1981 Sundancer no raw water strainer?

[hpcrank]

I am working on a 1981 260 Sundancer with the 330 hp. 7.4 BB Chevy engine. Having read a number of posts discussing raw water strainers I question why my boat does not have one. My boat is and has been a fresh water boat it's entire life. I have not had this boat in the water yet so would like to know if this boat came from the factory without a strainer or if I should install one before launching. My boat has a raw water pick up thru the engine bay hull with a raw water pump on the engine as well as a circulating pump on the engine. This boat engine has an open cooling system.

Thanks in advance.

Hpcrank :huh:

 

[Lazy Daze]

Inboards or V-drives would have the strainer. The holes in the drive pickup act "sort of" as a strainer. If you're itching to do something, I would install a block-off plate for the drive, then install a thru-hull with seacock and strainer.

 

[Cap10patNC]

I have a 1980 26 Weekender - almost the same. The water pickup is a thru-hull just in front of my engine on the port side. The hull was manufactured with a similar hole drilled on the opposite side, but, having a single engine it was never used. I don't have any additional seawater filter - although that may be an idea. However, I do have a closed cooling system and a heat exchanger bolted to the front of the engine. That may be how your boat, or the one you are servicing, was made - with fresh water cooling. That engine is probably a replacement and the fresh water cooling was not replaced. They just turned it into an open cooling system. Without the additional strainer my raw water just flows through the heat exchanger, then to the exhaust elbows. Works great. Searay may not have made the thru-hull water pickup holes if the boat wasn't getting fresh water cooling.
These setups - yours or mine are supposed to have water pumps in the sterndrive and then dump the water without entering the boat. On land you have to be sure to supply water to both inputs and pumps. And you have to make sure service people do that too. Especially important if you have a Bravo drive.

 

[hpcrank]

Cap10patNC

Thanks for the reply. My out drive is pre-Alpha and does not have any water pick up openings. It has a raw water attached to the engine and a conventional water circulating pump on the engine. I have been told that the early 7.4's with the engine mounted raw water pumps do not have out drive water inlets. I have searched the out drive unit multiple times and can find no inlets either small holes or slits or grill.My out drive has the lifting hook on top and is referred to as an "O" drive.

I have not started the boat since buying it. When I bought the boat the owner started it and had a hose to the engine via the raw water pick up hose and nothing else. I do have another raw water pick up that serves the AC generator.

Hpcrank

 

[Lazy Daze]

Hmmm. I must had misread what you wrote - I took "My boat has a raw water pick up thru the engine bay hull" to mean it went through the transom to the outdrive. I have no experience with an "O" drive - in fact, I've never even heard of it!

But... if "My boat has a raw water pick up thru the engine bay hull" is true, then it sounds like you do have a thru-hull intake already there? But you just don't have a strainer? Is that right?

When the owner started the boat for you, was the garden hose just shoved into a hose from the engine? Did he bypass the raw water pump/impeller? I'm not clear on this from what you wrote.

 

[Cap10patNC]

Yeah, I'm still running an outdrive with a lifting hook on the top. As I said, its a 1980. It too is a pre-Alpha.

My engine is the 5.7, where you have the 7.4. Today that would have a Bravo drive on it. The Alpha was never designed for 7.4 L engines.
I recall they had some heavier outdrives very briefly, I forget the name, they may have had the lifting hook. They probably became the Bravo. You might have an Alpha outdrive with a 7.4L engine, which could be a problem. I'll look around a little further. Any chance you can find a serial number on the outdrive?

 

[hpcrank]

Dennis

Thanks for your response.

Your assumption that the raw water pick up thru hull (and sea cock) is already there is correct but there is no strainer. The owner had a hose fitting rigged up to fit into the sea/raw water hose which was disconnected from the thru hull sea cock. The hose fed into the raw water pump hose which in turn feeds thru the raw water pump then into the engine water circulating pump.

The out drive has no water inlet. I have replaced all the water hoses so I installed a valve in the raw water pick up hose that is connected to a female hose fitting so in the future I will not have to disconnect any hoses, just close the raw water sea cock, connect the garden hose and open my new valve. I would like to know if a strainer should be used on a fresh water boat. There is no evidence of any previous one.

Thanks
Hpcrank

 

[hpcrank]

Cap10patNC

Thanks for your response.

According to my Mercruiser Clymer Stern Drive Shop Manual (1964-1988) pre Alpha stern drive models were Model O, Model I, Model II transom and non transom, Models II-TR, II-TRS, III and 215 H and 215-E. TR and TRS models were used in the 1986 and 1987 boats.

My stern drive unit is serial #5887755-1-50R or the 88 part might be 33 as it is hardly legible.

Thanks
Hpcrank

 

[Lazy Daze]

Crank, yes, I would advise installing a strainer. I can't think of any downside (other than initial cost) to having it, yet without you run the possibility of sucking stuff (weeds, floating debris etc) into the engine. I wouldn't necessarily put salt vs fresh on the table as a factor to consider. Granted, if you have a grate-style thru-hull intake that will help and soft things would likely get chewed up by the impeller, but some stuff can also pass through and clog somewhere else.

I'm only mentioning the following as a "just in case" question... When you installed the new valve and fittings... are they bronze or Marelon? Double clamp everything (worm gears on opposite side)? All hose leading to the raw water pump is wire-reinforced?