ECHO PB 265L Compression Check

[shacky]

My small backpack leaf blower wasn't running well. I didn't have time to go through carb so I dropped it off at local shop. They told me it's not worth fixing - low compression showing scored cylinders.

I checked compression myself to make sure. I get ~89. Added few drops of 2-cycle oil and got same reading.

I'm use to seeing 100 or higher but with these tiny 2-cycle motors is th is really low?

Thanks!

 

[bertsmobile1]

Two strokes have 2 compressions.
1) Primary or crankcase compression
2) secondary or cylinder compression

Both have to be good
as does the seals around the crankshaft, cylinder base gasket.
At current labour cost, any one of them will render it an uneconomic repair for a big workshop.

Two strokes are really compression sensitive as little as 1 lb/in can be enough to to go form works like a gem, to almost impossible to start.

Secondly because the combustion chamber is so small, tiny variations in the tester itself can give you false readings.
I fell into that trap when I first started.
My compression tester was a very good one but I had to make a dozen different ends to match the spark plugs position in the chamber.
One thread too far into or out of the combustion chamber can make a massive difference.

Then you get weird things like one that will start & run at 65 psi then the next won't even cough at 90 psi.

This is why we use leak down tests and vacuum/ pressure testing of the crankcase rather than a strait compression test which is fairly useless.

Pull off the muffler to check the piston & bore.
Any scratches that bridge the bore or marks in the cylinder that a probe will catch on will render the engine junk, as will gaps in the plating.

Echo are good and worth the effort of repairing, but not the labour costs.
The local mower shop send customers to me that need hand held engine rebuilds because he charges $ 90 / hr on actual time spent & I charge $ 60 / hr scheduled repair times.

IT can take better than 1 hour just to dissasemble and clean a lot of small hand helds if you have to open up the cases.
A repair kit is around $ 100 and down here no one will just replace rings because if something else breaks, it is deem the fault of the repairer & has to be repaired, no labour cost.
This means that every opened crank case gets new rings, big & little ends , seals & gaskets

 

[shacky]

I don't have a leak down tester. What about the reading NOT changing with additions of few drops of oil? Does that bode well in general?

I'm suspicious of this shop as they falsely told me my honda mower needed piston and rings several years ago. New owners so I thought I didn't have to worry about that happening again.

But I just am suspicious that they did nothing and just said it's toast.

 

[bertsmobile1]

Customer brings in a hand held that won't start.
1 Put an inline spark tester on the plug and a squirt of starter fluid down the throat.
Pull pull pull.
Nothing happens, pull the muffler off & try again
Nothing happens again plug muffler & carb then pressure test cylinder & crankcases.
Usually one will fail and in 1/2 hour engine is declaired uneconomic repair.

Or I can buggerize around for 2 or 3 hours which the owner will not want to pay for ($ 180 ) and then tell the customer the gear is buggered so you will have to buy a new one and pay me more than the cost of a new one for telling you yours is toast.

 

[angellonewolf]

i have on an old strimmer witch the engine will be close with yours

i found this out from an old grounds man if he had a old unit lying around that would not start due to comprssion

is to remove the head and the whole chamber and clean/emery cloth with fine grit finshing with wet and dry when doing the sanding go around and around the chamber as to keep the shape sanding up and down the bore will make it usless keep it going round and round

do this untill you remove most of the scores in the bore at lease reduce them down a fair bit

go to a local engine shop and buy 2 new rings generic ones or just new original ones if the price is right

make some new gaskets out of cardboard or better gasket paper and refit use a drop of 2 stroke in the bore so when you try to start it the first time it does not make more scraches but this will make it harder to start but will make the fix last longer

its is a very time comsuming thing to do only do this if money demands it eg you just want it to last for while when saving up for a new unit as the fix will not last forever but is doable for a few pounds mine total cost £15 (12 for the rings and £3 for the emery paper) i used it for one year after this and then give it away once i had a new to me unit and did honisty say it may not last years but said its free so you have not lost much lol

please know this is for infomation only and any problem arising from doing this is up to you but it has worked for 2 mechines up to date on small engine stimmers and chain saw

it depends on how you value your time and how quick to need to be up and running again i only done it mostly to see if it can be done

and the unit i did give away was still working 6 months later after that but this will depend on how bad the scoring and other factors like how well the sanding went