Stihl 038 Refurb

[htb]

Would like to see a bit more than that, what tester did you use as some better than others

[Joe Newton]

I had an 038 super on a 20" bar and it was a torquey lump of a saw. An 18" bar would run lovely. It was a dead simple job to replace the piston rings (I bought meteor ones, which are apparently a good make if you don't want to splash out for oem. )

 

Really easy and simple to maintain if you don't mind the extra weight and slightly slower chain speed. 

[Mark Wileman]

1 hour ago, htb said:

Would like to see a bit more than that, what tester did you use as some better than others

One of the cheap silverline ones off E-bay, I left my 550 in the work van or I'd test it against that. 

[spudulike]

That compression is awful, should be 150-170psi if the saw top end is good and suspect you have used a car gauge which is unsuitable for small engines. The comparison is a sound idea but you will need the small plug convertor and it will measure a bit less because of it!

[Mark Wileman]

1 minute ago, spudulike said:

That compression is awful, should be 150-170psi if the saw top end is good and suspect you have used a car gauge which is unsuitable for small engines.

https://www.amazon.co.uk/Silverline-598559-Compression-Testing-5-Piece/dp/B0015NRKFE/ref=sr_1_2?ie=UTF8&qid=1522180760&sr=8-2&keywords=engine+compression+tester

 

I used this ^

[Mark Wileman]

I can't see any scoring on the piston or inside the cylinder, looked from the plug and muffler side. This saw is about 30 years old though!

 

Oh, I did forget to mention, she fires up fine, a bit sluggish when shes not been started for a while and occasionally have to take the air filter off to get her going first time - but that might just be because i'm a pussy and can't drop start a 10 kilo saw!

[spudulike]

Easiest thing to do is to lift the saw with the starter handle and see how quickly it drops and if it holds on each compression stroke or just falls.

The comparison with another good working saw on your compression gauge is a good idea.

[Mark Wileman]

7 hours ago, spudulike said:

Easiest thing to do is to lift the saw with the starter handle and see how quickly it drops and if it holds on each compression stroke or just falls.

The comparison with another good working saw on your compression gauge is a good idea.

It's pretty good, one slow pull to build up the compression then it takes about 10-15 seconds to fully uncoil, tightening on each stroke.

[Mark Wileman]

I wasn't sure how reliable that method would be as the saw is 6.6k without oil and fuel.

[bmp01]

Dunno if this helps. .. I've never tried this starter cord compression test.

 

My 028 has 155psi after 10 pulls, using an old fashioned "pencil" compression tester (looks like the extending tyre pressure testers but it has a one way valve in there and is rated for cylinder pressures). Anyway, no long tube prior to the  one way valve which should avoid low readings. 

 

Drop test - the 028 weighs 7 kg with bar and chain and takes appox 20 seconds to get to the end of the starter cord, 3 or 4 revoulutions (each compression event is very obvious). In hind I might have done this wrong? I held the saw in the air and dropped it while holding the cord. It slowed down more and more with each subsequent revolution so by the final compression event it nearly stopped. Didnt attempt to build up any pressure at start... 

 

20 seconds feels like forever by the way,  definitely need to do the  "1 Mississippi, 2 Mississippi,.....etc" thing  

 

And a bit disappointed with only 155 psi, this saw has had new Caber rings and has been squished to 20 thou. But then again it is an old saw design and the combustion chamber is probably a bit big compared to modern saws... runs fine, good torque.