Tried sorting out a neighbour's old McCullock mower today and didn't get
very far.
Symptoms:
1) 'hunting' all the while
2) won't restart when hot (so tape round the throttle; cap off plug to stop!
3) starter cord has no effect when the engine is hot

so far:
for 3) I can't see any cause - looked under the cowl and a gentle pull on
the cord extends the pawls and they seem free.

for 2) I've had to remove the tape so have suggested a sliding clip/band.
This problem might be related to the hunting.

for 1) I wondered if it might be lack of fuel, as t'other neighbour managed
to get my Honda mower hunting by forgetting to turn on the fuel.
Fuel's getting through, float chamber almost clean and the jet's had a
blow-job from a foot-pump.
Looked at the plug: grey on the electrodes and black elsewhere.
End of exhaust black, so cleaned adecade's-worth of crud from the air
filter.

Still hunting, dammit!

Found that the throttle doesn't have any effect except run and stop and also
doesn't directly move the levers on/near the carb. It moves a plate against
a spring on the opposite side of the engine.
When the engine is hunting, a c. 2mm move of the little lever on the carb
gives full revs and no hunting.
What I don't know is the method of controlling the revs - as the engine
hunts the lever on the carb is moving in time to the hunting.

Any pointers please to how this works and how to correct the fault?
--
Peter.
The gods will stay away
whilst religions hold sway

On 07/09/2012 21:49, PeterC wrote:
Tried sorting out a neighbour's old McCullock mower today and didn't get
very far.
Symptoms:
1) 'hunting' all the while
2) won't restart when hot (so tape round the throttle; cap off plug to stop!
3) starter cord has no effect when the engine is hot

so far:
for 3) I can't see any cause - looked under the cowl and a gentle pull on
the cord extends the pawls and they seem free.

for 2) I've had to remove the tape so have suggested a sliding clip/band.
This problem might be related to the hunting.

for 1) I wondered if it might be lack of fuel, as t'other neighbour managed
to get my Honda mower hunting by forgetting to turn on the fuel.
Fuel's getting through, float chamber almost clean and the jet's had a
blow-job from a foot-pump.
Looked at the plug: grey on the electrodes and black elsewhere.
End of exhaust black, so cleaned adecade's-worth of crud from the air
filter.

Still hunting, dammit!

Found that the throttle doesn't have any effect except run and stop and also
doesn't directly move the levers on/near the carb. It moves a plate against
a spring on the opposite side of the engine.
When the engine is hunting, a c. 2mm move of the little lever on the carb
gives full revs and no hunting.
What I don't know is the method of controlling the revs - as the engine
hunts the lever on the carb is moving in time to the hunting.

Any pointers please to how this works and how to correct the fault?


Change the carb diaphragm - about £3.50 (Amazon) - and clean the air filter

On Fri, 07 Sep 2012 22:12:30 +0100, Nospam wrote:

Found that the throttle doesn't have any effect except run and stop
and also doesn't directly move the levers on/near the carb. It moves a
plate against a spring on the opposite side of the engine.
When the engine is hunting, a c. 2mm move of the little lever on the
carb gives full revs and no hunting. What I don't know is the method
of controlling the revs - as the engine hunts the lever on the carb is
moving in time to the hunting.

The engine speedis normally controlled by a vane in the draft from the
fan near the recoil starter. Engine slows draft drops, vane moves, opens
throttle, draft increases etc. Thesprings and linkages associated with
this are uselly very sloppy and not easy to really follow what is going
on with engine stopped. It might just be a spring in the wrong
place/broken or similar for a linkage including bent.

Change the carb diaphragm - about £3.50 (Amazon) - and clean the air
filter

That is another possibilty our mower got one of the little flap valves
stuck open and that made the engine hunt. Found it when I carefully took
the carb off the tank, put back ensuring flap valves in right place and
decent overlaps etc. That was a number of years ago now...

A McCullock (McCulloch?) probably has a Briggs & Stratton engine their
website is pretty good with full manauls etc. Bu may not cover the
throttle linkages as that is really part of the mower not the engine. Try
the McCulloch site?

--
Cheers
Dave.

On Fri, 07 Sep 2012 22:39:02 +0100 (BST)
"Dave Liquorice" wrote:

On Fri, 07 Sep 2012 22:12:30 +0100, Nospam wrote:

Found that the throttle doesn't have any effect except run and
stop and also doesn't directly move the levers on/near the carb.
It moves a plate against a spring on the opposite side of the
engine. When the engine is hunting, a c. 2mm move of the little
lever on the carb gives full revs and no hunting. What I don't
know is the method of controlling the revs - as the engine hunts
the lever on the carb is moving in time to the hunting.

