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

What year would this Victa Professional 550 be?

The model number on the air filter is: WQ 197EX9

Is the motor the original fitment or an older retrofit?

There is no spark produced form the magneto even without the kill switch lead. The coil resistance is 9 ohm.

Are parts still available for this engine? If so, is there a parts list?

Does anyone know if the later c1990's victa power torque engine will fit the base?

LRT

Ps. How much compression should be expected with a Victa?

The engine spins over by hand easily and the compression stroke is barely distinguishable when spinning the flywheel by hand with the cover off. There is no compression rebound whatsoever.

Should be a decomp valve under the cover, I can't see the decomp tube coming up from the carby so anything is possible. Remove the cover, remove the decomp if it is there and put a spark plug in the hole and then see what compression is there

Hi Norm,

Thanks for your prompt reply.

Yes it does have a de-comp valve under the cover. I'll do what you suggest tomorrow & get back with the results.

When turning the engine over, it looks as though it has a bent crankshaft.

The owners description was it got harder & harder to start & then finally wouldn't start at all.

Caleb

those motors used a longer crank than a regular 18" engine, what makes you think the crank is bent?

When turning the engine over, the flywheel and centre of the shaft has a pronounced side to side wobble. There is no side play as if the bearings have worn.

I haven't had time to have a proper look at it yet though.

Caleb

fair enough, they are simple enough to strip and rebuild,
does the height of the blades vary on rotation ? ( from side to side )

No there isn't any noticeable height difference between the blades when they are rotated. Can you still get piston rings & the magneto from Victa?

G'day LRT, and a warm welcome to the ODK Forums.

From that model number, it's 86-87 year of manufacture; it's actually the 'Pro 550 Self Propelled' model. One of the very last of the full-crankshaft Victas; most of the model range had gone to the half-crankshaft PowerTorque engine by then. So it's the original engine I'd say, and no, a PowerTorque won't fit it.

Most parts are still available for this one, with the exception of the decompressor valve assembly. However, if that one has three clips holding the diaphragm chamber together, rebuild kits are available, e.g. HERE.

Piston rings are available in standard and three oversizes. That said, it's fairly rare for Victa 160's to get away with rings only when they're worn; the bores tend to wear oval, and they need to be rebored.

The basic service info on the engine and carby is available in the numbered sections HERE as free downloads; the lower 'Attachments' docos require a paid subscription for access.

This engine has electronic ignition; if it has the separate electronic module, the problem could lie in either the coil or the module.

Thanks Gadge,

Yes it does have a module that appears to have been replaced recently.

How to I test the module?

The coil resistance is 9 K Ohm.

Caleb

Try removing the coil from the body and clean where it attaches so that it gets a good earth and the module needs a good earth as well

Hi Norm,

I've cleaned all the contacts & checked for a good earth but there still isn't any spark. The module appears to be fairly new. Do the terminals on the coil have a polarity? The mower had been to several shops before I got the job so I don't know if things are connected up correctly.

Will a Victa MAO5617 universal module work?

http://www.gaspares.com.au/program/...20902102&GROUP=MW%20ELEC%20ECP%20VIC

Not sure if that module would work with the coil, probably would, but if you say the one you have looks fairly new I would think it is probably ok. Seeing you tested the coil I guess the plug lead is ok. Very annoying when you don't have boxes of bits to mix and match with to eliminate each component. Makes you wonder why it has been to several mower shops, I guess they figured it wasn't worth their time. Problem is once they start replacing bits the cost plus labor add up very quickly. Have you checked it for compression yet? I probably have a few of those motors kicking around here, quite a few I have never looked at so not really sure what is there, always happens when you pick up bulk mowers from ebay or gumtree. They just get pushed further back into the shed

There are basically two resistance readings for the coil; plug lead to earth or primary terminal, which should be 8.5-9.5 k ohm; and primary terminal to earth, which should read 0.2-0.5 ohms [if the meter will read that low].

The resistance across the module seems to measure around the 4.5 - 5.5 k ohm range.

The plug lead to primary or earth terminals: 9.0 k ohm

Between primary and earth terminals: 1 ohm

Between terminals on module: 4.5 k ohm

I purchased a NOS coil and it reads 8.5 k ohm on the plug lead to primary or earth. Otherwise it reads exactly the same as the current coil.

Does it matter which terminal is the earth or primary?


I haven't put the compression gauge on it yet, but it feels as though its got about 80 psi or so with the decompressor replaced with a spark plug.

Secondhand Victa's are virtually non-existent around here.

Caleb

Ok so dumb question what about the kill switch in the carby, pull the wire off that goes through the side first and the one through the rear second. You also need the throttle in the run position so you can pull the center wire out

Unfortunately Norm, both leads to the carby were out when I picked it up, so I don't know which goes where. There is no spark with the leads disconnected & isolated.

Just noticed both pins are different & can't be interchanged.

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!

Another option is to swap the crank from the older engine if it can fit the later flywheel. Otherwise I could just reassemble it with a quick hone & see if it has enough compression to run.

Can I convert the older magneto to use the same electronic module as the later version if the points are past salvaging?

