View Full Version : Hot Water Shower and the LY6 Engine

03-05-2009, 11:39 PM
Hello to all...

I just recently purchased a 40th Prostar 197 with the LY6 Engine.

The dealer ordered it with everything but the hot water shower, something we have become quite accustomed to having.

Question is does anyone have an LY6 with the shower installed? Like where does the pump go and the like, and where do you hook in the hoses? The Malibu Response with the Black Scorpion had plenty of hoses for the cold water return. The LY6 has just a few huge hoses in the front.

They install them from the factory and the dealer I deal with hasn't seen one yet in person so I figure I would go to the source which is you experienced MC owners.

Pictures would be great also!!



03-06-2009, 01:27 PM
Congrats on the boat purchase. Sounds like a good combo, LY6 with the 197.

Any pics?


03-06-2009, 01:37 PM
The cold water will be taken from a Tee placed after the raw water pump. The hot water will be taken from a tee in the line going to the heater (granted you have a heater). If you do not have a heater, the hot water will be taken from the block near the thermostat housing.

Pic if you have a heater.


The electric pump and valves are located in the ski locker at the stern of the boat.

03-06-2009, 05:03 PM

Do you have an MCX engine in your 2007?

The 2008 LY6 is totally different. I just brought it home yesterday, and I will do my best to get pictures of the front of the engine so you can look at them.

It does have a heater so I think the hot water side is ok. Either they cut the 5/8's line a shade short and put an extension on or the brass fitting and clamps about 7 inches from the engine is where the hot water tap goes for the hot water shower.

The cold water stuff is a shade trickier as it is all 1 1/4 hard wall up to where the box is that all the hoses connect to.

I kept telling the dealer (jokingly sort of) that people would rather have the shower than those crazy led lights that cost a mint underneath the deck. While we here in central Illinois have a nuclear power plant heated lake, the beginning and end of the season can still be a might bit chilly!!!

Thanks...pics to come...


The cold water will be taken from a Tee placed after the raw water pump. The hot water will be taken from a tee in the line going to the heater (granted you have a heater). If you do not have a heater, the hot water will be taken from the block near the thermostat housing.

Pic if you have a heater.


The electric pump and valves are located in the ski locker at the stern of the boat.

03-06-2009, 05:08 PM
I guess I should have asked about the mounting of the pump and valve. He said it went in the back but where actually I'm not sure. It appears most 190's and 197's look the same under the covers in the back. If not to much trouble, do you have a pic of that also? I asssume the wiring is back there hidden somewhere also?

Sorry about not asking this in the previous post...


Holman J.B.F
03-06-2009, 05:59 PM


The LY6 has a reverse flow cooling system where water enters the engine through the thermostat instead of leaving through the thermostat. Unfortunately, this cooling system does not produce much heat in the heater circuit in it's standard raw water cooled configuration.
(by L. Engelbert)

Holman J.B.F
03-06-2009, 06:04 PM
Oopps big pics,sorry
here are 3 more.


Holman J.B.F
03-06-2009, 06:07 PM

Holman J.B.F
03-06-2009, 06:35 PM
I messed it up in my previous post,..sorry.
Anyway,.Here is what i did and it works,more heat.
p.s leave the U tube as it is.

(test at own risk)

03-07-2009, 01:47 PM

Very nice picture array there. Much appreciated! Hopefully I won't have to take mine apart anytime soon...lol

The heater seemed to work ok when we demo'ed it last summer. Your idea if we are heat starved when it gets frosty here will be implemented asap.

I have attached 2 pictures for possible points on the hot water shower setup unless of course someone has the LY6 and pictures of the factory original. The dealer is on vacation and like I said he has never seen one in person. I have done heaters in previous boats so it shouldn't be to much of a problem...assuming I can find the right exit points for the hot and cold water.

I looked at it again late last night and maybe another option is taking hot water from the block (the LY6 has a 6 inch stub rubber hose like the oil drain hose on each side). I looked in the back and still can't picture where the pump would mount even though the dealer did point out it went behind the carpeted panel. I assume the valves could be mounted in the engine area???

Thanks to everyone helping me figure this out!!!


Holman J.B.F
03-07-2009, 03:49 PM
You will use your shower when the engine idles ,i,m not sure if you,ll have enough flow.(unless the shower pump is self priming)

the cold water spot you indicated is ok.
Strange thing about the LY6 is that both aux waterlines are behind the stat and are connected see the flashlight pic..The squished hose is the send(hot water return).I would try that one.

maybe you can find some more info there.

03-07-2009, 04:14 PM
The shower has a pump (Aquatik) and I believe it is self priming. At least it worked that way in the Malibu Response we had.

