OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Two Stroke Lawn Mower Frames Automatic Throttle Control ????

Hi , Everybody ,
I'm a virgin so please be gentle with me ..
I'm an old aged Pension , so the $$'s are few and far between.and can't afford to pay for repairs .

I have a Victa, Mustang Self propelled 20" with a High Performance Straight induction. and Ramflow Engine Pak. . It is about 20 yr old.

I haven't used the Mower for quite a while , after cleaning out old Petrol (that wouldn't work ) replaced the Drive belt with car fan belt. .... the Mower now starts easy and runs good.
I think it use to have Auto Throttle Control ???, so when it hit the Longer Grass it would Rev more and Rev less when no load.
Now it is only Revving when you use Accelerator , and then it Revs too hard when in short grass, and drives too fast too.

I was wondering if there was anybody coud tell me if it did have Auto Throttle,
How does it work ?? and what the usual fix is ??

It would be much appreciated .

Thanks Ron

Ron,

We need to know what type of carby you have on your machine.

1. Is it a G2 Type carby?

2. Is it a G3 type carby?

3. Is it a G4 type carby?

It maybe a G3 type. If it is less than 20 years old it could be a G4 type.

Anyway let us know so that we can give you the correct information on how to correct your problem.

Hi Bruce ,
Thank you for your quick reply,....... I wouldn't know how to tell model of Carby, but I can tell you a bit about it if I can remember .

1. It is Black Plastic with 4 Round intake/exits
2. The overall shape is that of a Cylindrical Cross
3 Looking at it from the Left side of the Mower it has a White Plastic Disc,phillips screw in middle, with Intake spout ,Rubber and primer bulb. Inside that is white Float needle and seat.
4. On the opp side of carby is Air intake with Throttle Cable inside ,Cutout wiring exit spout . I think there is a spout that
a tube to the Crankcase fits on.
5.To the left is where the Carby Pushes + Twists onto the
Engine,.. inside there is the white Plastic Control Valve

6. To the Right is a Plastic Cap that clips onto the Carby it has a Vacuum ??? hose via a spout connected to it . under the Cap is a Spring . Metal plate (that the spindle to the C/Valve goes thru) , a Diaphram Rubber. and a Cam that the Cable clips into to regulate the Air intake. and maybe another fine spring .

Maybe if I know what to look for to tell the Different from each other. I got the Mower about 20 year ago .

Something else that might help is the Black Rectangular Petrol Tank sits over the Carby, on a metal Angled Plate that is held onto the mower by 2 Nuts + bolts that are accessed by lifting up the rear flap that covers the Grass shute.

Regards ..Ron
PS; if I had a picture to Identify it , might help ........... here's my Email... ronsmall@tpg.com.au Cheers.

RonS,

Your carby is a G4 type and we have all the information under parts list and manuals area.

Its a full crank 160cc (not powertorque) with G4 carburettor going by the description, I think Bruce

edit: beat me too it !

Hi, Bruce,MST,
Thanks for help, ....
On top of the engine plastic recoil cover is a Red Sticker with the engine type I mentioned earlier, and Something I forgot was V50 is on it too.
I just had another look at the carby, and on the the large black round cap that clips on the End it has a spout on it that has a hose that lead to Crankcase, under that cap is a Spring then Metal plate with a Spindle clipped onto it and under that the Diaphram Rubber,........ On the Round Plastic Cap is a part No CR3636A.
The pipe (hose)that comes off the Lower part of the Carby on the other side comes back over the top to a Round Housing (with maybe a Diaphram/ Valve inside ) that is screwed onto the Head ( Is that a Zip Start valve )

What I would like to know is,..... does this mower have the Auto throttle.....IE: when it is under load it increases and when it's not it decreases ?? ( I can't remember, haven't used it for ages ) if it does,... it doesn't work now , just by manual throttle .
If so what could cause the Auto part of it not to work. and what are the principals that make it work. ?
And the Manual you mention Bruce, what does that include, troubleshooting or just parts ID . and numbers , as I said before $$ are limited.

Regards ..Ron

Ron,

It is a workshop manual and has detailed information as well as trouble shooting.

The tube that goes from the carby to the motor is the one that governs the engine. If you have a blockage where it pushes onto the motor it will not work and if the diaphragm under the cap is not sealing properly, that could cause problems as well.

I hope that this is of some help.

Hi Bruce ,
So the engine is suppose to change speed according to the Grass height ...correct ?

Regarding the Manual, ...does it cover the Complete Mower,
Eg: Rear drive Diff, and Belt , Manual and Auto Throttle controls , and Start recoil etc.

And Do I have to know the Exact mower model ??.

How long do I have access to the manuals ??
and what is the Cost ?
Cheers ...Ron

Ron,

All the engine areas are covered and as to the rear drive that can be uploaded as well.

Hi Bruce,

Do I have to know the Exact mower model ??.
So the engine is suppose to change speed according to the Grass height ...correct ?

How long do I have access to the manuals ??
and what is the Cost ?

Cheers ...Ron

Ron,

You do not have to know the exact model.

Yes the speed should change.

Access has no time limit at this stage and the donation amount is set at $10 unless you think that is worth more.

Thanks Bruce,

What the mower does now , is I set the Rev Speed, get pulled along at a Nice speed in the Shorter grass , I hit the longer Grass it nearly dies , I move the throttle to faster , it goes good , then if I hit the Shorter grass again , I'm running at 25mph behind the Mower and the engine is revving it's head off .
After your reply, mentioning the Tube to the Motor , I sussed out the Tube and the Spout on the Engine .
The tube wasn't a tight fit on the spout, and the Spout may had some crap in it. I hope it did !

I will wait for this "wonderful" Rain to stop before I try it . it is a pity that all this rain we have lately most ends up in the Sea.
I think we need more politicians like "Curtan"....
( who started the Snowy Mtns Scheme and wasn't worried about the fact that it wouldn't be finished for 20 yrs when he wasn't in office)

All the Best ..........
Thanks for your help,... I'll let you know the outcome
Ron.