OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Victa Lawn Mower Frames Victa Vantage 2 throttle control issues

Hi Bruce,

I have a vantage 2 circa 1998. It become hard to control using the throttle control i.e. it only wanted to run flat out, idle or stop (no in between rev control). I suspected the carby, so I disassembled it and noticed that the large rubber diaphragm that the poppet valve is fastened to had partially flopped inside the chamber breaking the seal between the compartments. Also the grommet that holds the kill switch wire into the chamber is a bit distorted and maybe leaking air?

1) Do you think the problems could be related to the diaphragm seal? The diaphragm looks okay, and I have placed it back in its correct location and clipped on the cap that holds it tight.

2) Could an engine backfire cause the diaphragm to dislodge?

3) And should the distorted grommet for the kill switch make a good seal or is this distortion normal? It still seems to trigger the engine to cut out correctly.

Thanks in advance

James

James,

What I want to know is a detailed description on what you have done to the machine so I don't waste time with questions.

1. Did you do anything to the carby. :Wavey:

2. Did you remove the blade plate. :Tweetie:

Please give me step by step things that you have done to the machine as it will be quicker for me to give you a correct answer and even pictures will help as well.

Hi Bruce,

The mower is completely standard, never altered other than new blades. All I have done so far is:
1. Remove the plastic top cover of the mower (3 screws)
2. Remove the cutoff switch wires
3. Disconnect the throttle cable from carby.
4. Twist the carby off the coupling.
5. Dissasemble the carby following the G4 carby instructions found in your manuals section.
6. Report my findings/questions in my previous post.

Everything else is completely untouched



James

James,

1. Check the 'O'rings on the block(make sure they have no damage).

2.Check the cable is properly inserted into the cam.

3. Replace the grommet.

4. Did you take the starter off?

Hi Bruce,

O-ring is in good condition. I did not take the starter off (assuming you meant the starter cord assembly as my model does not have an easy start decompressor?).

Do you think the dislocated diaphragm could have caused the irradic throttle behaviour?



James

James,

I said 'O'Ring's. Please check the other one on the block(remove the two screws and slide off).

Yes the diaphragm will cause part of the problem. Make sure that you follow assemble directions as per manual.

Hi Bruce,

O-ring's both in good order. I have assembled the carby as per instructions and it seems to be back to normal.

BTW: It has always (since brand new) had a bit of a dead spot when working through the throttle range i.e. when the throttle is at the start position it idles, then if you push the throttle about another 1cm forward and leave it there, the revs die back and it will struggle and stop. If you avoid this point and push it just a fraction past this point it idles and as you move the throttle though to maximum the revs increase smoothly. It doesn't really bother me ... I am just interested to see if you have seen this before?

I have not changed the throttle cable/throttle lever in any way (except replacing the air filter cartridge).



James

James,

Does the machine blow much smoke in that position?

Have you checked the ring gap?

Does the carby have a white or black valve?

Hi Bruce,

No it doesn't blow much smoke at that position, it just seems to idle too low.

I have not checked the ring gap (head has never been off).

The valve is white ... I turned position 'C' on the valve to the jet as described in the instructions.



James

James,

Have you tried changing the springs on the diaphragm? :Wavey:

Hi Bruce,

No ... I did not realise the springs wore out ... okay will give that a go.

Thankyou for all your help.



James