My four year old 14.5 B&S engine (lawn tractor) was running great one day and then suddenly started running very rough. I changed the oil, cleaned the carb, and did some general cleanup on it.

It would start and run, but still very very rough. It also had a clinking sound coming from within it. After an hour of starting it trying to get it running, it simply stopped wanting to turn over at all, and finally the starter burned up.

I also noted that the plastic gear on the starter was completely worn from trying to turn the engine over, but the engine not turning over.

I replaced the starter and now it turns over about 3-5 revolutions and then stops turning over. It won't start at all. Everytime I turn the key to start, it turns over a few times and then stops.

Any ideas? It almost feels like the piston is seizing, or at least trying to.

By the way, if I remove the spark plug it turns over fine. But when I replace it it only turns over a few times.

Last thing: I can spin the engine by hand using the flywheel at the top of the engine...not easy, but it shouldn't be I wouldn't think.

Thanks!

Is this a over head valve engine? have the valves adjusted, i'd also have the pushrods checked to make sure they are not bent.

when you set the valves make sure the small round spacers did not come off the top of the valve stem between the rocker arm and valve common problem with that engine 28b707 280707

Thanks to both of you for your guidance.

I removed the OHV cover and removed the rods and the intake rod was severely bent. [IT IS THE BOTTOM OF THE TWO RODS...is this the intake?]

It's funny that the exhaust rod (top) appears to be made of steel, and the intake rod (bottom) appears to be made of aluminum. Maybe not, but one is black and one is bright silver and they weigh different.

Thanks again! I'm only $6 away from a running mower again!

Any idea what could have caused this rod to bend? Should I be checking for some other problem or is it typical since the rod is (or appears to be) aluminum?

Thanks!

Aluminum one is on the exhaust side, for better heat transfer. Its aluminum, so it does bend easier.

I went to my local store to buy the exhaust valve rod and it was steel, with ball sort of ends on it (like the other valve's rod). The aluminum rod did not have ball-like ends...they were simply tapered a bit.

The part number the local guy gave me matched the part number for the exhaust rod, but b/c it didn't match the original bent rod in type of metal or end design, we decided that I must need the intake rod....which he did not have in stock.

So, I ordered (online) an intake and exhaust rod...just in case.

Thanks....so the exhaust is the bottom valve?

Replaced the starter, the soleniod (apparently burned up trying to start with bent rod), and the exhaust push rod.

Engine now turns over fast and strong, but it won't start.

Gas getting into engine (and apparently sparking ok too), as small flames shoot out from carb when trying to start.

Thoughts?

Reminder: 14.5 B&S, OHV, single cylinder, on a Cub Cadet mower.

intake valve might be bent or the rocker too tight take the valve cover off and the rocker arms off and look at the valves at the springs see if one is taller than the other or you could turn it over by hand with the rocker arms off and the plug in it and listen for compression leaking from the intake valve but i bet its too tight . or another thing that could have happened is the seat might have came loose from the head i would just take the rocker arms off and turn it over and see if it holds compression

Thanks again for the help. Great forum.

I removed the rocker arm cover and turned the engine over by hand, and noticed that the exhaust rod was not moving. Apprarently I missed the seat on the tappet. So I got it seated right and now it moves in / out and once put back together it started immediately!

Yippee!