5.5hp Briggs and Stratton OHV.

The engine has always started easily and run well, however over the past year it's been somewhat hard to start. When pulling the starter rope it sometimes developed resistance (from engine compression) half way though the pull snapping the cord out of your hand. Still it started if you used half pulls.

This year however there was no resistance when pull starting at all and of course it failed to start. Good spark, but when removing the air filter It was saturated with fuel. Trying to start the engine with filter removed and gas just sprays out the carborator into the air filter. Taking off the OHV cover, the rocker arms/valves didn't appear to be moving when the crankshaft was turned. Could it be bad timing or valves not seated right? I was half expecting to find a broken tooth on the gear driving the cam shaft, but it looks to be intact. Can the plastic cams ever shift on the metal shaft?
The history with apparent compression at the wrong time when starting it makes me think it could be more of a timing issue, but I'm rather a novice at this.

Is there anything I should check/replace before I reassemble it?

-Tim

well if the rockers didn't move at all it would lead down to the cam, or the pushrods. the engine looks good inside the engine right? connecting rod intact and all?

and check your flywheel key!!!

the valves are binding in the guides spray them down good with wd 40 and work them up and down till they are loose

I agree with scrench...sounds like the valves are rusted in the guides. I'd also be willing to bet that this is a mower thats stored outside. I say this because all the times I've seen this problem it was because the mower sat outside and water ran into the carb and back into the breather on the valve cover.

yea outside not good but i have seen old tarnished fuel do it too

yeah, and the worst thing you can do, keep em outside in the rain under a tarp.

It isn't stored outside. I had a better chance to check it tonight and rods, valves, rocker arms, etc. all move freely. And the flyweel key is good. But, the gear on the camshaft can be turned pretty easily with my bare hands while holding the shaft still. I'm assuming this isn't typical?

My other problem is that it doesn't seem to have a normal model number on it. It was purchased several years ago as a replacement on a tiller. The sticker on the flywheel cover lists:
Family: VBS205U1G1RA:EM
Displacement: 205cc
Model: 12H0HV

Of course this doesn't correspond to the models on the B&S website. It does look identical to 126332-0036 with camshaft #693404 http://www.briggsandstratton.com/ipl/pdfs/100/MS5718.pdf

teeth and all are fine but the lobes don't move? you hold the cam tight while turning the cam gear and all that turns is the gear., oh and too the cover problem, the engine is a replacement? or a rebuilt replacement? its probablly not the right cover unless it came out of the box like that. but yeah the cam just may be gone if it does what you say its doing, probablly off timing to begin with and slowly progressed till it did what it did, says powerbuilt on the engine cover right?

Thanks for the input. I got the new camshaft early this week and installed it tonight. It runs just fine now, and I think with less vibration than the last time i had it running. Of course now that the tiller is running it's raining :)

yeah its usual, you get something running you need, and then it rains, of course after it rains it will make the ground softer to till.