MerCruiser 5.0 will not start/run in idle mode (Carb Engine)

[Robertse]

MerCruiser 5.0 will not start/run in idle mode. Recently the motor stalled and will not run in idle mode, it will start at high revs but when I place it in idle mode it will stall. I also discovered there is water mixed with the oil sump (the engine oil is milky as obtain from the dip stick). Prior to this issue the compression reported 150-180 PSI which is good. Any feedback will be appreciated; I will do another compression test, however form my experiences with motor vehicles the signs are pointing to cracked head gasket. If it is a head gasket, can you use a Head Gasket Repair Sealer or Block Sealer in Boats, if so how?

 

[bondo]

Ayuh,.... The idle problem sounds like crud in the carb's idle circuit, so rebuild the carb,....

The dipstick tube builds condensation, so drain the oil, then decide whether the block / head need pressure testing,....
'n No, sealers don't work, tear it apart, 'n properly repair it is the only option,.....