OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Victa utility 160

I have a utility 160 that I have been using and repair rebuilding ect. My grandfather cut the grass with it at home and at his jobs for over 40 years. It worked fine and now it is always blowing a head gasket. I have took the head off and placed it on a flat marble and polished it with 400g sandpaper to make it flat. it blows on on startup however runs and then will not run agin when turned off. Could this be the wrong spark plug as I don't have a cj8 in It and have a random bosh in it. should I use gasket sealer instead of a head gasket? Also, what is the best way to remove a head gasket as I find it hard not to scratch the head so I take off as much as I can and then use the sandpaper on marble to get rid of the the rest.

From Dean

Hi dean,
Put a straight edge on the head and have a good look. It hay have rounded edges..... Maybe us a mirror with 400 paper..
As it's getting old, probably compression is probably down a bit. I don't use sealant on head gaskets. I scrape old gasket off with a snap off blade... even a wire wheel...
Get the right plug...
Tighten the head down, and a second time after a couple of hours use. If you don't have torque wrench, tighten it firm, before stripping it.
I'm putting one together tomorrow.........
good luck
speedy

G'day Dean and Speedy

Yep what Speedy said ,I wouldn't normally use a wire wheel on alloy as a lot of the wire wheels are too abrasive but soft wire
wheels are available.

List of things to take note of if you haven't already .

1 flat marble may not be flat enough , Speedy mentioned a sheet of glass and I agree that would be better.
https://www.acousticguitarforum.com/forums/showthread.php?t=295473

2 When sanding use a figure 8 pattern.


3 Use a straight edge (flat steel ruler will do) then a feeler gauge to check straightness. (a torch or light can also be used on one side of the straight edge while looking on the other side of the straight edge to see if light is visible)

4 Gasket should be a proper Victa head gasket or equivalent gasket paper not home made paper gasket.

5 you can use Loctite 3JA Aviation Gasket Sealant non hardening on the head gasket.

6 Check top of cylinder with the straight edge.

7 A new stanley knife blade will remove an old gasket , if you use Loctite 3JA Aviation Gasket Sealant non hardening
next time the gasket can be removed very easily .

8 Dummy fit the head on without the gasket ,nip the bolts up to make sure the bolt threads aren't bottoming
before the head is flush with the cylinder ,sometimes people leave flat washers off head bolts or bolts are
slightly too long or threads are rusted ,carboned damaged ,all contributing factors for the head not tensioning up correctly.

Sometimes a tap and die nut must be used to clean up the old threads.

9 Old spark plugs can misfire so a new plug is required to rule that problem out as a contributing factor for a blown gasket.

10 If the motor has points ,clean and gap them and reset the timing .

11 I would check your 4 crank case bolts aren't loose and the 4 lower cylinder bolts.




Cheers
Max.

What brand head gasket are you using?

I recall about a year ago a fellow mower mechanic mentioned to me he put several head gaskets into one, flattened cyl head, etc

Changed brand back to victa genuine and problem solved.

I think they were jakmax gaskets

Thank you everyone for your advise. I will use glass and a figure 8 to flatten it with 400g sand paper. Anyone know where I can get a good gasket as I bought a set from the Chinese seller green acre mowers on eBay and they don’t even fit.

Mine being a 160cc it has a rod in the centre of the cylinder with the cup of the rod in the crank case. I don’t think the issue is it it bottoming out and being loose.

I set the gap a couple years back.
Do you guys think the issue is a bad gasket and wrong spark plug?

If it blows gaskets. Something is not flat. the barrel should not be warped as it is cast iron but check. Probably the head.... get good gasket and plug, try again.
cheers speedy

Get a steel ruler and place the edge against various mating surfaces and shine a light from the other side or even hold it against the daylight outside.

How can a gasket wrap? Should I locktite the nuts on the end of the head? I will give it a go tomorrow.

Oil both sides of the gasket and do not use Locktite

G'day Dean ,Speedy,Tyler ,Mf and Norm

I would prefer to use the Loctite non hardening gasket sealant than oil on the head gasket.
,the idea of oil is to make the gasket swell and stop the gasket sticking but sealant will give a
better longer lasting seal between the 2 surfaces.

I've used grease and oil on paper gaskets before but when sealants are readily available and work better ,then there are no good reasons
for not using a sealant. .


A gasket sealer offers extra protection against leaks. Holes or gaps between surfaces could create spaces for dust, solvents, or gases to get in or out. Gasket sealers ensure that the gaps between surfaces are filled to prevent leaks.
Gasket sealants strengthen the mating between two surfaces. Therefore, when used well, the seal becomes stronger and can last longer too. In addition, this also increases the longevity of the sealed parts.

The only Loctite I would use on these mower head bolts would be the Loctite non hardening gasket sealant.but that's up
to you if you use it or not.


Technically speaking you aren't meant to use metallic objects to clean alloy as they can scratch the alloy.

Never use a razor blade or anything that could scratch the surface. Any scratches may provide a channel or means for fluids or gasses to leak through. Use a brush or scrapper made of plastic or nylon, although it is probably best to use a chemical cleaner.

I have found no problems when using new metal scraper blades, if you're careful.

Cheers
Max

Hi all,
would soaking it in detergent or degreaser solution soften the stuck gasket material enough for an old credit card to get it off?

I have ordered the parts so hopefully I can give it a go next weekend thank you everyone for your help. I will find some glass as well.

It would depend Mf on gasket material composition and how long the gasket has been on and how long you
let the gasket soak before removal, also on what type of sealer was used if any.

Sometimes you can use a brake clean or carby clean to dissolve the sealant /glue so the gasket
can be more easily removed.

Even proper chemical cleaner can need a lot of soaking time.







Cheers
Max.

im going to rebuild it now. I will resurface the faces on the head, cylinder, and crank case. I will change the oil seals as well. anyone have any tips on how to line up the case so the cylinder meets it flush? should I be putting any sealant between the two cases where they meet? if anyone has anything else to add on how to rebuild it it would be much appreciate. thanks

A steel ruler can be used as a straight edge to line up the barrel mating surface on the crankcase then tighten the crankcase
bolts.

I use the non hardening Aviation Gasket Sealant between the crank cases if they are straight if not you would
need to sand them flat but very rare for them to need sanding.

I know some people don't use anything between the 2 crankcases on a mower but I just do the same as a bike motor
and use the Aviation Gasket Sealant and haven't had a problem but lots of other products could be used.

https://www.accessnorton.com/NortonCommando/crankcase-sealer.24648/

Cheers
Max.

do you guys think is should change all three bearings whilst I have it all apart?

Hi Dean,

You may as well change the bearings ,it saves having a problem later on ,and not too expensive to replace.

https://www.outdoorking-forum.com.au/engines...ttom-crankshaft-bearing-ha25002a-160-001

Cheers
Max.