OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Brass washer dimensions for G4

My 160 Mustang that I rebuilt last year is running great but the revs do seem a little fast. Got a cheap tachometer and currently running around 4000 when full governed.
Want to get a couple of those brass washers to bring the speed down a bit but don't want to import from Aus.
Can anyone tell me the size of the washers so I can source here and that 2 will bring the speed down a couple of 100?

Hi SR,
long time no hear. I thought the washers only help to achieve a low idle.
Have you checked that the diaphragm is sealing around the edges or the motor isn't sucking in air where it shouldn't such as the inlet manifold. Have you checked the condition of the manifold O rings? That is a known cause.

You should be able to use any washer that fits over the shaft the cam sits on as long as it's about 1.6mm thick or slightly under. That's what I did to one G4 plastic carby and it worked fine. I actually combined two to make up that thickness. It can be more challenging to fit the tiny ball end of the throttle cable back on the cam so best not to exceed 1.6mm. I'd either buy a vernier caliper or borrow one to measure the washer's thickness with accuracy.

Any pics of the classic? So glad you revived him on your side of the planet!

The washers can have a bit of effect on the top end, but as MF says, more at idle.

I just use a regular brass washer from the hardware store with the hole slightly too small (you won't find one that fits spot on) and then file out the centre

Will try to find the box with the size of them

G'day Tyler,
Is it's thickness close enough too? Why brass? I used galvanized steel ones.

I think because brass is smoother and wouldn't gouge plastic as easily.

They are a bit thicker than the genuine ones (maybe 3 or 4 genuine to the bunnings ones I use) but they actually get the top end down.

That Mustang Vortex I bought a couple months back - came with a genuine washer in in - idled at the speed I would normally mow with and revved out closer to 3700 (no air leaks). Put in one of my washers and top end come down to 3100 something, but I will have to do the mod for the idle stop screw as it idles so low it will die.

But I am the only one who uses it so it doesn't matter for the moment.

Did you have too much trouble getting the ball to locate and operate the throttle?

Good to know it can have that much impact on revving.

No effect with anything up to 2 of these washers, then problems

G'day SR Mf and Tyler

I mostly have the poppet valve set to the C position then use a couple of hole punches on a VHT paint
can lid to make the washers ,after the washer is cut out I slightly file down the sides to make the
washer a smidgen thinner and to deburr the washer ,I guess if you use a cheap plastic from something
else it may disintegrate .



Cheers
Max

Many thanks all.

It's been going strong since last summer.
Tach also has a run time on it which I'll check how many hours it's done next mow and I'll get some pictures.

I recently reset the points properly with a gauge as originally I just estimated. Since then the speed has gone up it seems.
Hopefully that means it's burning fuel better.

Haven't taken the carb off to check the manifold o ring, will do it all together but it seemed in fair condition last time I checked.

Vacuum control seems to be doing its job, if I twist the button (either way) speed goes up so at the limits of the govenor.

Guessing the diaphragm is good, seemed fair condition too when I rebuilt it. Maybe worth mentioning, the diaphragm isn't like any of the ones I've seen pictured, it's not thick rubber, it's some thin material like the decompressor diaphragms are made of. Bit weird but seems to work.

Think I must be fairly lucky with this Victa, seen the other thread on modifying the cam. That seems a bit drastic and makes it non- governed?

I'll get some brass washers ready for when i pull the carb off just incase. Making your own from plastic is a good idea, not sure if the plastic would degrade. It's a G4 carb, black poppet, so no adjustment in position of it.

Idle is a little fast, washer should raise the height of the cam reducing speed at idle and full but I suppose how much comes off each is also dependent on the springs.

Thankfully, I have the G4 with the idle screw adjust so if a washer brings the idle too low I'll be able to adjust.

I never managed to find a catcher for it so am soldiering on with the original. Patched up with aircraft tape, fibreglass tape, epoxy and prayers.

If I had the time I would make a catcher from sheet metal like the really early victa mowers had, next year maybe..

I've taken to running it with the plastic cowling on, it's pretty cracked and would only get worse without some TLC.
I made a strap to secure the fuel tank in it's original position. You'll see in the pictures when I upload some.

Big delay but it seems successful!
Just 1 washer, didn't measure but must be around 1.6mm.
Idle seems good and top speed is around 3660 which seems like a nice speed for it.
Pictures attached!

You've done well with difficult to source spare top SR and it's tidied up a treat. Hope you can find the cover and a better catcher one day. Keep looking. They're out there. You don't have to use that exact catcher.
Nearly all thumblatch designs will work on that base casting, except from any self propelled models, the Victa Twin or the Victa Compact. The original shape like yours would be the most desirable of course.

Main thing is you got what you have in sound order. The mower itself looks in great condition!