Ported, Muffler Modded Dolmar Starting Issues

[ChipChomper]

Just ported, deleted base gasket, and MM'd my Dolmar 460. Inlet and exhaust ports were widened side to side but not raised or lowered and intake ports were flowed but not enlarged. Power gains at WOT in wood are great its just been finicky on start up, revving and while idling. It 4-strokes nicely out of the cut and cleans up once in wood but the idle, rev, and starting are being all stupid. In particular I am concerned about how it recently wouldn't start at all after cutting with it for a bit, then setting it aside for 10 minutes while moving wood. Then after getting home it started fine. Saw seems to have unusually unresponsive changes to carb adjustment. Please weigh in on post-modding carb-tuning or whatever you think the problem might be.

 

[Huskvarna hotellgäst]

And you're sure it's not leaking where the base gasket is no longer?

 

[ChipChomper]

I haven't tested it. I haven't got into much pressure testing but certainly should. I'll see if I can find any threads on it. Thanks for the lead!

 

[Huskitoter]

In my very limited experience (two saws), porting made it more difficult to find the sweet spot for carb settings. Unlike many who post running richer after porting, I had to tune a tad leaner on both saws. I think the better air flow disharges more exhaust, making room for more fresh mixture per stroke. Ymmv.

 

[NSEric]

I ported a few Chinese saws.
All of them like a slightly higher idle with the low a hair rich.

 

[ChipChomper]

Ok at a fair amount of fiddling I found the low screw was best set about the same as I had stock. The high screw was set stupid rich to get it to stop bouncing off the limiter to the point that if I opened any more the saw would die upon blipping wot. The idle screw was set pretty rediculously high (chain just moving ever so slightly here and there) to keep it alive, as I'm guessing the lighter components of the small saw couldn't maintain enough inertia to keep it idling with the increased compression. And it seems that a new spark plug and changing fuel mix from 50:1 to 40:1 has helped as well. Thanks for your help in this process!!