Engine not starting

[NCMau]

I have a Tucumseh H60, 6 HP horizontal, mounted on a Troybilt tiller. The machine was in semi-retirement status for the last 10 years. It worked at that time. But now I’m having really hard time getting this engine running. It is electric, so my arm is still attached to my shoulder. Here’s the scoop:
Installed a new Chinese carburetor, plenty gas to the bowl, new gas.
Point ha a good spark.
Gas gets to the cylinder, (Spark plug is wet).
Compression is 90 psi.
It does not fire, even with starting fluid.
So what’s left, timing? If that’s what it could be, how do I check it?. Does this engine have a sheer pin?
I love to get some suggestions before I start getting inside.

[Deere2me]

Download a manual from the old forum, here:http://www.perr.com/phpBB3/viewtopic.php?f=15&t=8003
And , Oh yeah......read this :http://ppeten.com/forums/viewtopic.php?f=3&t=11

[bobodu]

My first guess would be...it you have spark and you have fuel...the only thing left is compression. I would check for a stuck valve. Pull out the plug and LIGHTLY cover the hole with your thumb. Feel for a good solid push and pull. Valves can get a coat of varnish from old gas and stuck wherever they stopped last time it ran.
Oooops...I see you have 90 psi. Bit on the low side. Did you check that with the throttle wide open?

[madmantrapper]

Check the flywheel key, spark at wrong time.

[NCMau]

My first guess would be...it you have spark and you have fuel...the only thing left is compression. I would check for a stuck valve. Pull out the plug and LIGHTLY cover the hole with your thumb. Feel for a good solid push and pull. Valves can get a coat of varnish from old gas and stuck wherever they stopped last time it ran.
Oooops...I see you have 90 psi. Bit on the low side. Did you check that with the throttle wide open?

It was open. What's the difference, is it less compression reading in this case?

[NCMau]

Check the flywheel key, spark at wrong time.

Yeap! It would be next step. I hope that's all is gonna be.

[bobodu]

The throttle must be wide open for an accurate reading. If the piston is pulling a vacuum on the way down, you're gonna see lower pressure on the way up.

[dakota2]

Did you replace spark plug?

[NCMau]

Did you replace spark plug?

Good spark from the plug.

[bgsengine]

Did you replace spark plug?

Good spark from the plug.

doesn't matter - plugs - even brand new ones out of the box- can fail and not fire under compression.

Replace it with a new one.