Caleb, so many questions my head is starting to hurt. Fitting the carb on your powertorque is a good way of testing it, but at this stage you are saying you have no spark and the crank seems bent.Swapping bits around can be difficult with the ignition, internal coils/external coils, how to mount the points, gets really ugly, if you were a bit closer the problem would be an easy fix because there is a pile of stuff here you could use, but a lot of the stuff here is pre plastic carb

Yes Norm, I cannot understand why there isn't any spark. It is becoming a major headache. I think the owner said last year it was away at a shop for nearly 6 months!!

Thinking last night, although the crank is bent, when it does run it runs really well when it starts. It just won't restart until you are physically exhausted from cranking it over. I normally associate that with 4 strokers as all the Victas I've used are generally reliable.

Thank you for your help with this as it is absolutely mind boggling why it runs well but hasn't any spark when trying to restart it. I wish I had another engine with the same ignition system so I could test it.

Another silly question, what sort of air gap have you set it at 10 thou or about that? I do have a few motors here pre powertorque with plastic carbs, but I have never even looked at any of them,I like the powertorques so I concentrate on them. There is no point in pulling a motor till it exhausts you, they will either start or they won't. The beauty with the powertorques is spark on them is usually very good and rarely gives trouble

Hi Norm, I have tried setting the gap to around 10 thou with a business card and also tried it with the armature legs just touching. I'll re-set it with a feeler gauge to double check.

Hi Norm, I've got it to go!

I took the plug out and sat it on the magnetos base plate and span the engine over with the air drill. There is a spindly little blue spark every 30 seconds when rotated at 800rpm. I then closed the plug gap down from 24 thou to 6 thou and now it produces a spindly blue spark on every rotation. It seems way too weak compared to other magnetos I've tested.

Now I'll put the decompressor back on and see if it'll re-start when cold.

It won't start with the decomp valve installed. However, there's fuel leaking from the head gasket so that probably explains why as the compression would be too low. Once the plug is wet, it won't go until it is cleaned with contact cleaner. Then with a few backfires, it eventually runs again. I could lightly flap disc the armature where the coil goes over to see if I can get a cleaner earth. Otherwise, the spark is too weak to support combustion. I guess the reason it will restart just after it has been turned off is the hot carbon deposits ignite the fuel & kick starts it until the spark can take over! A bit like a pilot motor on the old Cat bulldozers.

Edit: I've cleaned the armature and noticed it is spreading out at the back. Maybe this is the cause? I can't really fathom what the cause of the weak spark is. Cleaning didn't make any difference.

Pity, I have plenty of head gaskets here and that is most likely the cause of the no starting. A thin blue spark is all you need. The fact you have fuel coming out the head gasket indicates it has a lung full of fuel and you need to leave the plug out and give it quite a few pulls to clear the fuel out. Not sure what sort of material you have down there to make a head gasket out of, just to see if this is the cause. You did check that the decomp valve was working, I can't remember if we discussed that earlier, bit of tube on it and give it a suck and the valve should close, if not it is not going to work

Hi Norm, I can get a NOS head gasket in town. Yes the decomp valve closes and holds when on a vacuum pump. I'll try the head gasket next. I hate throwing parts at things as it gets very expensive!

Edit: what plug gap should I set it to? It cannot jump the gap at 20 thou with a clean plug.

Something is not happy if it won't jump a 20 thou gap at atmosphere pressure. I guess you could cut a head gasket from a Weeties packet, might not last but you would at least know if compression was the issue, oil it up both sides and see how it goes

Hi Norm,

I've cut out a gasket using thick gasket paper and PEP gasket cement. I then torqued the nuts to 15 Nm. It still won't start with the decomp valve fitted. When fitted with a second spark plug blanking the decomp port it will eventually fire as long as the plug is cleaned with contact cleaner every 3 pulls or so. When it does run it revs up to governed speed and cuts out and then it backfires and stumbles and then it blows the head gasket. It must have cut a groove in the head. I've made two gaskets with the same results. All I can do now is skim the head with some wet & dry paper and try again.

I found another coil & module, but it makes no difference. When I put the plug on the power torque engine and crank it, there is a nice blue spark. Maybe the coil isn't receiving enough magnetic induction. I can't get a new E armature locally to try out.

I wish the base enabled a power torque to be fitted.

Problem is as I said I have plenty of those motors with that bolt pattern but most need the pre plastic carby and internal coils/points and I'm out the eastern side of Melb. Don't give up on it because it will end up a good slasher/mower

looking at that barrel , my guess is your working with stuffed
piston, rings...

Hi Norm,

I also have a points style motor but the PTO end of the crank seems to be different to this one. It has the cup flywheel and the internal magneto with points and plastic carby. Maybe off a Corvette?

What is puzzling is that it should produce a spark as long as the flywheel magnets passes the armature. It only produces a spark occasionally when cranking but doesn't hit and miss when it does actually run. Maybe the bent crank is the culprit? Still it can run and handle a lot of load as I worked it really hard to see if it died.

I'm going to be out baling hay most of tomorrow morning so will have time to think on it!

