OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Starter pulls ok when no spark plug installed

Yep, clean it up like you are a surgeon, lay it out in sequence mate, so you get it back together in the right order.

Point to note: keep control of that small spring, if it springs off onto the floor it can be very hard to find, even with a magnet, just ask me.

Hi again Mark, gave the decompressor a quick clean, put it back on, same result ie starter jerks. When the decompressor was off and the hole uncovered, the starter did not jerk.

I tried putting a spark plug into the decompressor hole and blocked off the hose that was connected to it with some cleaning towel, the starter jerked again and mower did not start. The muffler is a little rusty around the mouth but is up against the engine. Is there anything else I can try, the piston and engine bore are smooth and in otherwise good condition.

tiger,

So with decompressor removed and and a spark plug inserted into the decompressor valves port.
You still have a jerky pull on the start rope.

What you are feeling now, is the normal compression of the engine.

Remember the valve is there for an effortless start.

When stripping and cleaning the decompressor, make sure the diaphragm is sealing against the metal plates that sandwich it, the plates mating surfaces need to be smooth and clean.

Mark, with the decompressor removed and spark plug inserted I see no difference to when the decompressor was inserted, I'll keep trying but this is getting frustrating.

Alright, so no difference.
I am afraid that things dont aways go your way when fault finding mowers.

From this distance I cant feel this jerking action of the pull starter.

Let me tell you that with a spark plug blocking the decompressors port there should be quite a lot of resistance when pulling the starter cord and it will be jerky when pulled slowly.

Now with a seviceable decompessor in, it should be easy to pull the starter cord.

tiger, have you tested the valve closes under suction?

I couldn't take the decompressor apart but cleaned what I could with the air compressor, if I blow on the decompressor nozzle the valve is activated so it seems to be working. If the decompressor is not on the mower it pulls easily, as soon as that port is closed, the pull starter is hard to pull.

Just about ready to pull this apart for spare parts, if anyone in Melbourne reckons they can fix it, it's yours.

Mark could you elaborate on what you mean by closing under suction?

Tiger, if it has two sharp compressions per revolution, and if they are the same whether the decompressor is fitted or is replaced with a second spark plug, the decompressor valve is not working. That could be because the valve is defective, or because the correct signal is not reaching its activation port. The engine should start and run perfectly with the decompressor not working, it will just be hard on your arm, and on the starter mechanism.

I can't pull the starter cord more than about 6 to 8 inches no matter whether the decompressor or spark plug is in. Are there any other explanations or things i can rule out?

Tiger, if you where located in Brisbane I would invite you round and we could both fix your mower and have a yarn.

Place a piece of pipe on the valve as below.

Then suck on the hose, the valve should close, see closed valve below.

I use a clean pipe for this, I dont put petrol in my mouth.

I certainly wouldnt tell you how to feel or act, but I try not to let a mower defeat me, it is just a hunk of metal.
When I hit a dead end, I put it aside and come back to it later.

Thanks Mark and I would definitely take you up on your offer, who knows might even drive up to Brisbane but don't think the car would make it.

Appreciate your support but I've spent a few hours on this machine and feel I haven't got anywhere. Your photos are great and really make the forum a superb resource for many people.

If the decompressor is really to blame here I know someone who has a later Victa but I think there decompressor is sealed, wonder if they're interchangeable? Could try and put there's on mine.

hello again tiger,
Just read your 2nd last post, you say the cord will only pull 6 to 8 inchs out of the starter.
There is something else going on here then.

Starter cord should pull out to around 1000 mm.

I am not sure, I will have to think about that.
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The valve off a later victa may be different, there are different lengths.

Can you check the wire part on your pull starter.
When you pull the cord, does the wire come out into the groove as per the image below?


Upper wire should be in the groove / Lower wire underneath.

Friction spring is as per your photo, maybe there's some type of compression lock.

G'day again tiger, a question: is the blade plate on & done up tight?
I know this was mentioned earlier by other forum members, but just checking.
The engine relies on the inertia from the blade plate to turn over correctly.

Hi Mark, the blade plate has been taken off because the nut did not do up tightly. When the blade plate was on it behaved the same way.

Tiger,

If you don't put the blade plate on correctly we will just go around in circles and you will never solve the problem.

Tiger, turning over that engine without a working decompressor will call for a fairly serious effort, and a properly coupled blade plate. Otherwise, unless you are meatier than average in the arms, it will just stop when you get to the first cylinder compression, and you will think there is something wrong with the engine, when there isn't. The decompressor is there for a reason: without it, the engine is much too difficult to turn over. Since your decompressor is not working, and your blade plate is not there to give you a reasonable amount of rotational momentum, it would take an accomplished body-builder to turn the thing over. Just pray it doesn't fire, because with no blade plate, it might break a couple of your fingers on the starter handle when it inevitably kicks back.

I'll put it on as best I can but the thread is rusted so not sure I can do it up tight.

Wire-brush the thread first, then check that it will screw right down to the end of the crankshaft without the blade plate fitted. Then you can be sure it will pinch the blade plate when you reassemble it with the blade plate in place. Finally, ensure the screw is tight - you don't want broken fingers.

I have attached the blade holder and it is a little easier to pull the cord but still jerks a bit. I tested the decompressor valve and it does suck closed so I'll assume that it works. This blade holder has the nyloc nut but there was no washer so I used a slightly oversized washer to take up the slack and get a tight fit.