OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Victa Lawn Mower Frames Identify Victa Pro 550

I've just put the coil back on and there still isn't any spark with the cut out lead off. I'll connect the oscilloscope with the secondary pickup & see if there is any voltage being produced.

Very odd as it technically should have spark.

The flywheel magnets are still strong enough as well.

The owners explanation was that it got harder and harder to start and then wouldn't go at all.

Attached below is a picture of the oscilloscope waveform with the original coil.

The secondary voltage is only 2.42KV



I then installed the NOS coil and the secondary voltage rose to 5.86KV



What is really odd is both coils test the same with the multimeter.

After some strenuous pulling of the cord, it backfired and ran up to governed speed.

It will cut 6" tall faster than you can push without missing or backfiring.

However, once the engine is turned off it refuses to start until 30 odd pulls on the starter cord. It then pops back through the air filter and slowly builds up to speed and then runs perfectly.

Is this more of a carby issue or still an ignition problem? Maybe the module?

Also, what is the maximum revs it should run at? It sounds like it is running twice as fast than our Victa Power Torque engine. It definitely leaves the Power Torque for dead!

Could the starting issue be the result of not connecting the hose to the vacuum control button on the cowling? This probably explains the high revs as I didn't have the cover on with the hose connected when I was testing it.

I can't obtain a replacement ignition module locally, so would need to order one in and then find it isn't part of the problem. The NOS coil I purchased could also be faulty.

More testing tomorrow...

The fact it runs makes me think the ignition side is ok, I would be leaning towards the carby with the hard starting, these can be a pig of a carby but once sorted they are very good

Yes it runs really well when it is going - no surging nor missing etc and pulls well under load. I'll pull it off tomorrow. How do I disconnect the throttle cable from the carby? Or is that only possible once it is apart?

LRT, the throttle cable is a bit tricky but once you know it is easy, problem is I'm not sure what you will find wrong in there, they are a great carby but I have to modify them to get them to work properly and that isn't easy to explain here. Anyway to get the carby off you have to twist it towards youand then pull it away from the barrel, be gentle with it. Move the throttle to run and remove the kill switch pin through the side, then you can remove the center wire/pin. Remove the snorkel hose and you will see the cable where it attaches to the carby body. Move the throttle control to the stop position, lift up the cable where it enters the carby body and pull it back out and it will release from the cam inside. Not easy and then once you have it apart, I will have to explain how to put it back together Go easy on the way the cable connects to the body you have to be forceful but delicate

Hi Norm,

I have removed the carby and disassembled it. The diaphragm spring is badly distorted, so I managed to track down a replacement to install.

I have a new poppet valve (part no.: CR03593A) on hand. Do I replace the existing one even though the existing valve looks ok? Also, what letter on the poppet valve should I line up on this mower?

I also have a new diaphragm. (part no.: CR03635A)

Caleb

Hi Caleb, I guess you have worked out that you need a plug socket or similar up inside the throat of the carb to hold the poppet up so you can remove the retainer disc. Then you can remove the diaphragm , spring and lifter. This then exposes the cam which you can lift out. I doubt you are going to find anything in there to cause the hard starting but you will have an idea as to how it works. I cut the lobes on the cam down and I have no trouble getting them to start, I'm not sure if cutting the lobes down makes starting easier, but it works for me. The re-assembly starts with the cam in the carb body, in the closed position, cable hole closest to the entry point of the cable/snorkel,throttle cable fully extended in the run position,poke the cable ball in though the body and clip the ball into the cam, rotate the cam full to the left and the cable will be sitting in the slot in the cam. Then clip the cable outer back into the carb body from the outside into the little recess in the body. Next comes is the stupid kill switch that I always fit a new rubber to and it often takes me several attempts to get the thing to work and even when I have them working they are prone to fail. The kill switch was just another one of Victas not so finest moments. If you have got this far then you can refit the carb to the motor. Then the next issue you may encounter is the float needle, I'm pulling my hair out with those at the moment. Good luck

Caleb I just saw that you can remove the center from some of those end caps, I had not noticed that before

Thanks Norm,

I've just finished cleaning it. No I didn't need a socket. It only needed firm finger pressure to hold it.

