls on
throttle open' and 'wont run at all'

Why it runs full throttle is a bit of a mystery, unless its a carb with
two jets and the low speed one is blocked.


Oh..another possible is an air leak somewhere around the throttle
area..that has less effect at full throttle. E.g. a carbuettor that was
half falling off might show this sort of behaviour. Or a cracked crankcase.

Has it been dropped?