Inlet Suction Hoses for Raw Water Pump

[Viper]

The 180 assembly isn't necessary. You should be able to accomplish what you want with just a hose alone. Have the 90 on the seacock point in a direction that allows you to take a path with the hose that will allow a proper run even if it's along the opposite side of the engine underneath then around the back and over to the pump. I've never seen the need to install any other plumbing hardware in this circuit, keep it simple except for a strainer if you so choose. The hose can probably accommodate a tighter radius than you think.

Many older vessels didn't come with strainers from factory, was an option at one time but like most things transition from option to standard equipment for one reason or another. Also comes down to production cost savings. I don't know of any downside to installing strainers. This is a boat manufacturer feature not an engine one unless you talking some Volvo diesel models that have them on the engines themselves.

Use a "marine" rated wire wound wet exhaust/water hose. Anything else is likely to show up on your next survey unless the surveyor is familiar with the spec of another hose you decide to install and deems it suitable for marine use.

[km1125]

When you're buying the fittings, make sure you look for a 'sweep' 90. There are two types available... a 'hard' 90 and a 'sweep' 90. The sweep 90 takes up a little more room, but doesn't impact flow though it much at all, vs a 'hard' 90 that can impact it quite a bit.

Definitely agree with the marine wire-wound hose.... it will not collapse and will take a very tight bend without kinking.

[Viper]

Source of the post When you're buying the fittings, make sure you look for a 'sweep' 90.....

++1
Specifically designed for this type of application.
https://www.greatlakesskipper.com/perko-63-7-brass-1-1-4-inch-90-degree-boat-pipe-to-hose-adapter

[bud37]

Eggbert are you on salt water ?

[Eggbert]

My goodness, but these internet forums are great. That’s because of people like you who want to help. Thank-you all very much.

So far, with all this brainstorming, I am definitely sticking with a single hose and no hardware at the 180. I havn’t completely identified which hose, and although the PCV seems much better than I expected, the common inlet/exhaust suction hose (with wire) is available locally and seems to be the Shields 250 series. I havn’t found a bend radius spec yet, but some websites say good for tight bends and others say a “gentle” radius. No doubt I will have to get some in my hands to try.

https://www.go2marine.com/product/16460 ... -foot.html

As far as the 90 degree fitting for the seacock, I was aware of the different radius fittings, but thought I saw them with different names than “sweep” and “hard”. Can’t find it now, but the term “shallow” comes to mind. That Perko unit looks perfect. Thank-you km1125 and Viper.

Yes bud37, I am on salt water. Note the Perko unit is brass vs. bronze however I think it should last a long time anyway. It’s in sight and I get to check it every time I disconnect the hose to flush the engine for winter.

On the strainer, the only one there now is the slotted bronze one, the same as in the picture in my first post. Small debris will get past it. My old raw water pump impellor did die (as seen below) but I suspect more from age than small bits and pieces. I am using a heat exchanger, so there’s not a lot of places for debris to build up such as the engine block, manifolds, etc.



Mind you a strainer sounds like a good idea as long as there is easy access to it. It might plug during use and would need to be quickly cleaned. I’m a little worried I won’t have room. Even the “soft” 90 fitting might have the hose close to the engine harmonic balancer (crank pulley) and that’s the only easy access place I can think of at this moment.

Thank-you again. I appreciate and value all your thoughts and opinions.

[bud37]

Source of the post Yes bud37, I am on salt water. Note the Perko unit is brass vs. bronze however I think it should last a long time anyway. It’s in sight and I get to check it every time I disconnect the hose to flush the engine for winter.

Just to note, a visual of a brass fitting in a salt water environment may not tell what is going on as the brass could be failing inside out and will look brand new on the outside until it fails..... ...bad fitting to fail....anyhow I have an idea you already know this....

[Eggbert]

Source of the post Just to note, a visual of a brass fitting in a salt water environment may not tell what is going on as the brass could be failing inside out and will look brand new on the outside until it fails..... ...bad fitting to fail....anyhow I have an idea you already know this....

Well… er…. I’m not sure. If you mean the inside surface of the brass will corrode before the outside surface due to the salt water passing through, then “yes”. If you mean the brass will deteriorate under the surface of the metal, then “no”.

It doesn’t appear to be a problem though as I have now identified two different sources for a bronze 90. Not referred to as a “sweep” 90, one is called a 90 Long Radius Insert Adapter and the other a 90 Smooth Flow Insert Adapter. All different names for the same thing I guess.

So the problem of finding a bronze 90 appears to be solved, if I have room to screw it in. I think I do. See below (and yes, I know I need to remove the rust from the pulleys or I may chew through a belt or two, but for a 1985 boat used in salt water, it‘s not terribly bad):



You can see how the hose goes back under the engine. It turns and connects to the back of the water pump which is on the left.

All that seems left is to identify hose. I measured and have 20” between stringers, so I ought to be able to determine if a certain hose will work by bending it at the Marine Supply place (if they have some in stock) as I can’t find the bend radius of most hoses I’ve looked at.

[bud37]

I am willing to go out on a limb here and say given that pic and your dimensions you will have no problem getting the hose to bend to fit......just go off the sea cock straight back and loop around.

Regarding the brass, its both.....gives up the zinc.

[km1125]

I just checked my raw water hose. I have a 1 1/4" hose and it bends 180" within about 12" from the seacock to the raw water pump.

[vineyardgray]

Source of the post I question the addition of sea strainers in the raw water supply to the engines? There must have been a reason Carver and the engine manufactures never installed them when the boats were built?

I read through the 1988 "large boat" manual from carver and it says (I'm paraphrasing) that the strainers provided are exterior and under certain circumstances the owner may want to (or need to for the purpose of meeting regulation) add additional strainers to the exterior units. So it doesn't look like they felt like the expense of strainers onboard was necessary, but left it up to the end user to determine.