The "squished hose" (need to get another 90 degree bend unless it's designed to be squished which I doubt) you mentioned is the send or the return? I took it as "send" sent the water to the heater but then you mentioned "return".

I could always clamp on at the winterizing port which is an oil change hose but shortened to 6 inches.

I noticed the flashlight and light coming out of both holes. How can there be flow from one and a return from the other if the light shines through???

Another concern I have and this is not relevant to the heater, but as a MC enthusiast you might have a comment.

I noticed when I took the floor mat (huge and heavy) out and was kneeling on the floor about a foot and a half behind the drivers seat, I heard a slight crackling noise and noticed the floor compressed about an 1/8 of an inch in about a 5 inch circle. It lines up directed behind the pylon and starts at the board that holds skis in to about 6 to 8 inches back to the engine cover. I have read other threads here about them drilling 3 inch holes times about 5 on each side to inject flotaion foam. The Malibu we had had square holes cut and then reglassed for their foam injection ports. The observers side is slightly raised in that area but not objectionable and it kind of creaks a little when I put the heel of my foot along the board from front to back. I am 6 ft something and around 230 pounds so I guess a heel would be quite abit of load in a few square inches. Otherwise the rest of the floor feels like concrete for the most part.

Any thoughts???

Thanks for the quick replies!!


03-07-2009, 09:08 PM
Here's a previous thread with a pdf file showing the MC shower install; a MCX engine, but also shows where the pump and control panel are located; believe the back storage areas are similiar for last few years of PS197s; and yes, the shower wires for the pump are already there (at least in the 2005 PS197)...


Also, some pics of the shower panel and pump location in my 2005 PS197...

03-07-2009, 10:04 PM

Thanks for the pictures. Now it it makes sense where things go. Pictures really are worth a thousand words!!!


I looked at my 2006 Tahoe with the 5.3 engine and it has the same contraption as the LY6 does for the thermostat housing etc.

The left one in the truck, which is the squished one in the boat, is the hot water to the heater. The right one is the return. I assume the boat mirrors the truck in this sense.

Thanks for everyones help!!


Holman J.B.F
03-08-2009, 04:16 AM
yes but that,s a closed cooling system and a different thermostat housing., there are about 20 Mc,s at my shop i,ll have a peak inside and see if i can find a LY6 with a shower.I,m not a dealer.just a gelcoat repair guy.

P.s what i ment with send as send to shower.Hot water from the engine is comming out of that smaller hole.

03-08-2009, 01:05 PM
Good point on the closed cooling system in the truck....

So basically the hot water is coming out of the engine from the left hole (the one closest to the engine or in the case of my picture, the one with the squished hose)?

If there weren't tornado watchs and high winds today (you have to love the weather change in Illinois!) I would take it to the lake and try it out...

Summer can't come soon enough for us!!!!!


Holman J.B.F
03-08-2009, 02:30 PM
Yes,...just T the hot water suply for the shower in that squished hose and try it out.(but i guess it will be overheating during a long period of use of the shower)Unless the stat is wide open,but on idle it might be closed.
P.s there are no LY6 with showers at my shop.Never seen any to my knowledge iirc they didn,t install showers on a LY6.

03-08-2009, 03:30 PM
I just looked again at one of your previous pictures. It was on the right side of the picture (the one with the grey heater box and red and orange lines) and I didn't notice it until now. It appears you send the water from the heater that goes back to the engine and splice that into the cold water intake line?? Then the hot water that goes to the heater is T'ed into the large hose that comes from the top of the engine.

I take it the idea of putting a suction pressure on the return side of the heater to draw the hot water from the engine through the heater should in theory improve the flow of hot water through the heater???

When we use the shower it is probably used about 1 minute or less to fill wetsuits with warm water. In the old days we didn't have hot water showers and heaters. It's one of those convenience features but we probably wouldn't die if we didn't have it. It's a challenge now to see if we can get it done and make it work right...Lifes full of challenges heh???

Much appreciated!!


03-08-2009, 04:30 PM
Marc I take it you boat on clinton lake? Every come up north at all? Looks as though there are a few members that hit up the clinton lake area

03-08-2009, 05:20 PM
Yes, Clinton lake...about 30 miles to the marina.

Haven't done to much boating the last 4 years. Having a 5 year old daughter can keep a person ultra busy, however this year she has taken a serious interest in the "lake". So...traded in the Bu for a MC.

She has a 109cm Hyperlite wakeboard which she thinks she is going to be able to do...lol

The good thing is it is from 40 pounds to 90 pounds capable and she is 41 pounds now. Something to grow into. I think the kneeboard is more her speed but I learned along time ago not ot argue with women!!

So you close by???


03-08-2009, 06:35 PM
bout 2 hours north. Elgin