Seamus

Thanks Spud

I got some 280 grit w/d and have been rubbing the bore and it has made some improvement - see photos. But above the exhaust port the grooves are deeper especially on both edges of the exhaust port.

After a lot of rubbing there was no improvement in these grooves and I don't see them coming out. Don't know how well the photos will show this.

GHS has a compatible P&C kit for 50/51 saws and they both share the same crank case part number do reckon a 51 kit will fit buy check both saws stroke first.

 

I do think that plating will be ok, it may be thin but it is also bloody hard:thumbup:

Thanks Spud

I checked the specs and all the 50 series have the same stroke.

I have spent the last couple of days on and off applying the acid to the pot. There is a slight improvement but there are grooves in the liner which will not lead to a satisfactory performance in the end. I could probably improve it a bit more but it is going to be around the £30 mark to take a chance, and maybe that is better spent on a new pot and piston? Whatever I do depends on the MOT on my truck tomorrow which is bound to be more than I expect.

I am enclosing photos of the original and the latest.

If it is around 15% HCL, it is fine.

A bad seal won't smoke and the only way of testing is to use a pressure/vacuum gauge.

 

If the seals etc are leaking, the saw will seize again!

 

Fitting new seals is a case of removing the old one and driving in a new one. No crank case splitting needed:thumbup:

Ok - thanks

Note taken on the seal.

I will try the cleaning tomorrow.

If I do have to go down the new pot route it seems that the 51 is available. Are they interchangeable with the 50. The difference I can see is the addition of a decompression valve and maybe the piston is a mm or so larger.

I use the same method to lock when the cylinder is removed, it's standard practise for scooters. The Nikasil plating is .002" to .006" thick and is very tough and what look like grooves may be the aluminium deposit. Get some brick acid from Wickes and soak it for 5 minutes then rub it with some production paper as recommended earlier. It might take a couple of goes to get it all off but it's worth a bit of perseverance.

 

2

Thanks - I have a bit of that lying around - guess it needs to be diluted a bit.

The cylinder looks like it will probably come back, you need to find some caustic soda (Sodium Hydroxide) or acid Hydrochloric is good) and then give those damaged areas a wipe over with some wet and dry paper and use the chemical to etch of the aluminium - it should fizz well when doing this.

 

When it stops fizzing, clean it and rub it over then try again - if no fizzing happens. yoa have converted the metal to much softer aluminium oxide.

 

You can then rub the black shyte off with around 180 paper and then 400 to finish it.

 

I do use a cylinder hone on the bad ones but do it extremely lightly and find it beds the piston down well but if you use this method, don't go mad as the plating is thin on these cylinders.

 

The crank seals and ancillary rubber parts can only be checked with pressuresing and creating a vacuum in the crankcase, the play in the crank isn't a way of checking this.

 

The most common failure is the impuse connector from the carb back plate to cylinder and also the clutch side seal.

Thanks Spud

I have been reading up on Nikasil coating which I assume they used on this saw. The plating they say is so thin that any scratched will go through it. To me they seem to be too deep and it is unfair on you to ask to judge without seeing it first hand. If it doesn't work out then I have to start over again.

The carb to pot connection appears to be still a good fit.

I don't think the clutch seal would be the issue since the smoke was only coming out from the flywheel side.

I have taken the flywheel off and the seal looks good inasmuch there is no sign of any oil, nor on the back of the flywheel - I know not foolproof. If I do change that seal, can it be prised out rather than splitting the case?

There is one possibility of the pot to crankcase gasket. See green arrow on photo, where is might be leaking.

More photos enclosed. The last one in case it interests anyone, is my take on locking the piston to remove the flywheel or clutch.

The cylinder may be ok, I have a 95% success rate on them but it is a bit of a job and takes a bit of know how!

 

The aftermarket stuff is what you pay for,some OK and some awful. The Hyway stuff seems passable but I try to salvage the OEM part and fit a Meteor piston if possible.

Thanks - I will look those up.

I have now stripped it down so see what you think about it please.

I cannot feel any vertical play in the piston, con rod, big end. There is very slight lateral play, not the slide side to side, just very slight if you sort of try to bend the rod.

There is no play in the crankshaft bearings.

The piston ring is seized on the exhaust side, though I expect that would be expected. Would this account for the blow by creating the smoke via the flywheel?

Here are the pics. Exhaust is at the bottom in case anyone is not familiar with it.

Its toast bud:thumbdown: That has laid down a coating of Piston aluminium on the cylinder and will need the cylinder salvaged if possible and a new piston or a new cylinder and piston. DO NOT just replace the piston, the cylinder must be that smooth, you feel no ridges etc with the pad of your finger - if you can, it will take the piston ring out on the new piston!

 

The reason for failure also needs investigating - common causes are bad/old fuel, leaking crankcase seals, split impulse/inlet manifold and incorrect H screw carb setting.

Thanks for all the replies.

It has always been run with 50:1.

Spud

Thanks for the feedback.

I can just get my the tip of my little finger nail in there and can feel the ridges on the piston.

So the pot has to come off and am sure the cylinder will be scored so let's right that bit off. What do I need to look for in the crankcase that might be causing problems?

Bearing in mind that I am now retired and the saw will only be used domestically, I have seen that there are some 3rd party piston and pot assemblies available for the 50. Are these up to scratch (unfortunate phrase) for the use I am going to put the saw to?

Thanks

David

Remove the muffler and take a look at the piston through the exhaust port - if the piston looks like someone has taken a coarse file to it and left it with bad vertical scoring, the saw has seized, if it is OK then lets look at the issue again!

I managed to get the muffler off after soaking it with WD overnight and have attached some pictures of the piston though the port. There does seem to be some scoring but don't know how bad you judge that to be. It does not look to be acceptable to me.

I am very unfamiliar with 2 strokes. All my experience has been with car engines. When I turn it over with the starter, plug etc removed it seems to latch at TDC. Though just thinking about it maybe that is when the coil lines up with the coil?

Would appreciate your thoughts on this.

Thanks will do that. Came across a U-Tube video on that last night.

I have a Husky 50 which I have had from new. Cut a few trees but mainly used on through & through timber from the mill, so quite light use.

It has always been a good starter until this year. I drained the fuel out (I have read here that that should be done). When refilled (normal lead free) it then ran ok, but not an easy start.

I had to cut up an old fallen oak from the storms and it was having to work quite (had a new chain on it). Then noticed that smoke was coming out of the vents around the starter housing. Left it to cool down and after would not start again unless one of us held the throttle full open. It worked but would not idle. Next day it would not start under any condition.

Put in a new spark plug as I could not see a spark when I spun it over. Then suspected the ignition module so have replaced that. Got a spark but no start. Putting my thumb over the plug hole I can feel compression.

So now I am wondering where I should go next. I would appreciate any advice anyone might have.

Thanks