Did I destroy my engine?

[Husq625]

Hi guys, first post here. I don’t have much experience working on things like this but I am learning.

I recently acquired a Husqvarna 625 AWD mower and learned how to change the plug, oil, air filter, and how to clean the carb so that it would run. Which it did run great for a while, but today I hit a rock real hard. It seemed to cause the air filter to shoot off and take the air box cover with it. I don’t know how that’s possible but it just shot off. It still runs, but very poorly. I noticed a little bit of oil in the air box as well…don’t know what that means.

I checked the “key” using a youtube tutorial and that looked fine, the rockers seemed okay although one felt loose but maybe that’s normal? And the blade is still tight and secure down below. It still starts and idles no problem but as soon as I start putting it to work, it shudders and bogs down and eventually will die if I keep pushing it.

Did I ruin this mower today? Thanks in advance for your time.

 

[Tiger Small Engine]

Hi guys, first post here. I don’t have much experience working on things like this but I am learning.

I recently acquired a Husqvarna 625 AWD mower and learned how to change the plug, oil, air filter, and how to clean the carb so that it would run. Which it did run great for a while, but today I hit a rock real hard. It seemed to cause the air filter to shoot off and take the air box cover with it. I don’t know how that’s possible but it just shot off. It still runs, but very poorly. I noticed a little bit of oil in the air box as well…don’t know what that means.

I checked the “key” using a youtube tutorial and that looked fine, the rockers seemed okay although one felt loose but maybe that’s normal? And the blade is still tight and secure down below. It still starts and idles no problem but as soon as I start putting it to work, it shudders and bogs down and eventually will die if I keep pushing it.

Did I ruin this mower today? Thanks in advance for your time.

Did you pull the flywheel off of the crankshaft to check the flywheel key? Did you have the engine at top dead center on compression stroke when checking valves?

 

[Douglas Lee]

Welcome!!!

 

[Husq625]

Did you pull the flywheel off of the crankshaft to check the flywheel key? Did you have the engine at top dead center on compression stroke when checking valves?

Yes the flywheel key looked perfect still, I’m not sure how to have the engine at top dead center…I’ll look that up and check the valves again.

 

[slomo]

I hit a rock real hard. It seemed to cause the air filter to shoot off and take the air box cover with it.

First off WOW. Never heard that before.

I noticed a little bit of oil in the air box as well…don’t know what that means.

Could mean she is over filled with oil or some blow-by at the rings. KEEP THE OIL ON THE FULL MARK. Check it prior to EVERY MOW. Not a spec over not a spec under the FULL MARK. Protect the oil and she will protect you. Only takes about 21 seconds to check the oil.

the rockers seemed okay although one felt loose but maybe that’s normal?

No. Most likely she has never had the valve lash checked. Depends on how loose you call loose. Download your engine manual. Read it cover to cover. Read it again. Lots of good maintenance tips in there.

It still starts and idles no problem but as soon as I start putting it to work, it shudders and bogs down and eventually will die if I keep pushing it.

Possible blade imbalance. Bent blade you can't see until you compare it with a good blade.

Possible loose engine hold down bolts or missing.

Is shudder a physical movement made by the mower or the engine? Is the engine hunting in RPM? Entire mower shaking at a specific RPM?

Not recommended to idle a mower engine. MAX revs all the time per Briggs, Kawasaki and Kroller to name 3.

 

[Oddjob]

You need to take the flywheel off and see if the woodruff key has partially deformed and moved. They are designed to sacrifice themselves when the blade impacts an immoveable object. You can’t always tell if it is deformed just by looking at it from above. If the flywheel has moved just a little you have thrown off ignition timing. Fingers crossed, a new key will fix this. But, I suspect you did internal damage, maybe bending the crankshaft. With the sparkplug out, tip the mower on the side and turn the blade by hand. See if it is turning true or wobbling like a warped LP. The cam that tells the valves to open and close may have been damaged, which would account for the sloppy valve lash. Say a prayer that a new woodruff key fixes this. OTOH, this could be an opportunity for you to learn about engine innards. Best wishes.