576xp non autotune

[Brendan42]

So ill start this off short, and hopefully someone can help me, i got a 2014 576xp non autotune last year, thing bairly looked used besides dinged up muffler, chipped paint and a broken peice of the case to hold the chain brake handle, turns out the cylinder threads for the plug were stripped, found that out tuning it, and the carb was junk, got a new top end and carb during the winter, put it all together and broke it in (tank of gas through it) tuned it slighty rich for the first couple times using it, went great absolutely flawless besides the motor choking out starting it while hot the last time running it, cleaned it up and checked the plug yesterday, grey/white as a ghost(lean as all) clearly was burning up, tried to tune it today and had absolutely no control of the adjustments, checked the high with a tach, read 13,200 and choked out like it ran out of fuel for a split second, topped the tank and tried it in wood, same damn thing, could the crank seals be done, pulled the sides and they slightly look wet but not really, i hope the carb isnt junk already dont wanna spend anouther 130 for one, hope someone can help

 

[Andyshine77]

What does choked out mean?

Sounds like the saw was/is a basket case. You'll need to pressure/vac test the saw to see if there's an air leak. Also these saws have a rev limited coil so the really need to be tuned in the cut under light load. Tuning to say 13,100 should be safe as well, but I really don't know where these saws like to run, I guess something around there.

If the saw is running that lean you're going to want to remove the muffler and have a look at the piston and cylinder for any damage.

 

[Brendan42]

Not wanting to ide/rev up without dieing, and guess ill be looking into a presure/vac tester now, thank you

This has been about my 3rd or 4th saw that ive done a top end on, and a 372 that ive done top to bottom without any problems and this is my first one that acted up on me, presure tester will definitely be getting used on my saws here on out

 

[Andyshine77]

OK.

Pop the muffler off that will tell you if any damage has been done. You can also check the compression.

Sometimes if you don't know exactly how to set up a carb they can give people trouble. This video may help you. Don't run the saw anymore before checking it first, don't want to possibly cause more damage..

 

[Brendan42]

Gonna pop the muffler right after i put the flywheel and cover back on and check it to make sure no damage has been done

I dont think im worrying to much on my tuning skills, I must have backed the low adjuster 2 1/2 turns out without it richening, and started from 1 1/2 turns, never changed pitch, the idle changed from 2,700 to about 2,300 while warming up hencing why i think its the seals along with over reving in my books, the high screw did the same thing as the low, started about 1 1/4 as i do with every saw i have, and adjust from there

 

[Andyshine77]

Gonna pop the muffler right after i put the flywheel and cover back on and check it to make sure no damage has been done

I dont think im worrying to much on my tuning skills, I must have backed the low adjuster 2 1/2 turns out without it richening, and started from 1 1/2 turns, never changed pitch, the idle changed from 2,700 to about 2,300 while warming up hencing why i think its the seals along with over reving in my books, the high screw did the same thing as the low, started about 1 1/4 as i do with every saw i have, and adjust from there

Sounds like you have grasp on basic tuning. If the L had little effect it does sound like you have an air leak somewhere.

If tge top end looks fine you can always start her up and spray WD40 around all the seals and see is it slows down and starts smoking after you spray. This doesn't always find the leak, but it's easy to do.

 

[Brendan42]

Ill check around the seals and see if i find any wet areas, and ill try that out tomorrow when its light out, damn nothern winter

 

[Andyshine77]

Ill check around the seals and see if i find any wet areas, and ill try that out tomorrow when its light out, damn nothern winter

Not really going to see wet areas like you would with a 4 cycle, most air leaks are totally invisible, a little oil does ooze out overtime but very little.[emoji111]

 

[Brendan42]

Yeah, true, pulled the muffler, rings have no scaring, cylinder bore looks like new still

 

[Andyshine77]

Piston skirt? Sounds like she's in good shape.

 

[Deleted member 117362]

H 3 turns, L 1-1/2 . Idle 2700 no load 13,000.

 

[brad ruch]

Here is the part #s for the intake and exhaust block off.i just did a 576.these are cheap and makes the job much easier and quicker.comes with the bolts for the intake plates also.
502 54 11-02
502 52 48-01
I'm betting on a air leak.

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[Brendan42]

So update, got the comp/vac tester and the block off plates, set it all up tested from the plug adapter back the the tester and was good, put it on the saw and heard a leak from around the decomp valve block off or the purge line.

Was wondering if anyone knew the proper torque for the decomp valve, if I remember right i put it about 110-120 inch pounds, i wanna actually build pressure/vacuum and find the actual problem area

 

[Deleted member 117362]

I posted a shop manual. Just download it.

 

[Brendan42]

Sorry for that one haha, I hardly use a manual unless im trying to find an important spec, tourqed the decomp valve and head, and reseated the exhaust block off and built up pressure, dropped .5 psi over 4 minutes, gonna do a vac test next and will keep you guys updated

 

[Brendan42]

Correction.7(.8) bar and dropped .05 bar on presure test, overall dropped .1-.15 bar over 15 minutes, pulled -.4 bar and dropped .1 bar over 2 mins and holding steady at .3 bar, im assuming those numbers sound good to someone with more time doing pressure/vac tests.

The manual only called for .7 bar max drop to .6 over 30 seconds so im way above that, and the vac test it didn’t list and that is all I could pull was -.4 bar

 

[brad ruch]

I doubt the carb is bad.sounds like it's starving fuel.so either impulse line or fuel line.odd it ran good for a tank.

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[Brendan42]

I doubt the carb is bad.sounds like it's starving fuel.so either impulse line or fuel line.odd it ran good for a tank.

Yeah, it ran good through out the break in cycle, tuned in amazing had the top up at 12,500-13,000 and went great altho the few times it struggled starting back up

 

[Brendan42]

To anyone looking into it or still following this thread, yep bad crank seals, just finished installing them half an hour ago, set it 2 on the low and 3 on the high just to see if it would bog and run rich on the low sence it was getting dark out, and yep did just as I expected, ran slightly boggy, 1/4-1/2 turn leaner and test the high end and she will be back in the wood, thanks to everyone that helped along the way

 

[Andyshine77]

To anyone looking into it or still following this thread, yep bad crank seals, just finished installing them half an hour ago, set it 2 on the low and 3 on the high just to see if it would bog and run rich on the low sence it was getting dark out, and yep did just as I expected, ran slightly boggy, 1/4-1/2 turn leaner and test the high end and she will be back in the wood, thanks to everyone that helped along the way

Glad you got it running right!