Are these the lobes you cut down? How much do you remove? I'll reassemble the carby and try out the mower first so I can see if the new diaphragm & primer cap fixes the problem.


I have also bought a cam (CR.03626A) that looks identical except for a pin moulded on the arm opposite the hole for the throttle cable. Is this an updated design? The existing cam part number is: CR03406

Caleb there is probably 10 different cams I have seen, Victa was obviously to solve the problems with them. The lobes I cut back are the ones the lifter runs up and down on, as you can see the poppet is shut and then it drops down sharply into the "V" so it goes full throttle. By gently sloping it back you can control how far you want the poppet to open and this controls the revs

Thanks Norm. I've just put the carby back together with a new diaphragm, primer cap & main jet. I'll let you know once I get it back on the engine how I go. Caleb

Something I forgot, the "C" on the poppet faces the inlet from the float bowl section

I've just re-fitted the carby. However, when I put the earth pin in with the throttle set to half way, it jams everything up. Is this because I am pushing it in too far?

As I said not one of Victas smartest bits of design work, get used to it you will probably have the carby on and off half a dozen times trying to get that sucker to work. Just pull it back out and see if it frees up but I doubt you will get it to work as a kill switch without replacing the rubber, but you have to leave it in there because without it the cam can come around too far and release the cable

Ok thanks. It still won't start. The oscilloscope still says the coil is producing 5KV but plug isn't sparking - even with heroic cranking. I guess I need to find another coil & module. I don't think they're going to be able to mow the lawn before Christmas at this rate.

But you had it running before so the coil and module should be fine, pull the kill switch wire that goes through the side of the carby, you can never trust those. Heroic cranking isn't going to help, if it doesn't want to start it won't

Hi Norm,

There is still no spark with the kill switch pin removed from the carby and isolated from any potential earth.

There is no resistance between the coil mounting and the spark plug.

However, there is also no resistance between the earth lead and the primary terminal on the coil - even with the primary lead disconnected. The resistance between the primary and earth terminals is 1 ohm.

This is very puzzling as I would have thought that would short the coil out.

I would also think that if the timing was out it would still produce a spark like a Briggs & Stratton will when it has sheared a flywheel key. However, Victas may be different.

The other thing worth noting is that the flywheel has a noticeable horizontal runout that runs to 1/4" on the flywheel rim. This seems to indicate that the crank has been bent.

Maybe this is the problem, although when I set the magneto air gap it was even on all three legs when spun past the two magnets.

Caleb

Ps. I can see why they go to the tip!
Especially as todays shop labour would be more than it is worth.

Not the timing because you had it running, only way to check if the crank has runout is at the nut, if that oscillates at all then you can tell the crank has issues, but you had it running and you didn't mention any vibration issues. At the moment the issue is with the spark which was working yesterday before you started to work on the carby. You are right, one hour in the shop would be a lot more than they are worth and that is without any parts. Problem is when you get them running they are much better that the Chinese rubbish on the market now, I had a mate ring me up a few minutes ago, his brother wants a mower, he had bought some Chinese thing 2 years ago and it has fallen to bits and he is not interested in going that path again

Yes Norm, I was telling the owner that although a new Honda is easy to start and quiet when new they just cannot handle the heavy grass like a 2 stroke. I can mow grass three feet tall in two cuts whereas the Honda mowers stall. Also, the trendy new John Deere ride-ons cant handle much more than a suburban lawn either.

The mower ran after installing the coil but after letting it sit under a minute it then required a good 30 or so rapid pulls to get it to fire again. I then dismantled the carby to see if this was the cause of the hard starting.

What I probably should do is put the carby onto the Power Torque engine and mow some grass to rule out any problems with it.

Yes the crank and the nut has a major horizontal wobble when rotated. I also can't feel any play in the bearings.

It does vibrate, but no more than the later Power Torque engine I use every week.

When it does go it will handle 1 foot tall grass without dying.

Unfortunately, the only spare Victa engine I have is an earlier full crank engine (with plastic carby) that I rescued from scrap a few years ago. It has the earlier magneto with points. The engine is currently dismantled as it was seized up when I got it.

If the old points type magneto on the spare engine still works, can the later system be converted back to points? Assuming the mountings are the same of course!