394xp rpm issue

[MAngelotti1]

Been working on a 394xp I recently acquired. Compression good new fuel line ,NOS carb ,new carb to intake gasket. I cannot get high rpm above 10,400. Replaced coil same issue. Close H adjustment same issue. No air filter same issue. New plug same issue. Idles fine revs fine but won’t go above 10,400. Any suggestions?

 

[CausticUC]

What are you using to measure rpm?

 

[MAngelotti1]

A tach which on any of my other saws reads as it should.

 

[CausticUC]

Then @huskihl has info for you at: https://************/threads/394xp-low-on-max-rpm-after-port-work.8706/


Hmmm it doesnt like ope ...

 

[MAngelotti1]

Thread won’t open

 

[MAngelotti1]

Throttle is maxing against carb body. I will confirm butterfly but there is no resistance

 

[huskihl]

Throttle is maxing against carb body. I will confirm butterfly but there is no resistance

Check to make sure it opens all the way. That’s usually what it is. Either the cable is stretched out or there is slop in the trigger or in the white piece of plastic that the cable wraps around

 

[huskihl]

Thread won’t open

The owners here don’t like it when you link to other sites. In place of those * above, you can type in AboristSite without and spaces

 

[MAngelotti1]

Just confirmed. The throttle shaft is rotating all the way. Actually pushed it with my finger and still only 10,400

 

[albert]

Pull the muffler look ar piston and cylinder. Check spark screen. Oem coil? Flywheel key?

 

[MAngelotti1]

Changed coil , piston good, will check flywheel

 

[RED-85-Z51]

Were these coils limited?

Sent from my LM-G820 using Tapatalk

 

[MAngelotti1]

Aftermarket by the looks of what was on it. And the second I just ordered aftermarket. If they’re limited It wouldn’t be for 10,400 right? Seems awful low.

 

[MAngelotti1]

Flywheel key is in place and in good shape. No indication on flywheel it moved.

 

[MAngelotti1]

I removed muffler to dual port it and there’s definitely no restriction.

 

[albert]

Ok, so I assume it's too rich. How does it tach at 1 turn out. China parts take trouble shooting to another level.
China coils and carbs??

 

[MAngelotti1]

One carb no’s. China coil. Spec sheet says 3/4 on H. Just put it in wood and no power. Real lazy on throttle.

 

[albert]

So 10.4k H closed and slows down as you open it ?

 

[huskihl]

Aftermarket by the looks of what was on it. And the second I just ordered aftermarket. If they’re limited It wouldn’t be for 10,400 right? Seems awful low.

I haven’t found an aftermarket coil for 394 or 395 that was any good.

 

[huskihl]

One carb no’s. China coil. Spec sheet says 3/4 on H. Just put it in wood and no power. Real lazy on throttle.

Diaphragms in the carburetor might be stiff and holding the lever open and maybe somehow that’s making it rich. Put a carburetor kit in it also