MS440 Won't Idle

[francisjohn]

Before someone says "have you tried the idle screw" yes, I am familiar with idle screws.
Before someone says "test for air leaks" that is impossible if I can't idle it, and no, I'm not buying a $150 smoke machine and more money for a 12v battery to run it.

MS440 w/ NIBBI PE19 Engine runs fantastic, but will not idle, here is what I've experienced
Main jet : 95
Pilot jet : 32

-I tried a different carb (PZ19) and had the same issue.
-I messed with the pilot and main jet, including the needle (even though the issue is at idle)
-When disengaging the clutch it idles for 2 secs and die. If I turn the idle screw all the way in, it will idle for 2 seconds at a higher speed and die.
-Fuel screw isn't responsive to richening or leaning.
-I tried to disengage the clutch, gave it light throttle, it died. I cannot blip the throttle to keep it alive.
-Idle screw works correctly as it pushes up the slide, including the throttle cable (spring and slide) are returning properly.
-The bike doesn't run away, or run on choke. If engaging clutch with no throttle, it will stall out as normal. If the clutch plate was too tight, the bike would move forward very slowly.

I noticed after WOT or up hill runs, the engine sky rockets RPMs and dies What's strange is it acts EXACTLY as if you were to idle the bike, shut the petcock off, and once it runs out of gas it becomes lean which raises the RPMs dramatically and die. I feel this is important information, and don't know if these symptoms can help re-direct my problem.

I appreciate all help,

 

[Chainlube]

How much of an angle do you have on the engine? Too much angle will limit the fuel in the bowl. I didn't draw all the parts inside just the fuel level.

 

[GW's Motorized]

If you crack the throttle open will it stay running?

 

[francisjohn]

How much of an angle do you have on the engine? Too much angle will limit the fuel in the bowl. I didn't draw all the parts inside just the fuel level.

Thanks for the response.

Initially, the carb was leaning backwards instead of level, or leaning into the engine. I solved this by shortening the intake so that the carb rests on the clutch cover. Prior, the carb was dangling in outer space.

The engine does idle after going from a #32 to #38 pilot jet. However, the idle is still up and down.

I don't know if this is normal in chainsaws, unlike china dolls which tend to have a pretty steady idle.

I can't help but wonder if the fuel line is the issue. It's the 4L tank and the petcock is at a 90 degree angle. The line normally rests right where the hose clamp is for the filter, but due to vibration it does tend to move up. I have adjusted the fuel line so it's in a better position and tried to idle, and the idle is still kinda all over the place.

I did switch out my clutch assembly to see if it was causing any problems. Interestingly enough, the spring that came with the engine I built the 440 on is much shorter and weaker than the typical spring that comes with the bottom ends. I don't think that is the direct link to all this, I think it's many factors.

If you crack the throttle open will it stay running?

It will now after going from a #32 to #38 pilot jet. Before it would just die, it will keep going if I crack the throttle. The one that came with my engine is shorter and weaker. It would make sense if that caused problems. I think there are many factors going on here.

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[GW's Motorized]

Now that it will idle have you checked for air leaks

 

[francisjohn]

Now that it will idle have you checked for air leaks

That will be on the schedule very soon. I hope to god it isn't the base gasket and an even deck surface when I decked the case. I did fix the fuel line routing so that it slopes down and remains even on the 90 degree bend