The engine speedis normally controlled by a vane in the draft from
the fan near the recoil starter. Engine slows draft drops, vane
moves, opens throttle, draft increases etc. Thesprings and linkages
associated with this are uselly very sloppy and not easy to really
follow what is going on with engine stopped. It might just be a
spring in the wrong place/broken or similar for a linkage including
bent.

Change the carb diaphragm - about £3.50 (Amazon) - and clean the
air filter

That is another possibilty our mower got one of the little flap
valves stuck open and that made the engine hunt. Found it when I
carefully took the carb off the tank, put back ensuring flap valves
in right place and decent overlaps etc. That was a number of years
ago now...

A McCullock (McCulloch?) probably has a Briggs & Stratton engine
their website is pretty good with full manauls etc. Bu may not cover
the throttle linkages as that is really part of the mower not the
engine. Try the McCulloch site?


B&S are very helpful, they sent me by return the manual and parts list
for an old engine on a Hayter that was not listed on their website for
download. It had very useful info on carb. settings etc.
--
Davey.

On Sep 7, 9:49*pm, PeterC wrote:
Tried sorting out a neighbour's old McCullock mower today and didn't get
very far.
Symptoms:
1) 'hunting' all the while
2) won't restart when hot (so tape round the throttle; cap off plug to stop!
3) starter cord has no effect when the engine is hot

so far:
for 3) I can't see any cause - looked under the cowl and a gentle pull on
the cord extends the pawls and they seem free.

for 2) I've had to remove the tape so have suggested a sliding clip/band.
This problem might be related to the hunting.

for 1) I wondered if it might be lack of fuel, as t'other neighbour managed
to get my Honda mower hunting by forgetting to turn on the fuel.
Fuel's getting through, float chamber almost clean and the jet's had a
blow-job from a foot-pump.
Looked at the plug: grey on the electrodes and black elsewhere.
End of exhaust black, so cleaned adecade's-worth of crud from the air
filter.

Still hunting, dammit!

Found that the throttle doesn't have any effect except run and stop and also
doesn't directly move the levers on/near the carb. It moves a plate against
a spring on the opposite side of the engine.
When the engine is hunting, a c. 2mm move of the little lever on the carb
gives full revs and no hunting.
What I don't know is the method of controlling the revs - as the engine
hunts the lever on the carb is moving in time to the hunting.

Any pointers please to how this works and how to correct the fault?
--
Peter.
The gods will stay away
whilst religions hold sway


Some mowers have an air governor to regulate the speed. A flap in the
cooling air stream that controls the carb. This could be sticking/need
a drop of oil.
Otherwise hunting usually caused by running lean. Check air vent on
fuel cap.
Check fuel filter (may be inside fuel tank).
Check fuel for contamination/water.

On Fri, 7 Sep 2012 23:47:43 -0700 (PDT), harry wrote:

Any pointers please to how this works and how to correct the fault?


Some mowers have an air governor to regulate the speed. A flap in the
cooling air stream that controls the carb. This could be sticking/need
a drop of oil.
Otherwise hunting usually caused by running lean. Check air vent on
fuel cap.
Check fuel filter (may be inside fuel tank).
Check fuel for contamination/water.

Thanks for all of the suggestions. The other sources of information and
spares I'll follow up.
I'll also check all the other things above and in other posts.
--
Peter.
The gods will stay away
whilst religions hold sway

On Fri, 7 Sep 2012 21:49:32 +0100, PeterC wrote:

Tried sorting out a neighbour's old McCullock mower today and didn't get
very far.
Symptoms:
1) 'hunting' all the while
2) won't restart when hot (so tape round the throttle; cap off plug to stop!
3) starter cord has no effect when the engine is hot

Eventually found out that the engine isn't B&S but Tecumseh! (does help to
know this bit!). From a forum discovered during a search, came across a
recommendation for http://www.uni-power.co.uk/ . e-mailed a request for help
and have had an exchange lasting for a couple of weeks now, eventually
leading to some rather 'bulky' manuals being e-mailed to me.
I still have to get to grips with the info and then find a source of
TecumsehTuits, but I must say that the help from this company and the
correspondent has been v. good. Only connection is asking for help - heven't
even bought anything.
--
Peter.
The gods will stay away
whilst religions hold sway