Needed to take the serial number sticker off to read it:

247.384260

CO91L3

Any suggestions are welcome before I start to dig into it further. I have had similar problems with other mowers with B&S engines.

Thanks!

Vince

Thanks! I didn't know who it was made by. I was going to pull the plug and see how it looks out of curiosity. I am familiar with the other parts as I've been working on cars, trucks and motorcycles for many years as a hobby. I would like to fix and keep this mower as it is lighter and simpler than the other one I have as a back up, which has driven front wheels and all that nonsense (It was free, supposedly needing only new rubber fuel lines). My problem is that I'm limited on time (aren't we all) and don't want to waste a few hours taking apart the engine if it's not easily fixable/worth fixing. I'll post my findings hopefully by this weekend.

It's a 4-cycle engine, so there will be only one compression stroke out of two blade revolutions. And, there is a compression release for easier starting, so you won't feel a lot of compression. Going by the title of the thread, it sounds like the engine is overheating. Make sure you have oil at the proper level and the cooling fins under the air shroud are clean. You're supposed to take the shroud off yearly and clean the engine. There are a number of other things that could cause this but it could be that its just worn out.

this mower is at least 25 years old. in 2009, Tecumseh stopped manufacturing engines. Assets were sold to another company and this old stuff is no longer supported. Some aftermarket parts may still be around.

Since your compression seems to come and go, there is a chance of a sticking intake valve. This occurs when ethanol fuel leaves residue on the intake valve stem.

Thanks, guys. I knew the mower was older from it's simplicity. It was full of fresh oil and the fins were clear. Overheating is a possibility, as it was 90 degrees out and in the sunshine, and I had been cutting grass for over an hour. The compression release and/or valves may indeed be an issue, as it had weak compression compared to the other mower I have. I am looking forward to opening it up when I have time and seeing what's going on in there!

Vince

Hot weather and extended use would not cause overheating on an engine in good condition. I agree most likely its worn out or there's a sticking valve. I would dose the oil and gas with Seafoam and try to use it a few times to see if it unsticks valves and/or rings.

Thats an Eager1 After buying 2 in succession, I started dumpster diving for better mowers.

I know it's an old thread but I can't help reading that you said you were going to look at the spark plug but never said you actually did or what you found.

It sounds to me when you describe turning it over that it's just going through a normal cycle. There will be resistance on compression and even with no ignition once it's past top dead center the compressed air in the head will push the cylinder down making it feel like part of it turned easier.

In mowers oil level is not trivial because their has to be enough oil to get splashed up in the bottom part of the cylinder to seal the compression rings an and make compression in the head. Not enough old and the gasses just blow past the rings.

I can remember being about 12 and trying to get an old mower a neighbor had given up on started. I'd learned how engines worked so I made sure it has spark but still after repeated vigorous pulls (it was a wind up rope lol) I'd find the plug wet. I had tested the plug resting it on the head and turning it over and it sparked, and the plug got wet so I knew their was fuel getting there. Something should be happening but it was dead as a door nail. I spent hours doing who knows what but then I checked the oil level not even thinking it could have anything to do with anything and and found it empty. There had to be at least a little because it was not turning hard but there was nothing on the stick. So I put oil in it, absent minded checked it over again and then gave it some more pulls. 3 or so pulls in it fired a few times then died. I didn't have the choke on because I figure since I'd seen fuel on the plug if I choked it it would be too rich. But since it had fired I set the choked, it roared to life and my days of pushing around an old reel mower were finally over!

Not enough oil = not enough compression.