HELP!! 2001 Volvo Penta SX running hot

[stouchton]

Are your risers overheating?? If not it would seem you have adequate water flow.

Raw water cooled, correct?

If you trim up slightly does the problem change? (indicates cavitation)

Timing/Mixture effects engine efficiency - less efficient you will make more thermal energy and less mechanical energy - thus produce more heat. There is a limitation on how fast water can exit the engine block.

If you put clear hoses from the thermostat housing to manifolds and observe bubbles this can indicate a head gasket issue (or a crack....)

If you have a restriction of the exit nipples on the thermostat housing it usually shows first with overheated riser.

OK.... this was just some thoughts to stew on.

 

[stouchton]

Also - how did original engine fail?

 

[Searay205]

Yes 18 was replaced. We are done with this boat. Saw some tiny bubbles nothing to indicated blown head gasket or cracked head. Runs all day 3300rpm then anything above overheats. Boat is for sale, sooner gone the better. Absolutely everything has been replaced and checked and checked.

 

[Searay205]

To bring closure. The aftermarket MSD distributor had to soft of springs which advanced the timing to far causing the overheating. Adjusted timing based on full advance, didn't care what base timing was and no more overheating at higher rpm's.