550xp high idle problem

[Thebigm]

Hi all, first post and I've searched to see if I could find anything to help on here but to no avail!

 

I have a year old 550xp, worked great until this month.

Chain kept spinning at idle so replaced the needle bearing twice and now just replaced to clutch to see if it was that. The bearing fixed it first time round, then I got something caught in the clutch and sprocket so had to take it apart to get it out. Then again the chain started spinning at idle, so replaced the clutch and bearing again.

 

Still spinning at idle, so I had it plugged in to see if it needed resetting (as I don't have access to lumps of wood), they reset it and ran diagnostics to see what was up - nothing showed up apparently.

 

What else could it possibly be? I'm guessing the carb is dead but at labour prices and cost of part I might aswell get a new saw which I'd rather not!

 

Also the saw is just out of warranty typically.

 

Any help would be great.

Cheers.

[felixthelogchopper]

When you say high idle, is the engine actually running faster than it should be? If so, I would suspect a possible air leak. Have a look at the plug to check its colour.

[Stubby]

When you say high idle, is the engine actually running faster than it should be? If so, I would suspect a possible air leak. Have a look at the plug to check its colour.

 

My thoughts also .

[Thebigm]

Yeah, seems to be in idle and full revs. I'll check once I'm home. Very basic question but what's the fix for an air leak?

 

Not sure if it's related either but there was some carbon rattling around the clutch area and exhaust area..?

 

Cheers.

[felixthelogchopper]

Yeah, seems to be in idle and full revs. I'll check once I'm home. Very basic question but what's the fix for an air leak?

 

Not sure if it's related either but there was some carbon rattling around the clutch area and exhaust area..?

 

Cheers.

 

First you would need to pressure and vacuum test your saw. Assuming you found you had a leak, you would then need to find the leak which could be from a variety of places such as crank seals, inlet manifolds etc. It's not a diy job, I'm afraid.

[adw]

You first need to put a tacho on the engine to see if the idle is too fast and causing the problem, max idle for auto tune is 20750, if the engine idle is correct, then it is a clutch/clutch bearing/ sprocket or oil pump gear issue, if the idle is too high check the throttle cable is allowing the throttle shaft to go right back, failing that then yes it could be an air leak, cylinder base gasket leaking, crank seals leaking, or transfer port cover plates loose.

[openspaceman]

You first need to put a tacho on the engine to see if the idle is too fast and causing the problem, max idle for auto tune is 20750, if the engine idle is correct, then it is a clutch/clutch bearing/ sprocket or oil pump gear issue, if the idle is too high check the throttle cable is allowing the throttle shaft to go right back, failing that then yes it could be an air leak, cylinder base gasket leaking, crank seals leaking, or transfer port cover plates loose.

 

Perhaps some terms need a bit of definition here.

 

I refer to hi idle as full throttle no load with a chainsaw and the onset of four stroking, similar to max governed revs on a diesel. Idle is synonymous with tickover for me.

 

Tickover is normally around 2750 rpm but high idle can be 11000-14000 depending on the saw but I get uncomfortable if any of mine go over 13500.

[spudulike]

You first need to put a tacho on the engine to see if the idle is too fast and causing the problem, max idle for auto tune is 20750, if the engine idle is correct, then it is a clutch/clutch bearing/ sprocket or oil pump gear issue, if the idle is too high check the throttle cable is allowing the throttle shaft to go right back, failing that then yes it could be an air leak, cylinder base gasket leaking, crank seals leaking, or transfer port cover plates loose.

 

I think you added a spare "0" there Andrew:blushing: think it should be 2750rpm!

 

Did the dealer do the throttle check when he had the diagnostics on? You just start it, and leave the throttle closed and then open and make sure the autotune sees it OK.

 

Small air leaks will adjusted for with the autotune - it is pretty good like that as it makes the engine survive but will cause some running issues.

[adw]

Sorry got a 0 in the wrong place, idle to me is the tick over, max rpm is full throttle.

[AllyH]

If it's a year old you should have another years warranty left on it if you bought it new from a dealer

 

 

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