Husky 550 Mk2 running problems

[Andrew L]

Hi,

Scratching my head at this one.

Just over a year old 550 Mk 2.

Starts and idles fine and throttle picks up but chain will not spin, as if the chain brake is on.  

Removed bar and chain, and side casing off still happening.  Grease point at clutch regularly greased, not done hundreds of hours.

Unable to turn clutch/sprocket housing manually,,,

Could it be the oil pump has seized?  

Thank you

Andrew

[pleasant]

Crank/drum bearing seized

[Andrew L]

Thank you.

So definitely that and not the oil pump?

If so, is it a dealer workshop job to swap seized bearing for new?

 

Cheers

Andrew

[adw]

I have also seen these melt the oil pump drive gear, this then welds it to the pump body, it can happen if the clutch comes loose on the saw over run, the drum moves out and disengages from the pump gear, when the saw accelerates again the clutch and drum wind back on the crank, unfortunately the drum is now sitting on top of the gear forcing it into the pump body. Not a dealer job, just remove the clutch and pull drum and gear off crank to assess what has happened.

[pleasant]

1 hour ago, adw said:

I have also seen these melt the oil pump drive gear, this then welds it to the pump body, it can happen if the clutch comes loose on the saw over run, the drum moves out and disengages from the pump gear, when the saw accelerates again the clutch and drum wind back on the crank, unfortunately the drum is now sitting on top of the gear forcing it into the pump body. Not a dealer job, just remove the clutch and pull drum and gear off crank to assess what has happened.

Yes.....all working fine whislt its gradually failing in use, then once saw is stopped the soft plastic hardens up and seizes the drum and clutch mechanism so next time you go to use it, its seized

Edited May 7, 2023 by pleasant

[spudulike]

The last thing is possibly the bar nose sprocket could be seized up. Just a case of stripping the parts down and finding the dodgy part.

[Andrew L]

Thanks all, (spudulike) the chain/bar/ side casing are all off and the clutch still cannot spin the drum/sprocket. The melted oil pump drive gear sounds most likely since I have been greasing the crank bearings and the usage is not huge on this saw.  Will delve deeper and let you know,,,

A

[spudulike]

Just remember the clutch spins of clockwise as it has a left hand thread. It sounds like the most probable cause. 

[pleasant]

1 hour ago, Andrew L said:

Thanks all, (spudulike) the chain/bar/ side casing are all off and the clutch still cannot spin the drum/sprocket. The melted oil pump drive gear sounds most likely since I have been greasing the crank bearings and the usage is not huge on this saw.  Will delve deeper and let you know,,,

A

Yes..let us know how you get on.

[Andrew L]

It was the oil pump assembly, this plastic plug thingy was welded on, once off crank turned as normal.  replacement bits ordered, thankfully only £20 or so.  Design fault??  That drive sprocket is the original from new.  Not exactly worn out??