OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Victa Two Stroke Engines Is it worth it? Mayfair

Tested it and still 0 on compression gauge, other mower with decomp in reads 60. How can i have lost all compression, there is no air leak anywhere and everything is tightly connected????

The cylinder may have to much wear and broke
a ring ?

Took the carby off as well as muffler, rings are ok, piston looks good. I only feel reistance once for every rotation ie the second bit of resistance is fairly weak. It's like i've forgotten to tighten something but i dont know what. I guess i've got to take the engine apart again, does this mean i'll have to replace the gaskets as well, i replaced them a couple of weeks ago? The connecting rod seems a little loose, dont know if it should be connected more tightly to the crankshaft?

Before stripping this down i took the blade plate off, i cannot see a problem with the bottom crank seal but there is slight play there ie if i grab the boss there is some movement there. I'm guessing that the bearing could perhaps be replaced but could this account for a zero reading with compression?

hey,
sounds like the cylinder compression is down , play in the bearings is quiet normal for these engines wont do any damage , because there is fuel getting to the cylinder i still say the crankcase is fine, especially since you found no compression in the cylinder, so i guess its barrel off again.
also conrod play is also normal.
im thinking that the clearance between the cylinder and the piston is excessive and the rings are failing to seal the gap.
dont reach for a drum of fuel and matches yet.

Hi again Mitch, I've read some other websites listing causes of no compression and most say the conrod. Mine is ok, moving the flywheel moves the piston and no strange noises either. You might be right about the clearance between cylinder and piston, a look through the muffler does show a bit of clearance but as you know I changed the rings and the mower did work for a while. What do I do now? And also let me know when I can the fuel and matches out, won't you.

haha don't let it beat you !

sounds more like clearance to me ive never had any conrod issues.
i guess if it is clearance that's the end of it unless you want to get a rebore

Mitch or anyone else, do you know of any specs/tolerances about what is acceptable size for a cylinder bore compared to piston size for a victa?

might have a spare barrel n piston here somewhere , 125 if i remember ? where abouts in melb' are you im on my way down there after the 14th for a break i could drag it with me if it might help maybe have a bit of a looksee too , a hand never hurts most times

G'day vccomm, I'm out in the Eastern suburbs of Melbourne about 15 km out from the city. Really appreciate the offer but I don't know if the mower will last that long. I have an angle grinder aiming straight at it ready to demolish it. On the other hand I'd really like to know how this thing could lose all its compression so quickly, it took so many hours to get it going and then probably ran for about 5 or so mins in total and now nothing. Keep in touch and let me know your movements. It is a 125.

no worries , yeh got me tossed too !! but it cant be all bad , i'll be around mooroolbark ish i'll pm bfroe i leave n see how its going and you need a different disc for alloy haha cheers

Ok Vccomm, let me know when you're around, I'm about 15 min from Moroolbark. I still reckon a bonfire might be the way to go. Somehow the compression is all gone but I'll be blown as to how this has happened.

might just be the decomp' valve . no worries though sounds like ... as always a simple fix , easy to miss some things . so dont burn it just yet

Not that easy, replaced the decomp with an old spark plug and still no reading with the compression gauge.

Met up with Vcomm who was over from interstate. Great knowledge of these mowers and a top bloke too. Quickly diagnosed the problem which was a blown head gasket (brand new gasket too), then proceeded to blow my mind by making a gasket up from some cardboard. He then got the mower to fire up, amazing! All this was done in poor light with minimal tools but this guy knows his stuff. Thanks so much Dave

Hey tiger.
how does it run now ? Easy to start .
carby doing its thing or is it perfect ?
Glad you finally won.
mitch

Bit early to tell mitch, there wasn't much petrol but it fired up, i'll test it soon and let you know. Its still mayfair 1, tiger 0

i disagree , the fact that its run makes it mayfair 2 , tiger 3

and good fun it was too, left the plug in yours out of the masport ! . it was a fix to see if it ran though , it should be ok for a little while but it still needs replacing at least its an easy fix now . good to meet you too tony . did you get it fired uo properly yet ?

I realised it was your plug Dave when I tried to start it up tonight. Changed the plug, the mower starts, runs for a second or 2 and then dies, I go through the cycle a few times, it always starts but won't go beyond a second or two. This all suggests the carby is at fault but I've cleaned it umpteen times already. Other problem which it now has is the starter squeals when I pull on it and it makes a rumbling sound as well some of the time when I pull the cord. So no, not quite there yet.

the squeeling might be from the bracketson rear of coweling bent a little ? check the primer on the carb' didnt seem to be working well coulndt hear anything from in there , . joking about the plug too keep at it mate you will get it soon . soooo close now

I'll check the bracket near the cowling tonight, I thought the tickler was okay though, the petrol seems to flow easily enough. The mower keeps starting without me having to prime it, that suggests that there's enough petrol in the carby to start up, just doesn't go anywhere after it fires up. I prime it till the petrol flows and then it starts momentarily and dies, then I start it again, same thing happens, and again.... Have not tried keeping my finger on the tickler yet but shouldn't have to do this, and I know the carby is clean.

would you like me to send you a carb i know works well ? send yours back and i'll give it a once over ?? its from the excact same machine too and did run well no problems . then that problem is eliminated once and for all , if the cowel is bolted down properly the starter wont slip . you replaced the decomp' or blocked the vacum port on inlet ?

Thanks Dave, let me have one more crack at my carby and I'll let you know, I did replace the decompressor, I had to because with the proper compression (now that the head gasket) is right it was hard to pull on. Will let you know asap about the carby.

sure , let me know . pm me if needed

Gave the carby yet another clean, the starter mechanism was squealing so I lubricated a few places and that's quietened it down. Put it all together and it sounded healthier, it took a few goes but it starts and runs, it stalls after 10 or so secs. It never reaches full revs ie missing here and there, it wants to keep running but it just doesn't quite get there. It was getting late so I had to stop. Getting closer but not getting that nice continuous revving that it should have.

with a lot of smoke too ? might just be so full of old fuel and oil by now , it was really wet inside . keep at it it sounds promising now

A little bit of smoke but not that much, the carby was pretty dry as I dried it with the air compressor after putting carby cleaner through it.

Tested it again this morning, pretty much the same result. Starts every time and runs for a few seconds but then seems to gasp and conks out.

Gave it another run, same result. I notice there's a lot of oil/petrol coming from the spark plug hole. I guess there's been a build-up of it and a good run would clear it but if I can't get it to run longer than 10 secs, is there a way of clearing the old oil/petrol without taking the body apart?