Whats next update

[B Bair]

Posted maybe a month ago about the 8n having no power. this is gonna be a long post. I tried everything you all suggested and did find some problems. I checked the firing order, coil, wires(bad wire on number 4), points and plug gap,jumped the ignition switch,done a spark intensity check,changed the condensor,checked cap and rotor, cleaned the gas tank several times ( there was some dirt in the tank) and filter screens and added a thermostat. No change to the way it was running. Started pulling the spark plug wires and number 3 cylinder was not firing. changed the plug and it ran real good for maybe 10 min. and went back to the same way of running. changed plug again and got the same results. pulled the plug and it wasnt wet. Pulled the valve covers and found the valve clearance was bad, not only on number 3 intake but on all cylinders both exhaust and intake. pulled the head and pulled all the valves. they didnt look bad but you could tell the wasnt seating properly or at all in some cases. I lapped all the vaves and replaced one lifter( the adjuster had the threads messed up). adjusted all the valves and put everything back together. Did find the cylinder had been bored and has the domed pistons in it(crosshatch marks still visible).compression test shows 110 to 120 psi. Ran the tractor yesterday for half an hour and re-torqued the head this morning. drove it around this morning for 30 or 40 min. and seems to run really well. I think it hasnt ran right since I bought it. I wonder if the previous owner had the engine rebuilt and did not check the valve adjustment. Do I need to adjust the valves again after running it a while? I want to thank all of you for your help. I learned a lot this time. Looking forward to mowing this week.

 

[reddog848]

You need to re-torque head bolts while engine is still warm not the next morning when it's cold again.

reddog848

 

[Bob Harvey]

I'd recheck the valves after an hour or so -couldn't hurt !

 

[36 Coupe]

Way to much work for worn out plugs.New plugs of proper heat range would have fixed the problem.-The skip will return.

 

[B Bair]

Will do. Thanks

 

[B Bair]

Thanks. didnt know if I needed to. Guess its not much work to double check them.

 

[B Bair]

plugs was less than a season old. replaced them before starting to tear into the head and valves. Didnt make any differance.

 

[36 Coupe]

What do you have for spark plugs?

 

[B Bair]

Autolite 437 both times.