Dolmar 120 Question

[allg32]

New to the board and have a question on the Dolmar 120's, I have two of these saws, one I use frequently and the other was just a back up. It has been sitting in my garage for probably 4 years. The one I use has gotten ornery and wont hardly start or cut when it is running, so I pulled the other one out to cut with and it will start and run for about 30 seconds then it dies and then wont start for a couple of hours then we get to repeat the process.
Any ideas on where to start looking?  Maybe ignition coil but not sure why it would start then not start

[loggah]

fuel filter,and fuel line.

[Hilltop366]

clean the carb too.

[allg32]

choke was stuck open so it was flooding out quickly, fixed that problem then noticed the set screw was gone from the side of the carb. Not sure how it got there but it was under the carb.

Did a little cleaning up and now she runs like a champ!
Gonna put it to work tomorrow and see how it runs when its cutting.

[allg32]

Got a couple more questions
On the one saw I was using the compression is only about 80 psi, is this normal or low?

I may rebuild it so any ideas on what extras can be done to make it even better.

[sawguy21]

80 is low but parts are getting hard to find. They were well built saws although a little heavy. I would snag a good one.

[AdkStihl]

80psi is crazy low.
I'm surprised it even runs.
I'm guessing there is something wrong with the way you comp tested or something wrong with the gauge.

[allg32]

80 is the one that quit on me, my backup that had been sitting forever has around 100, it cuts OK but starts cutting to the left after I'm about a bar deep into the cut. May flip the bar and see if it goes the other way or I guess it could be my chain needs sharpening.

Both saws are SI's

[stihlsawer]

130 psi or higher is where the saw ought to be, but run it till it quits and pull the cylinder. If the cylinder is scored get an aftermarket cylinder and piston kit. You can still find them on EBAY and elsewhere. If the cylinder is still good, then just get an aftermarket piston kit ($30-40). Either case, I have had good results with Meteor kits. Your 120si is the same saw as my 116si. It just has the larger bore. Hope this helps. Have a blessed day.

Trever

[SawTroll]

80 is the one that quit on me, my backup that had been sitting forever has around 100, it cuts OK but starts cutting to the left after I'm about a bar deep into the cut. May flip the bar and see if it goes the other way or I guess it could be my chain needs sharpening.

Both saws are SI's

Are you sure that your tester is suitable for small two-strokes? 100 also is lower than what chainsaws normally needs to run at all (around 120). Good is 150 or more....

An automotive tester will always read low on a chainsaw, as the attachment isn't right, even if it fits.

[stihlsawer]

Are you sure that your tester is suitable for small two-strokes? 100 also is lower than what chainsaws normally needs to run at all (around 120). Good is 150 or more....

An automotive tester will always read low on a chainsaw, as the attachment isn't right, even if it fits.
[/quote]

+1  The schrader valve needs to be in the end of the hose that screws into the spark plug hole.

[nmurph]

130 psi or higher is where the saw ought to be, but run it till it quits and pull the cylinder. If the cylinder is scored get an aftermarket cylinder and piston kit. You can still find them on EBAY and elsewhere. If the cylinder is still good, then just get an aftermarket piston kit ($30-40). Either case, I have had good results with Meteor kits.
Your 120si is the same saw as my 116si. It just has the larger bore. Hope this helps. Have a blessed day.

Trever

I don't think there is an aftermarket 120 P/C. I searched Ebay and couldn't find one and with the age and limited distribution of that saw it is unlikely that it is economically feasible to produce one. Also, Meteor doesn't make a piston for a 120 unless a 6000 piston will fit.

To the OP, you need a tester with the valve at the foot of the tester (where it screws into the plug hole). With the small combustion chamber size and with no valves to trap the charge, this valve arrangement is needed to give an accurate reading.