overheating

[87saleen171]

I have yet to enjoy my boat. 2 trips to lake, 2 impellers gone. Boat runs no warmer than 180 in driveway thru a flush kit(more on that later). But overheats when @ lake, have yet to leave no wake zone. Completely went thru cooling system this week. Dislodged all old impeller pieces & removed hoses for inspection. Right now I'm thinking it was a faulty thermostat. Also leaning towards removing flush kit, rerouting hose from intake straight to impeller pump. Right now there is about 6 or 7' of hose from intake to pump(seems like along way for pump to pull water). Anyone have any suggestions??? Thanks for any help. OH yeah, its a 350 mercruiser carb motor

[Tanner]

I have yet to enjoy my boat. 2 trips to lake, 2 impellers gone. Boat runs no warmer than 180 in driveway thru a flush kit(more on that later). But overheats when @ lake, have yet to leave no wake zone. Completely went thru cooling system this week. Dislodged all old impeller pieces & removed hoses for inspection. Right now I'm thinking it was a faulty thermostat. Also leaning towards removing flush kit, rerouting hose from intake straight to impeller pump. Right now there is about 6 or 7' of hose from intake to pump(seems like along way for pump to pull water). Anyone have any suggestions??? Thanks for any help. OH yeah, its a 350 mercruiser carb motor

How's the impeller housing? Checked the bearings or looked for grooves in the pump?

[87saleen171]

no grooves in housing. Do you just check pulley for play in bearings?

[Tanner]

Essentially, yes. Or you can disassemble the pump and inspect them physically. But the fact that your shredding impellers back to back says there's something up with your housing I'd bet.

You should probably change the housing out every 5 years. Since you've got a Merc. that's definitely an older model Tige. When was the housing last changed, If ever?

[87saleen171]

checked for play in bearings --- none
checked housing for grooves or blueing---- none
replaced hose from tstat housing to water pump(on motor)
replaced tstat
checked all hoses for blockage

Gonna give a try tomorrow, results to follow

[Tanner]

What are the chance you have a inline strainer that your missing and it's clogged? If not, may pull your water pick-up or the hose from your pick-up and make sure it's not clogged. Good luck!

[TRD]

I had this happen and found about 6 pcs of my impeller in the exit side of the impeller. The screen stops the pcs, sucked them out w/ a shop vac. Replaced the hsg and impeller and worked fine after that.

[TigeTrojan]

I had a similar problem and was told that the seal is going bad on my pump. It works fine hooked up to the hose because the hose is giving enough pressure to keep the water flowing to the impeller. But when I am on the water, the pump is sucking air through the bad seal instead of sucking water from the intake hose. That's just what I was told by a mechanic at the lake, haven't found out if that is really the case yet.

Good luck, hope you get to enjoy the boat soon!

[87saleen171]

Tige Trojan-- thanks for your input, that is along the lines of what is wrong with mine. Ran it in driveway for 30 min. last night no problem. I also think the amount of intake hose(6-7' for flush kit) has a role in it to. Dont have fake a lake yet so my only way of testing is with flush kit. But plan on removing since it now is fresh water only boat.