What symptoms does poor valve adjustment bring to the table...?

[Thorpe]

Can valve adjustment cause poor hot starting conditions? A motor that will turn over fast and normal with the electric start, pop a little, but not want to come to life? Motor starts great cold... :wondering

[christph]

Yes, valves that are out of adjustment can cause poor starting, especially when hot. You have to remember, as valves wear the tolerance between the cam and the rocker gets closer. As parts heat up they expand and the tolerances get even closer, sometimes to the point where the cam and rocker are in continuous contact, whether the valve is open or closed. If it gets bad enough the valve never closes because it is always held open--even if only a bit--by the rocker. This results in a loss of compression and hence difficult starting. It also means the force of the valve closing is exerted on the rocker (and not the valve seat) and the valve will overheat because it is no longer coming into full contact with the head, i.e., the valve seat is where it sheds most of its heat. In short, a lot of problems can develop due to a valve out of adjustment.

[Thorpe]

197865

Thankyou guys for all your help... Diagnostics are great, but if one of you would have said the mechanic was a dip$hit, you woulda been spot on! Bill, (atc007) you were the inspiration to fixing my stupidity. Valve adjustment looked good, fresh plug, starts great, warm it up, starts like crap! Well, let's go back and try that ether trick again, but this time lets get that dirty air filter out the way... But first for grins, let's try firing it without that dirty filter... Pops off every time! Simplest thing, was overlooked... Gonna go kick myself in the nuts now...