contractorman
May 28, 2012, 02:39 PM
I have a Craftsman garden tractor with a 26hp els engine. Took it out this year and noticed how rough it was running. It ran smoother under load but at an idle it was pretty rough. A friend suggested some carb cleaner which I tried and it seemed to run better but not great. Bought a B&S tune up kit and did the tune up. New air filter, oil, oil filter, fuel filter, plugs and gas additive. Well it seems to run quite smoothly now except for one big issue. It lacks power. I'm far from an expert so I don't know that much about small engine repair or the proper names of things so I tried what I know.
I thought I would check for spark on both cylinders. The curious part was this. When I pulled the plug wire from one side to check spark, the engine wouldn't start. Hmmmm, replaced the wire and pulled the other off instead. The engine started and ran as smoothly as it did with both wires on! There was spark, so I pulled the plug and just cranked the engine to see if there was some compression and there was. I then removed the valve cover and just cranked the engine to see if the valves were moving and they were. After all that, to me it's as if the engine is running on 1 cylinder which judging by the power issue made some sense to me.
There is more history with this engine from 3 years ago that I need to mention. This is where someone is going to say well why didn't he tell us that first! What happened was there was a mouse nest in the cooling fin area of the cylinder in question. Not realizing it , the cylinder overheated, the valve guide worked its way out and a push rod broke and fell into the engine. I took the whole thing apart, got the broken rod and rebuilt the engine. I had a repair shop set the valve guides and I put the darn thing back on. It's been running prety well until this issue arose. Is it possible that maybe the guides have moved again maybe just enough to not allow the valves to work properly? Sorry is that's a dumb question? I'm just trying to come up with something. Any help would be greatly appreciated so thanks in advance.
I thought I would check for spark on both cylinders. The curious part was this. When I pulled the plug wire from one side to check spark, the engine wouldn't start. Hmmmm, replaced the wire and pulled the other off instead. The engine started and ran as smoothly as it did with both wires on! There was spark, so I pulled the plug and just cranked the engine to see if there was some compression and there was. I then removed the valve cover and just cranked the engine to see if the valves were moving and they were. After all that, to me it's as if the engine is running on 1 cylinder which judging by the power issue made some sense to me.
There is more history with this engine from 3 years ago that I need to mention. This is where someone is going to say well why didn't he tell us that first! What happened was there was a mouse nest in the cooling fin area of the cylinder in question. Not realizing it , the cylinder overheated, the valve guide worked its way out and a push rod broke and fell into the engine. I took the whole thing apart, got the broken rod and rebuilt the engine. I had a repair shop set the valve guides and I put the darn thing back on. It's been running prety well until this issue arose. Is it possible that maybe the guides have moved again maybe just enough to not allow the valves to work properly? Sorry is that's a dumb question? I'm just trying to come up with something. Any help would be greatly appreciated so thanks in advance.