350 mag water pump impeller change question

[stormyj]

Morning all. I did a stupid thing on a new to me boat. Forgot there are thru hull valves for the engines and started them up and ran them for a while. Whats that whiney sound? Oh, ****. so, now Im going to open the pumps up and change the impellers, cause Im sure they are wasted. I ran for probably 10 min with no water in them. It is a close cooling system, so the engines didnt get too hot , but I know those impellers are wasted. ive changed many impellers, but alwasy did it with boat on a trailer. This is a bigger boat in a slip. Looking at the water pump, two hoses aft, one is red and leads to a check valve. Does taht check valve stay shut if I remove that hose? I dont want water spraying everywhere while I try to get the hose back on. Reminds me of a joke. Anyway. I watched a video on you tube where the guy said he removed the hose from the aft side of the check valve and plugged it. Well, what is the check valve for? Or do they get clogged or stuck? I am on the chesapeake so there is growth. Any idea would be very helpful. I probably will get a plug to just have in case. Dont know if my bilge pump will keep up with that hose. Its a big one. Anywho. Thanks for your help.

 

[alldodge]

Serial number of motor?

With thru hulls just close them. When the pump hoses are disconnected water will pour into the bilge but only a gallon or so. Check valves are used to keep the hoses more full at all times instead of letting them drain back each time the motor is shut off.

Need to find all the pieces and anything not found can get stuck in other areas (check valves, coolers, heat exchanger, etc)

 

[alldodge]

The thru hulls should go to strainers and then to pump motor. If they do something different let us know before doing anything

 

[flashback]

Would 10 minutes running burn up any soft parts in the exhaust system? I guess it is fed by the same pump?

 

[alldodge]

It could, they would be very hot in 10 minutes with no water going thru
Check the boots

 

[stormyj]

The thru hulls should go to strainers and then to pump motor. If they do something different let us know before doing anything

Yes, thru hull/seacock, then strainer, then to engine.

 

[stormyj]

It could, they would be very hot in 10 minutes with no water going thru
Check the boots

what boots are you talking about. On the risers?

 

[stormyj]

Serial number of motor?

With thru hulls just close them. When the pump hoses are disconnected water will pour into the bilge but only a gallon or so. Check valves are used to keep the hoses more full at all times instead of letting them drain back each time the motor is shut off.

Need to find all the pieces and anything not found can get stuck in other areas (check valves, coolers, heat exchanger, etc)

SN of motor is OW634563

 

[alldodge]

what boots are you talking about. On the risers?

I don't know how your configured, but the boots that connect the exhaust elbows to pipe. If you have mufflers it can over heat them as well. Anything made of rubber could be damaged

 

[stormyj]

I don't know how your configured, but the boots that connect the exhaust elbows to pipe. If you have mufflers it can over heat them as well. Anything made of rubber could be damaged

Ill take a look. I dont think it got taht hot, being a close system, it only got up to about 170f I was watching the temp gauge right after I remembered to open the valves.

 

[alldodge]

The motor was at 170, exhaust temps without water are above 800

 

[QBhoy]

You should have a strainer that is higher than the water level outside anyway…I’d think.
I did a pump on a shaft drive 350 recently. Good idea to loosen and remove the two mounting bolts for the pump bracket. Slip belt off the pulley and remove the whole thing. Cable ties and grease are handy to get the new impeller in. Should be able to slip the belt back on (without it being removed from any other pulley, then get the two bolts back in one at a time.
Make sure the lid on the strainer is tight, or it won’t pull water through.

 

[flashback]

The motor was at 170, exhaust temps without water are above 800

I'm dealing with a similar situation And I only brought it up because I have an exhaust hose that's crispy, . I have nothing to offer you but I lurk All the threads, it's knowledge I'm after.. I think my elbow is rusted to where the water won't flush. I will not highjack your thread but will watch..,and I hope you get the knowledge you need. This forum is a library

 

[stormyj]

I'm dealing with a similar situation And I only brought it up because I have an exhaust hose that's crispy, . I have nothing to offer you but I lurk All the threads, it's knowledge I'm after.. I think my elbow is rusted to where the water won't flush. I will not highjack your thread but will watch..,and I hope you get the knowledge you need. This forum is a library

Yeah, Im going to check all the rubber parts on the exhaust to make sure nothing got fried.