husqvarna yth2448 was serviced 1 mo ago and was fine. Today it started but sounded "louder" . It seemed alittle under powered when going in drive. When I engaged the blades the power loss became more evident especially going up small hills. I could see fuel in the filter, about one eighth full. I disconnected the fuel line leaving the pump and it was working. I could unplug the right spark plug and engine performance stayed the same. Unplug the left plug by itself and the mower would not start. I removed the right spark and replaced it. Engine still soundsl loud as if missing and still under powered under a load. The spark plug is getting good spark when tested. Help
Hello, welcome to Just Answers. My name is XXX, XXX I would like to help you with your question
do you know what type of engine you have?
24 hp els725 b&s
ok, that helps. do you have access to a compression tester?
I suspect that one of your valves has seized in the head on the right side. it is a common failure on this engine
had a similar problem when it was 1 yr old. it had a intake manifold ring leak
how to fix a seized valve?
first thing to do is to confirm or disprove. if you pull the valve cover on that side, you may find that one of the valves does not go down as far as the other when spun by hand with the plugs out.
i have also seen the rocker arms come loose, in which case you will have a piece fall out when you remove the cover
intake appears to be made of kevlar plastic , could it be warped?
If I take off head will I need new gaskets?
it certainly could be, but the louder noise you describe goes more with a stuck valve. an easy check would be to spray a bit of carb cleaner or penetrating oil around the suspected warp area. cleaner will make it try and run, oil will also make it try a bit, and smoke some from the exhause
If the valve is stuck, how to fix?
if the valve is stuck, what happens is that the guide for the valve moves inside the head. the repair on this engine is to replace the head. they come complete with valves and all. pretty inexpensive when compared to others. usually around 100 or so.
if it were me, i would pull the valve cover before making any decisions. sometimes it can surprise you and be quite simple!
your description on your tests was very good, rules out almost everything but compression. which is where the valves come in
24 hp els725 briggs and stratton seized valve
Service Manager and technician for small engines and lawn equipment