Compression testing with a decompression button

[Ricko]

I know a compression test on a two stroke can reveal only limited info but I assume it's a starting point with regard to piston/ring/cylinder condition.

I have a few Makita DPC 6400 lying round (forgive me, I know they're not chainsaws!).

Do I press the blue button IN or pull it OUT to attempt a compression test?

I'm going to attempt to build a good one from the pile and want to select a goodish one to start with.

Comments much appreciated.

[openspaceman]

I know a compression test on a two stroke can reveal only limited info but I assume it's a starting point with regard to piston/ring/cylinder condition.

I have a few Makita DPC 6400 lying round (forgive me, I know they're not chainsaws!).

Do I press the blue button IN or pull it OUT to attempt a compression test?

I'm going to attempt to build a good one from the pile and want to select a goodish one to start with.

Comments much appreciated.

 

The button should be out for full pressure, throttle half open pull it a few times to reach max pressure.

[Ricko]

Thanks for that, what's the procedure for starting an engine with a decompression button, forgive my ignorance but none of my other items have one. Cheers

[adw]

Button in to start, most deco valves will pop out once the engine has fired, press in again to start.

[Daniël Bos]

Thanks for that, what's the procedure for starting an engine with a decompression button, forgive my ignorance but none of my other items have one. Cheers

 

pretend it doesn't exist normally works best.

never use it:thumbup1:

[adw]

Deco valves are there to protect the machines components ( cord, handle pawls etc ) as well as your elbow.

[Daniël Bos]

Deco valves are there to protect the machines components ( cord, handle pawls etc ) as well as your elbow.

 

Mechanical sympathy does these things better, and more...

[Pete Mctree]

pretend it doesn't exist normally works best.

 

never use it:thumbup1:

 

 

Try that on a bigger saw & all you will do is damage it & yourself. We laugh @ work & call it the tart start, but why ruin a machine & your elbows?

[Daniël Bos]

Try that on a bigger saw & all you will do is damage it & yourself. We laugh @ work & call it the tart start, but why ruin a machine & your elbows?

 

None of my smaller saws have one (my 50cc dollies might? dunno tbh) but the husky 372, ms660 (with big bore P+C!) and ms880 all start better without the decomp?

I've never used them, never broken a starter (had a cord snap once or twice on aging saws) never had any elbow issues?

Starting a saw isn't really something you do that often, and the bigger the saw, the longer the cuts and thus less starting?

 

Maybe when I'm really old I'll regret this, but I think not.

[Pete Mctree]

None of my smaller saws have one (my 50cc dollies might? dunno tbh) but the husky 372, ms660 (with big bore P+C!) and ms880 all start better without the decomp?

 

I've never used them, never broken a starter (had a cord snap once or twice on aging saws) never had any elbow issues?

 

Starting a saw isn't really something you do that often, and the bigger the saw, the longer the cuts and thus less starting?

 

 

 

Maybe when I'm really old I'll regret this, but I think not.

 

 

It is only in the last couple of years I have began to think this way & only for bigger saws - 390 660 084 etc must be getting softer as I get older