Raw Water Circulation Question

[PartsChaser]

The specs:

88 Four Winns 170 Horizon
4.3 Merc with Alpha 1 Gen 1

Got the boat late this summer, only had it out once, and thought it was running a little warm (180+). Knowing I still need to tear the outdrive and lower unit out and do an impeller replacement, I have a question.

As a general rule, while running on the muffs in the driveway, water should be circulating up into the motor, etc, then coming back down through the exhaust bellows, and out the back of the prop...correct?

I can see water going in, as I've unhooked various parts of the cooling system while it was running on the muffs to verify water was attempting to flow uphill from the outdrive to the circulating pump, etc, but cannot see water coming back down out of the exhaust.

Needless to say it will get a water pump, impeller, and any other items I find to replace over the winter, just trying to get a baseline.

Thanks in advance guys!

 

[paultjohnson]

Re: Raw Water Circulation Question

I have the same set up [see below] On muffs most of the water comes out of the idle relief ports. on either side of the of the drive on my boat.. Some water and exhast does come out of the prop hub also. Do you have water coming from the Idle relief ports? They are called idle relief ports because at idle, the prop hub and lower unit is full of water and instead of the exhaust trying to overcome all that water weight and exhaust thru the prop. It can relieve thru those ports.
I would just start with the impellar in the outdrive, Dont just go and replace the recirc pump on the engine as maintenance. I guessn the impellar is all you need if you dont have water discharge. Even if you took the belt of the engine water recirc pump , you should still have water discharging from Idle ports and/ or prop hub. But your engine would overheat soonishly...

 

[PartsChaser]

Re: Raw Water Circulation Question

You know, I dont recall seeing any come out of the idle relief ports now that you mention it, I just remember seeing water stream out the sides of the muffs a bit, wasnt really paying attention.

I've already drained the block and winterized it, so I am making the list for next year. I think the circulating pump on the front of the motor is making a little noise, so I'll replace it and the impeller anyway for good measure.

I am just concerned, and will have to do a little digging once I have the drive off in the spring to inspect and replace parts as required.

 

[Bondo]

Re: Raw Water Circulation Question

but cannot see water coming back down out of the exhaust.

Huh,..??
Where did all the water Go To that you observed flowing through the various hoses you inspected,..??

Generally speakin',... If the circulating pump ain't leakin' from the weep hole,... It's just Fine....