Need help on how to back flush alpha one gen one

[motor boater]

I have a 1987 Four Winns freedom 160 that has what I believe is the Alpha One gen one on it. It over heated during the memorial day weekend on lake mead and I am now getting ready to replace my impeller as well as the housing, seals, gaskets and O rings, as well as the oil and possibly a water hose.

The water hose i'm talking about is located to the left of the thermostat housing and cover assembly and connects that to the engine circulating pump. When I squeeze this hose, I feel something solid inside, and it is crunchy all round it. I'm getting ready to remove it to see what is going on. Hopefully I haven't completely damaged my engine. This is my first boat, and the first time I will have EVER worked on it since I bought it 2 1/2 years ago. :facepalm: I know I should have already changed the impeller. (I already hate myself for neglecting that, and thinking it would be ok).

Anyhow, I just found a how to on how to drop the lower unit and change the impeller and all that, so I believe I'm ok in that area I hope (fingers crossed). but I have read something about a back flush online which I think I want to do.

Something about connecting a hose and turning the water on to see if the water flows from the engine area back out through the outdrive where you would normally connect the water ears. Here is a diagram of my cooling system water flow, can anyone tell me how I would go about doing this? and where I would connect the hose to. I want to make sure everything is working fine and there isn't anything blocking or obstructing the water flow before I re-attach the outdrive and fill up the oil. ANY HELP IS APPRECIATED.

One more thing, should I be replacing the thermostat while I'm doing all of this other work? is it necessary?
and what other things should I consider changing, and why?

SORRY for the novel I just wrote.

 

[ktbarrentine]

Re: Need help on how to back flush alpha one gen one

If this is the first time you are doing maintenance in the 2 and 1/2 years you've owned the boat (assuming you've been putting "some" amount of hours on it in that time), then you need to do more than just drop the lower... you need to visit the stickys at the top of this forum for more info on routine maintenance, and to get the right service manuals for your engine and drive. You need to remove the whole drive to service your u-joints, check condition of your gimbal bearing, all your bellows, check alignment, just to name a few of the more important things besides the typical impeller change-out. Good luck!
KB

 

[motor boater]

Re: Need help on how to back flush alpha one gen one

okay thank you, I did not take it out last year but I did take it out the year before and I probably put about 24 hours on it. however I don't know what kind of maintenance the previous owner did before I purchased it from him

 

[Eric 3.7LX Alpha 1]

Re: Need help on how to back flush alpha one gen one

You should also be servicing the engine yearly as well. Tune up, filters and oil change.

 

[motor boater]

Re: Need help on how to back flush alpha one gen one

Yes, I do understand the importance of yearly maintinance now that ive had to learn the hard way, lol. But still my back flushing question is not being answered.. ANYONE??? I will be disassembling the out Drive tomorrow and looking around to investigate the condition of the bellows and The gimbal bearings along with the impeller housing etc.

 

[Eric 3.7LX Alpha 1]

Re: Need help on how to back flush alpha one gen one

If that hose your referring to is a larger diameter, many times a spring is installed in the hose from the factory so the hose won't collapse when it gets hot. The spring doesn't effect flow at all.

When you pull off your outdrive, you'll see the water passage that feeds the engine. Sealed with an O-ring in the picture below from Fishermark.

Remove the hose off the thermostat housing as noted in your diagram coming from the drive, and back flush it with a hose, it will come out the water inlet at the bellhousing in the picture below.


Put that hose back on, and stick your garden hose in that passage and run the engine with the drive off (water on), see how the temperature reacts.