How do I tune this unusual carb?

Nutball

TreeHouser
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Mt. Juliet, TN
I got a new blower, the cheapest good rated one I could find (with the intentions of a few future mods). It's a Poulan, and seems to blow harder than a BG50 or 86.

Anyway in my opinion it runs really hot. It seemed to start loosing a little power after a few minutes of full throttle on the first use. By then I was done, and noticed it seemed very warm, so I let it idle for a minute, shut it off, then measured the cylinder temp a minute or two later. 287F on the side of the cylinder. I hope there's no permanent damage.

I've heard of high performance RC airplane gas engines peaking a high head temp of around 300-320F while normally running in the mid to low 200's. I think I've measured my 2188 up to 240F after a few cuts.

Do you guys think it's running too hot? I'll try to remember to measure the blowers at work tomorrow. Anyway, I'd like to tune it as rich as possible without 4 stroking. The carb looks similar to that of an Echo 265 blower which I thought had no normal needle valves. I've seen where the MS170 has a single needle.

This appears to have one obvious valve. Anyone know whay it's for? The high or low? I've also wondered if there's a weird tuning mechanism on top where the brass is. It appears that brass attaches to the needle in the spray bar valve which is sometimes the high speed needle in small RC glow engines.

How does the plug look? The picture doesn't quite show it, but the bar has a very white powder on it. I might also try cutting out some of the intake filter fins for more airflow.

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If it's only got one needle it would be the low speed .The plug doesn't have enough run time to see anything .When it does it should show a slightly brown color .
 
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Then I bet the brass part is the high speed in disguise. It has a pointer indicator pointing to a variable sized indicator that I just now noticed from the pictures. Looks like it is aimed near max EPA recommended richness. The shape of the brass part is like an inside out Pac man shaped needle (I've seen the normal Pac man needles on a Homelite).

Edit:
Looking at a parts explosion for the Echo 265 blower, I see an anti tamper plug in the brass part (H needle?) And one in the side needle which is labeled High sped needle. I also assumed the side needle would be a low speed since it doesn't much affect emissions, but is needed for a good running tool. Maybe the brass is the low speed. I have seen bad carb designs where the spray bar is made of a high speed needle going into a low speed adjuster. I'll rev it up and turn it to see what happens.

Edit:
The single needle is the high speed. They had it tuned so lean it actually gained significant rpm from richening it. Still runs hot after a bit of tuning and muffler mod, maybe a little cooler. It has significant rpm reduction from taking the narrow tube off, so there appears to be much room for performance increase.

Would 93 octane 100% gas run hotter than 87?
 
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