Need Help! Bad! Mystery Wont Crank Murray.

[ThatGuyYouKnow]

Okay two days I have been fighting this Murray 3.5 Briggs Classic. This thing just will not crank it wont do anything at all! It sits atop a 20in push mower and I have tried 3 different coils and 2 flywheel brakes even different spark plugs. original spark plug was a RCJ6Y or to my knowledge new plug no change so I tried a RJ19Lm and nothing. When I got it the pull starter was broke so I replaced the top with another that's the exact same. The Model is a 9d302. Please help.

 

[davbell22602]

Will the engine turn over with spark plug out? If not the engine is probably seized up and not repairable.

 

[ThatGuyYouKnow]

It spins like a top. The piston moves up and down free and no sputter nothing with the plug out just spins faster. Could it be a compression problem?

 

[davbell22602]

It spins like a top. The piston moves up and down free and no sputter nothing with the plug out just spins faster. Could it be a compression problem?

Do the valves open and close?

 

[ThatGuyYouKnow]

From what I can tell but not sure I haven't removed the head yet. I guess I should may do it tomorrow thanks for your replies ill look and see the ill post back

 

[ThatGuyYouKnow]

Okay removed the head and found the combustion chamber caked with carbon and the lower bolts were barely tight. The valves operate fine so I believe the head gasket is my culprit.

 

[davbell22602]

Okay removed the head and found the combustion chamber caked with carbon and the lower bolts were barely tight. The valves operate fine so I believe the head gasket is my culprit.

Make sure to clean all the carbon off the head and top of the piston. Also I would put new spark plug in it.

 

[ThatGuyYouKnow]

Thanks for your help dumby me I should have checked that but oh well. thanks again.