Husqvarna mower finally starting; now throttles with poor power

I have a Husqvarna 5521 CHV self-propelled push mower with a 5.5 HP Honda GCX-160 engine. It had run fine until I let a friend's son mow the lawn while we were on vacation, and I came back to find the blade beat to a pulp and the fuel tank empty.

Since then I've replaced the blade, but the engine has given me problems. At first it wouldn't start. I checked the spark plug and the air filter and both seemed in working order. Took apart the carb and found some debris floating in the bowl. The float seems fully mobile, and I didn't notice anything jamming any of the jets. I flushed that debris out and went through the carburator pretty thoroughly with carb cleaner.

It still wouldn't start until I added some ether to the carb, and since then, it's fired up on the first pull every time. I've also added a bit of Seafoam to the fuel and this seems to have added a little better performance. Also replaced the spark plug, which didn't seem to be a problem, either.

My problem now is that when it starts it initially surges at full power, only to throttle back and forth and eventually lose power. I get about 5 minutes of decent running with maybe 30 seconds of normal power, at which point the engine begins to lose power. Through all of this is a cloud of white smoke.

I'm a bit new to all of this, and frankly, tinkering around on it has been kind of fun. All help greatly appreciated.

 

If the blade was ""Beat To A Pulp"" I'd check the flywheel key to see if it has partially sheared... & if so replace it.. Try it without the air filter as these Honda's like their air & even when you see light thru the filter, they run rough,,,Especially if the filter got wet... Even try a new spark plug... If all this fails,, You may have to dissasemble & soak the carb ..Blow it out with air & put a kit in it... Roger

 

The flywheel is fine. The oil is changed. New gas in the tank with SeaFoam. I've changed the oil. I've soaked the carbureator in a bath. Resprayed carb cleaner. Adjusted the carb. Spark plug is fine and changed (not that the old one didn't fire).

It ran the best it's run today in weeks, and while it nearly bogged down a few times, I nearly got the front lawn mowed, it quit belching smoke, and it wasn't shaking quite as bad nor losing nearly as much power. Then it just quit and now won't restart. This is after it had fired up every time on the first or second pull now for the past 10-15 starts.

The only thing I can think of is that it appears it's leaking some oil on the spark plug.

Any suggestions?

I'm to the point of taking it to the shop.

 

I believe the GX 160 Honda engine was the one that had a cam problem. It showed up here on a thread with symptoms that included "walking across the floor". It was on a generator or a power washer. A possibility.

If yours was belching smoke, then quit, I would check the oil level, you may have ran it out.

 

You may have more than one issue with this engine but I feel you still have a carburetion problem. Look at the link below, if you did not clean every part of the carburetor as shown it may be the source of your problem. Many Honda carburetors have welch plugs covering the transition ports and the must be removed to correctly clean the carburetor. The chart below does not show the welch plug but most carburetors use them.

A leakdown test or even a compression test would rule out cylinder/valve problems. I prefer the leakdown test. I have no technical data for the GCX-160 engine. Therefore, I do not know if it utilizes automatic compression relief (ACR). If it does not have ACR, you should have around 70 PSI compression.

If I were working on this engine, I would install a new plug. It may not be the plug but I learned the hard way to install NEW plugs.

http://www.honda-engines-eu.com/en/images/59138.pdf

Building and Using a Cylinder Leakdown Tester

 

After some thought I think you may have the engine model incorrect. The owners manual shows a GCV160 engine. Is it a GCV160?

http://weborder.husqvarna.com/order_...7_O0702020.pdf

This is for your carburetor:
http://www.honda-engines-eu.com/en/images/59139.pdf