broken fin on flywheel

rlyddane · 22nd May 2011, 12:31 PM

Hello all,
I have a Stihl MS290 that I bought used. When I got it, I fueled it up, checked everything, and started it. It started fine, eccelerated fine, idled fine. I started cutting down a 12 in" tree and noticed no oil on the bar. Decided to tear it down, and when I got to the flywheel, I noticed 1 broken fin. I had read that 1 broken fin is not critical, but if your concerned about balance, you could break off the opposite fin. Could that reduce the cooling effect that it was meant for? Since I do not want to nor can I afford to start buying parts that may not be 100% necessary, can I get away with 1 broken fin temporarily, and buy a new flywheel later? Or should I bite the bullet and get it now. Also found oil pump broken, so I am ordering a new one of those. By the time I get all done, I am wondering if it would have been cheaper to buy a new saw in the first place. Please let me know your thoughts, Thanks....................Rich

Eric Frei · 22nd May 2011, 03:51 PM

I reckon you'd pick up a 2nd hand one with all fins dirt cheap.

Try this guy, he's a sponsor here.

https://apse.mybigcommerce.com/

APSE · 22nd May 2011, 04:20 PM

A Broken fin on the flywheel causes serious imbalance at the higher RPM range, and reduces the cooling efficiency. If you remove the opposing fin for rough balance, the result is a larger reduction in cooling. If the flywheel had 20 fins and you have removed two of them, you have reduced cooling by 10%, and balance is still a way's off. The balance is important to crankshaft seal and bearing life. If the bottom end is compromised, the top end will be next and the engine is likely to become no longer worth repair.
It is like likely we have a good used one, please send us a PM if you are interested. Otherwise the life of this saw in "as is" condition is very limited, and there is also a possibility of schrapnel (as in grenade)at higher RPM ranges...
Brian and Tina

22nd May 2011, 12:31 PM	#1
rlyddane I'm new here so be nice Join Date: May 2011 Location: Mead, OK Posts: 2	broken fin on flywheel Hello all, I have a Stihl MS290 that I bought used. When I got it, I fueled it up, checked everything, and started it. It started fine, eccelerated fine, idled fine. I started cutting down a 12 in" tree and noticed no oil on the bar. Decided to tear it down, and when I got to the flywheel, I noticed 1 broken fin. I had read that 1 broken fin is not critical, but if your concerned about balance, you could break off the opposite fin. Could that reduce the cooling effect that it was meant for? Since I do not want to nor can I afford to start buying parts that may not be 100% necessary, can I get away with 1 broken fin temporarily, and buy a new flywheel later? Or should I bite the bullet and get it now. Also found oil pump broken, so I am ordering a new one of those. By the time I get all done, I am wondering if it would have been cheaper to buy a new saw in the first place. Please let me know your thoughts, Thanks....................Rich

22nd May 2011, 03:51 PM	#2
Eric Frei Admin - Owner Palm & Tree Services in Brisbane Join Date: Jan 2007 Location: Brisbane Posts: 12,994	Re: broken fin on flywheel I reckon you'd pick up a 2nd hand one with all fins dirt cheap. Try this guy, he's a sponsor here. https://apse.mybigcommerce.com/ __________________ Protect your rights to work - Join Australian Tree Association My businesses:- Qualified Brisbane Palm and Tree Lopping \| Stump Grinding Brisbane \| Brisbane - Gold Coast Consulting Arborist

22nd May 2011, 04:20 PM	#3
APSE Semi-mature vigorous tree Join Date: Jan 2011 Location: Aspen Park,Colorado Posts: 76	Re: broken fin on flywheel A Broken fin on the flywheel causes serious imbalance at the higher RPM range, and reduces the cooling efficiency. If you remove the opposing fin for rough balance, the result is a larger reduction in cooling. If the flywheel had 20 fins and you have removed two of them, you have reduced cooling by 10%, and balance is still a way's off. The balance is important to crankshaft seal and bearing life. If the bottom end is compromised, the top end will be next and the engine is likely to become no longer worth repair. It is like likely we have a good used one, please send us a PM if you are interested. Otherwise the life of this saw in "as is" condition is very limited, and there is also a possibility of schrapnel (as in grenade)at higher RPM ranges... Brian and Tina __________________ Vintage Chainsaws, Parts, Restorations, Custom Work, Special Saws on Request and Much More. Please visit our webalbum: http://picasaweb.google.com/APSELLC or our website https://apse.mybigcommerce.com/ APSE-LLC Email:apse-llc@live.com Phone:720-260-0157 Business Hours: Tuesday Through Friday 9-6 Saturday 9-5 Rocky Mountain Time, USA If ya got sumthin' ya can't find we'd be glad to try and help ya! Brian and Tina :

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