Is it me?

[Fish]

After enduring this years onslaught of "tech" schools, I have
listened to endless drivel about how a compression gauge is
a neccessary tool for the 2 cycle tech. I have one, but never
have even been tempted to use it! It is kind of useless to me
and my approach to repair. I must be missing something.
I worked on a Shindaiwa trimmer once that ran , but poorly.
The compression was not that great, so I removed the muffler.
One ring was worn into 2 pieces, and after disassembly, the
other ring was worn paper thin on one side. Putting a new pair
of rings and a new gasket, the trimmer ran like new again.
It was actually an old Green Machine which was a Shindaiwa
T-25. But back to the topic, I have never had the occaision to
waste any time screwing in a compression gauge to tell me
what was fairly obvious. In a high performance/racing scenario
it may be helpful, but in general repair, it is a useless tool, like a
coil tester.

 

[JimL]

Never use one. Got one but don't use it in 2 cycle.

 

[Fish]

That was quick! Do you use one on small engines[4 cycle]?

 

[dbabcock]

Is this another one of your jokes, Fish? Wondering why a compression gauge isn't particularly useful on single cylinder two stroke engines? I'm speechless.

 

[stihltech]

guage

Never on a 2 cycle. Sometimes on a 4 stroke, but if it is feels down, it is just as easy to pull the head on a small engine. You are probably going to replace an interior component anyways.
Stihl says you will want a compressio and leak down gauge for the four stroke, but I feel the same way, look for the worn or broken component.
Always on a car. Much more work and expense to get to the worn parts.

 

[glens]

I agree with Doug.  This might be a joke.

Be that as it may:  Not being a professional engine-repairer, I only ever use mine (which may or may not provide accurate absolute readings - I don't care, as long as it's consistent at any given time) to check for cylinder balance in multis or whether the rings or valves are at fault in a 4-stroke.

Glen

 

[Tony Snyder]

I agree Fish compresion gauges and coil tester I have but never use.

What I need is x-ray vision.

 

[Fish]

Doug speechless?
I just never have even thought of using one. All of the "official"
sources swear by them, but I see no need. That also goes for
4 cycle SMALL engines.

 

[bwalker]

The are not of much use for small engines IMO. People use them on mx bilkes to determin when to change rings, but this is flawed as bikes have service limit that is surpassed why before comp drops. For someone like Fish who tinkers with other people equipment every day they are usless. Basicaly I have one for curiosity purposes only.

 

[tree monkey]

i only use mine to prove to the customer that i'm right. i get some funny looks when i pull on the rope and say it's shot

 

[dbabcock]

Sometimes I blow into my compression gauge and see if I can get the needle to move. Haven't been able to do this yet. Sometimes I sit in front of my refrigerator and try to open the door quickly enough to catch the light before it turns on. Haven't been able to do this yet.

 

[bwalker]

Doug, ever try to open a microwave fast enought to get a tan?

 

[tony marks]

yep i got one to play with . checked every thing i had at the time.my old partner 5000 tested at 110. its still as fast as any of my saws of that size in hardwood. think it does need a carb kit tho.my opinion a good hardwood is the best compression tester.

 

[Tony Snyder]

Don't some 2 cycles have some designed in leakdown
that occures at cranking speeds but becomes ineffective at running speed, sort of a built in compression relief?

I sold Partners years ago. Seems like remember reading about that pertaining to Partners.

 

[Fish]

Pioneers had the "Easy Arc" auto compression release, which
fooled many mechanics.

 

[stihltech]

tester

Experience may be the best compression tester.

 

[Whistler]

So if a guy walks into a saw shop , see's a used one that catches his eye , would it be a good rule-of-thumb to pick it up by the starter handle to see how it drops or doesn't this 'theory' hold up here ?

 

[stihltech]

test

Good place to start.