a friend has 2002 powerquest with twin 496 s he had boath sea pumps serviced. now both engines seem to air lock after sitting over the week. to get them to pump you have to remove the lower plastic plug from mottom of the sea pump and hose off of the heat exchanger untill it starts pumping then it's good all weekend. checked the obvious. any ideas

sounds like the pumps are wore out and when sitting the water leaks out and looses its prime,,this happens to alot of 496 sea pumps ,,the only fix is to replace them,,i think teague may make a SS housing for them,,way cheaper then buying new pumps at 600 a crack..

Yeah, the end plates of the housing are shot. Even with new impellers the inconsistencies in the worn cast brass housing combined with a loss of prime will allow the air to just skip the chambers as the pump spins. Several companies make stainless steel inserts and a shorter impeller...I've used one and it worked really well the first year, but after storage the impeller fell apart (don't want to mention brands because I'm not sure if this is an anomaly or not). The good news is the stainless end plates still look like new and swapping impellers had me back up and pumping in a couple hours (spent most of the time recovering the pieces). I have a couple friends running the Hardin Marine stainless pumps on their 496s, however same potential problem with custom impellers. If you go aftermarket, either stainless wear plates or new pump, make sure you buy an extra impeller cause nobody will stock these.

thanks guys i'll pass on the info. the thing that is odd to me neither engine had this problem at the end of last season. now after beeing servised they both do just thinking out loud.

Hardin Marine pumps and don't look back.

My 496 does this everytime I pull it out of storage.... New Housing, new impeller, etc. I just know to start the boat (after a long storage period like winter storage) crack the petcock until it stops pushing air. My housing itself has enough water in it and stays cool so it's not damaging the impeller.