I bought a used MTD snowblower with a 12 hp OHSK120 engine. When it runs, the exhaust manifold is red hot, even when not under high load. It doesn't seem like it has as much power as it should, and turns over very easy (I use the electric start). It also starts hard. Now it won't start at all, and after checking the basics and a new spark plug, I checked the valve lifts. The exhaust valve lifts open for part of the compressions stroke. The service manual doesn't state that this model has either the MCR (mechanical compression release), nor the RCR (ramp compression release). Not sure if it may have a problem with camshaft or am I barking up the wrong tree? Any ideas?

i've heard a coil incorrectly spaced can cause the motor to shut off when hot , run funny ect . i don't know how true that is but it might be worth a look

The cause of the red exhaust could be a condition in the carb. If it has a screw under the carb bowl by all means give that joker some gas by opening the screw
about a turn. If its not that try cleaning the main jet.

Mike