OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Victa Craftsman 2 Stroke

Hi All

Ok so I have found myself a new project - 1 Victa Craftsman 2-Stroke with Power Torque Engine.

Having rescued this from the hard rubbish , and identifying that one of the blades had a crack running 3/4 the way through , I was curious to see if it would start.

A splash of petrol with a cap full of oil and several hard yanks on the pull start and I was ready to give up... and then with a cough and splutter everything comes to life.

It runs and it cuts - even with it's cracked blade... So, looking more closely I discovered:

1. that a hose from the decompression chamber/valve (? UFO shaped thing bolted to the cylinder head) was not connected at other end - where does this go? All I know is that it clips onto something that seems to be made of plastic (yes it is still in the disconnected end...)

2. that the compression seems low (I checked by feeling for resistance while rotating the cutting deck) - although I don't really know the 1st thing about 2 strokes so thought that compression might be low anyway given overlap b/n inlet and exhaust??

3. spark plug was oily black

4. when I put my hand in front of the spark plug and around the cylinder head (trying to feel for gas leak) I could feel a lot of air rushing past - I think this is normal (there seems to be a fan with deflector from the cutting deck)

5. there is no play when I try to move the cutting deck (in/out or sideways)

This mower has been neglected and cleaning it was like removing compost from a garden. It has come up looking quite good and I'm thinking it is a keeper.

Basically I'm looking for advice on how (or more where) to reconnect the decompression thing and how to check the cylinder compression properly...

Cheers

Steve

The hose from the decompressor fits onto a stub behind the carby near the inlet manifold.

The reason you cant feel much compression is because of the decompressor.

Dont worry too much about the plug, give it a really good run then check it again

Hello Steve

The decompressor hose connects to the carby, on the manifold side of the carby, you will need to take the carby off the motor to see where.

The decompressor will not be working correctly without this connected thats why it will seem like it is low on compression.

To check for compression, pull the decompressor out of the head and fill the hole with an old spark plug then try and turn the motor over.


Thanks

Martin

Thanks Martin & Joe

The stub had broken off at the carbie - knowing where to look made finding the left over hole much easier to find. I mucked around with it for a few hours this morning and after pulling the carbie 1/2 apart (until I stopped finding dust and dirt) and gave everything a good clean.

Did not have a spare spark plug so sucked on the de-compressor while rotating the cutting deck by hand. I was quite contorted; surprised GF did not take a picture!!

Anyway, contortions aside this resulted in a definite improvement in compression; so de-compressor seems to work...

Drilled out the hole where the stub was and stuffed some irrigation tube in so that I could hook up the de-compressor again (see pic). Unfortunately I managed to crack the carbie housing near the connection point - I think crack is cosmetic only, annoying.

Once reassembled the mower started 2nd pull . Very happy considering the carbie was emptied.

However connecting / disconnecting the de-compressor did not seem to make any difference to the running of the engine, and it sounds like a tractor.

With engine running I sucked on the the de-compressor and still no change...

How does the de-compressor work? Is it:
pulsing open and closed, or
constantly closed when the engine is running?

Many thanks, S



[u][/u]

The decompressor is capable of closing itself just from the air pressure from the compression blowing past it, once it is shut it usually seals well enough without the vacuum to keep the engine running, the vacuum hose just helps to make sure it is staying closed.

Ok - So I'm thinking option 2; de-compressor stays closed when engine is running.

Will it hurt the engine to run with it plugged?? [Edit: what does the de-compressor do?]Just make it easier to start??

Yep the decompressor stays shut, wont hurt the engine as such, at the worst it will make the starter rope wear a little quicker.

Kewl :-)

Well now the rain has come there is no more fixing to be done today.

Looks like a new air filter and set of blades will be about all that this mower needs.

BTW - To anyone with a similar carbie problem (broken vac stub) I don't recommend drilling out your carbie (see pic above). The tube that I put in has to be cut flush to the carbie and the hole overlapped the main o-ring used to seal the carbie. I ended up plugging the hole that I made with some Aluminium tape and will probably look at either a new de-compresser or running a plug :-)

BTW - thanks for your help Joe & Martin

No probs Steve, look like Jow beat to the post ahahhahahaha, we must have been typing at the same time.