Couple issues with an SV2AE older mantis tiller. Mantis 2 cycle tiller stalls when at high speed. Attempted to adjust Walbro carburetor using instructions on Walbro website (and here). When I adjust the hi speed needle it has no effect. I can close it all the way and the tiller still runs. Also has cracked Insulator between carb and engine which I understand could cause a vacuum leak. Trying to determine if both need to be replaced or if the cracked insulator is causig the hi needle not to work. I don't want to buy both parts if both are not needed.

Hi Everyone, I've noticed a lot of carb adjustment threads here, but I'm having no luck. I hope ya'll can help me out. I have a Poulon Pro 4218AVX. My chainsaw started acting as if it was out of fuel. It would idle, but going full throttle to cut a tree down it would bog down after 30 seconds and then die. I noticed the in tank fuel filter had seperatred from the gas line. I ended up removing the engine from the case to get access to the fuel line. I ran two new fuel lines (supply and return) to the tank and installed a new fuel filter. Cleaned and reinstalled everything. I also installed a new spark plug and air filter. So I attempted to start it. It would idle ok, but anymore than half throttle would bog down and die. Using the primer bulb, fuel is getting into the carb and flowing through the return line. So I bought the carb adjustment tool. Following the directions somewhere else, I backed the Idle and High screws out till they were barely seated. Half turn on the idle till it would start. I screwed the idle all the way in and it never even tried to catch. I even removed the spark plug and grounded it to the head to see if there was spark. Then I found the directions here. Screwed both idle and high in till lightly seated, back out 1 1/2 turns on the idle, 2 1/2 turns on the high. I've messed with that idle screw screwing out 1/4 turn each time for about 15 minues. I'm tired from cranking that dang chainsaw getting nothing. What am I missing? I'll apologize now if this was covered somewhere else but I'm out of ideas. Thanks, Tim