Tell me about the dolmar 123

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Jwaldner

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All the other saws are running good so I had to play with this one. My brother bought it years ago but its seen very little use since then. It was apparently worked through when he bought it.

It's got a 20 hard nose inch bar, I put on a new carlton full chisel blade and went to try it in some big popular. Starts and runs fine but it had no torque. Yet it sounded about right.

I do not have a compression tester that will work on small engines. Just an automotive one.

I found that the carb screws were only 3/4 turn or less from lightly seated. I put them both to 1.5 turns out and went from there, both hi and low are within 1/4 turn from 1.5, I believe in opposite directions now. It has way more power now. But if you push it hard will wants to stall in bigger stuff.

The only thing I have to compare it to as far as a big saw is a dolmar 6100 also with a 20 inch bar, carlton full chissel with the small bumper in front of the raker, which the chain on the 123 do not have. The chain on the 6100 seems less aggressive. Seems. I was alone so no stopwatch.


The 6100 cannot be stopped. Crazy amounts of torque with a 20 buried. The 123 is a bigger saw but seems if you push it it wants to stall.

Maybe it's the chain I could try swapping them. Or have someone time cuts cause I know the smoothness of the new dolmars is deceiving.

Or my carb settings of 1.5 turns out and tune from there are slightly off. It just seems it's missing some power. I'd sleep better at night if I could get it to where I think it should be.


These things apparently have a governed carb. where does this play into the equation?

Also I assume the hard nose bar is costing me a little power. How much?
 
70cc ish, strong saw if it is in good operating condition. Should not be a contest with the 6100, hard tip bar or not.
 
We had them in 20 inch popular today. They were tied. I could try retuning the carb if someone can give me definate numbers on where to start, as in turns out.

On paper the 123 has .1 more kw than the 6100. Pretty sure the 6100 has more rpm
 
I don’t think there’s any difference between an automotive compression tester and a small engine one. Pressure is pressure and automotive and small engines have comparable compression pressure.
 
Well according to my harbor freight compression tester none of my small engines should run. And they all do

The saw does not pull over easy so I assume compression is substantial
 
The difference in compression testers for automotive and small two strokes is in the Schrader valve makeup and the position it is located, must be at the very tip that screws into the cylinder head. This is due to the very small volume of air a chainsaw cylinder can move into the comp tester per stroke . A google search will give one plenty of reading on this subject.
 
so does anyone have a better idea on where to start with carb settings or do I just leave it as is?
 
Each saw will tune in a bit differently and can only be set at a safe rate without tuning the carb in the cut. Fuel mix and quality of the gas, carb condition, atmospheric conditions, amount of wear on the engine, compression and many other small factors all play a part in the tuning of each saw. To pick a actual setting for a random saw would be like sticking your neck in a hangmans noose.
 

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