[campsafe]

What items need to be replaced when you have this problem.

[fordsohc46]

what are your readings? what size engine? are you checking compression with all 4 plugs out and with throttle at wot? depending on readings you might could decarb the motor. with help from guys on this forum i decarbed my motor and gained 25+ psi per cylinder.

[Dennisanoka]

Just what Fordsohc46 said, list the hp/model of your engine and what the compression readings were while using a fully charged battery capable of turning over your engine at approx. 300 rpm. Take the readings more than once to be sure of consistency.

Regarding your question as to what might need to be replaced, it depends on what is really wrong with your engine, so maybe not too much to maybe a complete re-build.