Hi,
as well as the above checks also suggest to remove the float chamber fuel inlet elbow and float needle and seat and see if you have crud sitting in the elbow or before/over the needle seat and be sure to blow out the fuel lines and shut off valves in the reverse direction of fuel flow with the taps fully open.
Cheers,
Eddie B.

Yes thank you all for the tips. I didnt get to work on the old iron today. It may be the last chance to take the family out in the tinner before things get too cold so we did that today. I dont think the governor was holding it out but good point to check it over and give it a little maintenance. My Cat has a plastic tank off a snowblower, 1/4 and 5/16 fuel hose, a see through Fram inline filter and I rigged a brass 1/4 turn valve. I will check fuel flow at the carb. I did clean the fitting into the bowl, float valve. There shouldn't be anything hiding there but I will check again. Would any of the passages in the bowl give the symptoms I noted? The rest of the carb I went over thr other day. I pulled the metering jet tube and blew it all out, inspected. All looked pretty good.

Here is my setup

i wonder if your fuel line routing could be improved...more horizontal...shorter...more direct and downhill to carb all the way.....mount the shut-off valve horizontal too...

-not saying this is your problem but i think the vertical up and down of the fuel line is potentially troublesome...thinking out loud....

when i setup my D2 and D4 fuel lines with shutoff and inline filter i made them at least horizontal or slight down pitch to the carburetor

i had similar sluggishness in my pony. it turned out to be the spark plugs. the old plugs were not old or carboned or black and the spark looked ok. i got a new set and all was fixed.

Before I removed and cleaned the carb on my 212 Grader it would not run unless the pony tank was full to the brim. I tried a portable tank hanging 18 inches higher than the stock and with that wee bit of extra pressure it ran beautiful. I removrd and cleaned the carb, including all passages and fuel lines and it came around to running great with the normal tank. There is not much gravity in that system for a positive flow. A clean system is a must.

something to remember when checking for spark magnetos make more powerful sparks the harder you spin them thats the idea behind impulse magnetos that sudden drive release make bigger spark.

just becuase a plug works out side the cyl doesnt mean it will work when under cyl compression. a tip is to open the plug gap a couple of thou a bigger gap means a bit bigger spark but only to a certain point.

also check the compression of the pilot using a compression test guage both cyl should be fairly even and within specifed deviation if low rebuild is required.

Mangoman wrote:

Yes thank you all for the tips. I didnt get to work on the old iron today. It may be the last chance to take the family out in the tinner before things get too cold so we did that today. I dont think the governor was holding it out but good point to check it over and give it a little maintenance. My Cat has a plastic tank off a snowblower, 1/4 and 5/16 fuel hose, a see through Fram inline filter and I rigged a brass 1/4 turn valve. I will check fuel flow at the carb. I did clean the fitting into the bowl, float valve. There shouldn't be anything hiding there but I will check again. Would any of the passages in the bowl give the symptoms I noted? The rest of the carb I went over thr other day. I pulled the metering jet tube and blew it all out, inspected. All looked pretty good.

yes the galleries are so fine in carbs they can look clean but be dirty. many small engine workshops now sonic bath carbs to clean them works much better than trying to use fine wire. for a small fee they will do this for you. have you changed the sparkplugs very simple and cost effective no one does proper plug testing anymore let alone have the equipment.
its cheaper to replace when suspect.

Thank you everyone for the pointers. I (re) cleaned my carb. Drilled out the plugs in the bowl and put a small drill bit or torch tip cleaner through anything I could. Blew it all clean with brake clean. Made a new bowl and bowl to throttle gaskets. I have a couple 386 Autolite plugs, mag clearances are set and should put it together this weekend. I will see if I can revise my tank and fuel lines and make sure there is no obstruction. Will keep everyone posted. I'm pretty confident she should run proper.