What does this lock button do?

[the evil twin]

As said by others...

A 'traditional' choke only works on a carby petrol engine and "chokes" the air flow across a range of throttle openings enriching fuel/air mix. Ergo you cannot traditionally mechanical choke a fuel injected engine petrol or diesel.

A hand throttle does a different job as it adjusts the throttle input IE it's exactly the same as the foot throttle input and opens the throttle without changing or 'correcting' the engine fuel air ratio.

As per the manuals, it is a hand throttle or idle control for use as the operator see's fit. Largely disappeared these days but they were vital for any PTO application and still goddam handy for low range or rough terrain work.

There has been probably 100's of fatalities over the years because of hand throttles. Mainly farm related accidents were someone goes under the vehicle or tractor while feeding the stock or whatever after setting the throttle and jumping out of the seat to scatter feed from a tray or trailer.

[gec]

Also if ya want anymore proof, put ya foot on the accelerator pedal when ya pull the hand throttle knob and you will feel the pedal move, infact pushing the pedal down makes it easier to pull out the hand throttle.

[Mark_C]

Thats ticked one of my boxes, as i inherited the vehicle from my Dads estate i don't have an original manual and i wasn't too sure what it would do to the choke. Thanks for the heads up.
Mark

[mick64au]

Nice to see I am not the only Gumby - I thought it was a choke as well - but the lock part threw me. Winter coming so no doubt it will be getting used soon.

[bordertech]

oh yeah that would make a lot of sense. Has anyone seen this symbol on anything else? like maybe hydaulics?

If it's a diesel it's a fast idle only, if it's a petrol it's choke to reduce the amount of air into the engine to make it run richer whilst increasing the idle at the same time for cold starts. So on a petrol it's a fast idle as well as a fuel-air mixture control. Diesels dont do or need this enrichment control. They have glow plugs instead to warm up the combustion chamber until a predetermined temperature is reached then they turn off. If the engine is already hot they may only stay on for a second or two.
Cheers, Dave

[taslucas]

This thread has figured out that the knob in the petrols is not a choke. It is a hand throttle only.

tappa slappn about

[L--RYDA]

Interesting thread ...Anyone had an issue of a stuck throttle control switch ? The one in question had been operating freely and turning anti clockwise / clockwise without any problem , now it seems as though it has been over-cranked and will not turn freely , its very tight and will not hold in place , it half turns back upon moving now, and feels as if its under pressure ? Any ideas for an easy fix , cheers?!

[doka404]

Its definitely a hand throttle.
From memory (an old mechanic explained it to me one day) the symbol is just a "universal" image represents the butterfly in a throttle body/carby. so it can be used for a number of things..ie hand throttle.

So if you see it on say a chainsaw which has a lever for a choke you will see two pictures like this.



On the GQ's its common for that knob to break off by pulling on it and locking it (ie using it) so best thing is to gently press the pedal to where you want it, then you will see that the knob slides out easy and can be locked off. If you pull the knob out by itself it will move the accelerator pedal as well..or at least has on all my GQ's

[L--RYDA]

Thanks doka404 , just not sure about pulling the knob towards me , its seems that it can only turn clockwise/anti , and seems as though the scans on previous page only mention turning the knob not pulling it , cheers . I will try your suggestion though .

[MrSir]

Turning clockwise/anticlockwise was just a revised method of operating the control. Older GQ's had the pull/twist lock type, later patrols had the turn style. They changed from pull/lock to turn style to address the issue mentioned above, snapping. Only trouble I've had with the turn type in mine is it takes too bloody long to adjust when your bouncing about in the rough stuff.