Husqvarna 450 x-torq, help needed

atpchas

atpchas

AtA
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I'm working on a Husky 450 x-torq for a buddy's buddy, so the history is less than ideal. Basic statement of problem I'm seeing: saw starts (reluctantly) but will not run at anything approaching an idle. Things I've done/checked:
1. Tried several different carbs, no appreciable change.
2. New fuel lines and filter - no change,
3. P/V tested (twice) - tight as a drum.
4. Fresh spark plug
5. Compression is about 140 - not great but certainly should be adequate.
6. Rubber manifold between carb and cylinder is sound, no tears or rubber rot.
7. MityVac plugged into impulse tube shows pressure changes when engine is pulled over.
8. Tried all sorts of variations on needles from approx 1 turn out to 3. Shop manual says start at 2 turns on H & L.
9. No scoring evident through muff or carb ports.

Thanks for any other avenues to pursue before I completely give up on this saw.

P.S. The engineer/designer who thought it would be fun for the carb needle access holes to hide behind the rope handle should be sentenced to eternity trying to make adjustments on such a saw when it requires one hand on throttle to keep it running. AAARRRGH!
 
tomalophicon

tomalophicon

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I'm working on a Husky 450 x-torq for a buddy's buddy, so the history is less than ideal. Basic statement of problem I'm seeing: saw starts (reluctantly) but will not run at anything approaching an idle. Things I've done/checked:
1. Tried several different carbs, no appreciable change.
2. New fuel lines and filter - no change,
3. P/V tested (twice) - tight as a drum.
4. Fresh spark plug
5. Compression is about 140 - not great but certainly should be adequate.
6. Rubber manifold between carb and cylinder is sound, no tears or rubber rot.
7. MityVac plugged into impulse tube shows pressure changes when engine is pulled over.
8. Tried all sorts of variations on needles from approx 1 turn out to 3. Shop manual says start at 2 turns on H & L.
9. No scoring evident through muff or carb ports.

Thanks for any other avenues to pursue before I completely give up on this saw.

P.S. The engineer/designer who thought it would be fun for the carb needle access holes to hide behind the rope handle should be sentenced to eternity trying to make adjustments on such a saw when it requires one hand on throttle to keep it running. AAARRRGH!
Have you checked spark? How about electrical connections and coil air gap? You mention a new plug but maybe spark isn't there or inadequate?

Flywheel timing key?
 
atpchas

atpchas

AtA
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Have you checked spark? How about electrical connections and coil air gap? You mention a new plug but maybe spark isn't there or inadequate?

Flywheel timing key?
Plenty of spark. Electrical connections are sound. Relatively new saw, wire coatings are still very flexible, no age cracks in insulation. Coil gap is usual business card and key is in its slot.
 
Jasent

Jasent

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NorthEastern wa
I’m working on a husky 41 with bad carb. It’s sucking air threw the throttle shaft. Took me forever to find the leak!!!! Would not idle with out choke
 
atpchas

atpchas

AtA
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I’m working on a husky 41 with bad carb. It’s sucking air threw the throttle shaft. Took me forever to find the leak!!!! Would not idle with out choke
Same saw behavior with multiple carbs tends to rule that out.
No, less than 2 weeks old and all my other machines run it happily.
I had a 450 smear the FW key and jump time.
That was a problem (self-inflicted, don't ask) until I replaced the FW.
 
GeorgiaVol

GeorgiaVol

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I have one that is similar. Won't settle the idle. Jumps around a lot. Originally, I found out the wrong needle valve was put in, but even after that it wasn't right. I just plan on replacing the bearing seals. They are old anyway. I'll see if that helps.
 
atpchas

atpchas

AtA
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Those are those strato Zama carbs right?
Those are real finicky in the saws I have tried to fix. I don't like those at all.
Yes, the C1M-EL37B. Problem is I can't get the rpms to a point that I can even begin to tune. The saw wants to race at near cutting speed or die as soon as the revs drop to what I'd guess is 4-5K or so.
 

J D

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What base adjustment are you starting with? I think they should be set at 2 or 3 turns out not the usual 1 to 1½
 
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