I remember seeing an old green Victa with a catcher outside a scrap metal place and when I came back 15 minutes it had been taken. I've asked dealers and repair shops within 70 kms from here and strangely no one has a second hand or even a wrecked Victa for sale.

Caleb

Yes Squizzy they're fairly bad. Still I have seen old Stihl chainsaws that look far worse and can at least produce a good spark!

The odd thing is why the spark is so weak.

Two replacement coils and a new module hasn't made any difference, which rules that out.

Here are some pictures:

Some things to ponder...

What is the bore reject dimension? 3 thou like a Briggs & Stratton?

Also what should the ring end gap be?

Can you still get new cranks to suit?

Edit: Just noticed it says Power Torque key start. I must be getting brain fade....


This flywheel has magnets 180 degrees apart. The one I'm working on doesn't. Is this an update or for another model?

Note it has the ring gear for a side starter and the magnets are level with the fins, not underneath.

http://www.mowersgalore.com.au/spar...ay/4642-victa-power-torque-flywheel-key/

the top pic is of a powertouque flywheel, goes under the motor,
wont fit your 160. and man.....that bore/ piston is r#tsh*t,
dont waste your time till you can replace / bore those.
cheers pete

Pete, the issue with this motor at the moment is not the bore, it is the intermittent spark that is confusing, in the words of Julius Somner Miller, "why is it so" Any way I have plenty of barrels and pistons kicking around here as well as new rings so somehow we will get this back to its glory days. Do you know if the earlier impulse start barrels will fit the side pull, I'm assuming they will, because I have a pile of those here

Hi Norm,

Does the flywheel on the engines fitted with the impulse starter have a cup with a nut on top of the flywheel?

I've got a scrap Victa that was seized up and this one has a cup that goes on top of the flywheel. Visually the barrel looks the same. However, the crankshaft is tapered to suit the older flywheel with the internal magneto and won't fit the later external magneto type flywheel. See the pictures below:

Flywheel off older internal magneto engine:


Comparison between older crank on left:



Comparison of older barrel on the right:



Once the flywheel nut is loosened, there is a noticeable wobble between the flywheel & the crank, which would no doubt upset the timing quite a few degrees depending on where the flywheel was sitting on the shaft when the nut was re-tightened. The flywheel came off the shaft with very little effort. Note the aluminium flywheel mounting doesn't show any signs of fretting against the steel shaft, even though it is a loose fit.



When testing the runout of the flywheel end of the crankshaft with a dial indicator, it indicates a deflection of 40 thou when rotated! Maybe this is due to a mechanic levering off the flywheel unevenly?

The crankshaft end float is 2 thou. This amount of float seems acceptable.

What is unusual is that someone has applied liquid nails over the top two crankcase bolts. Whether this is to fill a crack or to stop the bolts from turning I'm not sure.




The flywheel magnets are flush with the aluminium casting. I don't know if these have been worn down or not.




The lamination stack that makes up the coil armature is used instead of a single piece of iron to reduce eddy currents, which reduces voltage output & generates excess heat. Maybe once the small air gaps become filled up with rust and dirt it reduces the cooling ability and causes eddy currents that further reduces the coil output?

hi Norm, and sorry mate, the issue with that motor running in it's
present state is the bore, in that condition, it wouldn;t run if you plugged
Hazelwood into it....so until that is addressed, your wasting your time,
sorry LRT, all the other swapping around is not going to gain you a thing.

Caleb, I just remembered that the early impulse barrels here will not fit the plastic carby. You are overthinking the whole thing. What is it you want to do with this mower, use it for mowing or wanting to restore it to original. And squizzy I wasn't planning on plugging it into Hazelwood, because once this mower is running again, it will be running much longer that Hazelwood will be

Norm,

The owner only wants it to use it to cut grass so it doesn't matter if it isn't correct from a restoration point of view. It can have another engine as long as it fits the base. This may be a better option in light of the crank being bent.

I've got it to run a few times and in its present condition it even leaves the Greenfield ride on for dead in the rough. Not to mention a four stroker!

It just would be handy if it could produce a spark on every revolution...

LRT, you ignore the basics of mechanics at your own peril...
and Norm.....they both could be lying idle for a long time!!
hahaha

Yes you are right that you need good compression for an engine to start and run properly.

However, the main problem with this engine at the moment is the spark cannot jump a plug gap more than 6 thou in the atmosphere with a dry spark plug. Until the ignition system is fixed it's not really worth rebuilding the rest of the engine.

As I said I have a few sidepull motors here, I haven't looked at them but I would expect they could be got running without too many issues, I just don't have time to bother with them at the moment, too busy fixing powertorques

Thanks Norm. Caleb

Thanks to Norm's helpful advice and supply of a rebuilt engine, the Victa 550 is now 'turning grass into lawn'.

With Norm's carby modifications, it now has proper throttle control and starts with one gentle pull. The owner is delighted.

Diagnosing this faulty mower engine was a challenging experience to say the least! I have learnt heaps. My thanks to everyone who answered my many questions.

Looks good Caleb, glad to be able to help keep a real machine like that doing what it was designed for

That looks beautiful!! Shiny motor on a base with character lines is actually a good look and ready for work!!