Sachs Dolmar 100

[Ricko]

Hi,

Having got one of my Dolmar 100 saws running today I thought I'd try getting another one to run.

It has 135psi compression and the plug is sparking. I stripped the carb, cleaned it and put fresh fuel in the tank. When I put a bit of fuel down the plug hole it doesn't seem to fire, it just occasionally puffs out a bit of smoke.

Any thoughts/advice welcome.

Cheers

[spudulike]

135psi is very low, what compression gauge are you using? 150+ is more typical on small saws.

[Ricko]

20 minutes ago, spudulike said:

135psi is very low, what compression gauge are you using? 150+ is more typical on small saws.

I'm using a Clarke one, I had a similar reading on the other Dolmar 100 which I got running.

[spudulike]

The compression gauge is probably for car engines so isn't a valid reading. If the compression is OK, Just check the spark, if that is good then it will be typically fuel filter, fuel line or carb issues. You could try the carb off the one that runs!

[Ricko]

1 hour ago, spudulike said:

The compression gauge is probably for car engines so isn't a valid reading. If the compression is OK, Just check the spark, if that is good then it will be typically fuel filter, fuel line or carb issues. You could try the carb off the one that runs!

Now that's an idea!

Tomorrow's project!!

[Ricko]

Swapped carbs over, no joy.

Then I couldn't get the original one to run properly when I swapped them back again, arghhh!!

[bmp01]

14 minutes ago, Ricko said:

Swapped carbs over, no joy.

Then I couldn't get the original one to run properly when I swapped them back again, arghhh!!

Maybe you crudded up your 'good' carb. Old fuel, dirt - filter or fuel line fault in the non runner saw introduced crap into good carb ?

 

Back at the start,  you said you can't get the non runner to run on a bit of fuel down the spark plug hole, if that's case I'd focus on that first.  Fresh fuel,  strong spark, decent pull - it ought to run how ever briefly. That's assuming decent compression.  For comparison, what compression did you get on your running saw with that same compression gauge?

 

You can go one step simpler and use easy start spray if you have some.

You can heat the spark plug out of the saw,  it might help marginal mixture.

Go with a new plug anyway, quick/cheap.

Check the spark is a decent one, can it jump a 4-5 mm gap ?

Has the flywheel spun on the crank giving wrong spark timing ?

 

With the running saw you need to visit the carb and fuel system for a general overhaul by the sounds of it. 

HTH.