DOLMAR/MAKITA The Official Sachs Dolmar Dolmar Makita Dolmar Chainsaws Thread

[Mycamaro_68]

Those are good ideas! However, I just tested them both, and they passed. Both the fuel line held pressure, and the tank vented vac properly.

Back to the drawing board on this dolmar...

Is the spark plug wet or dry after it dies?

Is it possible that it has spark at slow cranking speed but looses it at higher rpm? Maybe rig up a drill to spin the flywheel and check spark?

 

[eric4]

Is the spark plug wet or dry after it dies?

Is it possible that it has spark at slow cranking speed but looses it at higher rpm? Maybe rig up a drill to spin the flywheel and check spark?

Looks like it was the coil. I swapped it for a white/silver one I had, and it fired right up! Are coils specific to flywheels on these saws? Is there a model/color of coil that performs best?

Cheers!

 

[eric4]

Looks like it was the coil. I swapped it for a white/silver one I had, and it fired right up! Are coils specific to flywheels on these saws? Is there a model/color of coil that performs best?

Cheers!

Turns out I was wrong! Hah

I assumed it was fixed, since it fired up, idled, and revved for 15 seconds or so, but it was too early in the morning to test.

Brought the saw out again, and it seems to be doing the same problem. Barely starts, and dies with any throttle action. Might throw on a replacement working carb, to see if it was the coil + carb...

 

[Wilhelm]

Did You change the spark plug?

 

[FergusonTO35]

I'm having a heck of a time getting my 5100s running... It fires on choke, and on run (high idle) the saw starts and immediately dies. This makes me reckon it's fuel, or an air leak. So I rebuilt the carb, and tested it on my other 5100, where it was running fine. Then I do a pressure test which it seems to have passed, and the saw still does the same thing. I even made sure to turn the crank while pressure testing, to see if there was a leak while rotating.

If anyone has any ideas, I'm all ears.

Will it run on half choke? Or at WOT with the choke off?

 

[eric4]

Did You change the spark plug?

Tried a new spark plug and have the same results.

Will it run on half choke? Or at WOT with the choke off?

It pops and sometimes idles on full choke. When I bring it to half choke/WOT it takes off and dies. Sometimes it hangs onto idle, but any amount of throttle and it falls on it's face.

Edit: Just tried again with a known working carb, and it gave the same issues... Seems like it's an air leak that doesn't reveal itself in normal testing.

I'm running a leak test by pressurizing the spark plug hole, and blocking off the exhaust, and the intake between the carb and intake boot.

 

[FederalQ]

Wow, frustrating. Try a different fuel filter.

 

[eric4]

Wow, frustrating. Try a different fuel filter.

Replaced the fuel filter again, with a different style. This time the saw ran, idled, and revved. I went to start to tune the saw, but still seem to think there's a problem.

At full throttle, the saw absolutely screams. I didn't bring out the tach, but it had to have been near the limit. So I keep backing out the high jet, and can't seem to get any four-stroking at full throttle even five turns out. The exhaust started to smoke so I cut the saw off. Pulled the muffler and have a tiny scratch now, on my brand new piston. Fun stuff! hah

Seems like some progress has been made, but still a bit stumped. An air leak is probable.