Tell me this is the way it works! - Maxum Boat Owners Club

donald · 10-10-2016, 02:49 AM

Hi All!
I have a 95 Maxum 2400 scr with a 5.7l Alpha 1 Gen 2 that has a engine only closed cooling system. The temp is between 160 to 170 at the tstat and 170 to 180 at the elbows using I R gun.
Both of the cooling line to the elbows are routed from the HE after the raw water has cooled the engine!
My question is does this sound correct?
That is the way the instructions say to plumb it!
It was installed on the boat when I bought it!
First time owning a fresh water cooled engine!
Thanks to all!
Don

mmwjr · 10-10-2016, 11:17 AM

Don is the closed cooling system a full (engine and exhaust manifolds) or partial (engine only)?

In a full system the closed system will have a supply and return hose to each exhaust manifold and a raw water hoses to the elbows. Block off gaskets are used between the manifold and elbow.

In a partial system the raw water hoses should go to the bottom of the exhaust manifolds. Standard open gaskets are used between the manifold and elbow.

donald · 10-10-2016, 02:49 PM

Hi Mike!
Thanks for the reply!
It's a partial system! It does not have a raw water pump at the engine!
This is all new to me, so I am just trying to find out if this thing is functioning properly!
Or if I should just remove it and go back to a sea water system!
I do like the idea that I do not have to drain the whole system to winterize it, that and the fact that the boat has a cabin heater in it as we do a lot of boating in the late Fall and early Spring!
Thank Again!
Don

speedysprocket · 10-10-2016, 02:55 PM

The sea water pump is in your Alpha drive. Fresh water cooled is the way to go. Engine will last longer with less cooling system related troubles.

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donald · 10-10-2016, 03:26 PM

Hi Speedy!
That is what I was thinking, but like I said this is new to me!
Just trying to see if the temps are close to what they should be or if something is wrong!
I am familiar with open systems, just not a closed system!
Thanks Again!
Don

mmwjr · 10-10-2016, 04:13 PM

Don as stated the raw water pump is in the drive and provides sea water to the heat exchanger to remove engine heat just like air does when passing through a car radiator.

It sounds like the exhaust is not set up correctly for a partial system should have the raw water going to the manifolds and not the elbows which is why the temps are too high. Can you post some pictures? Also do you have a brand and model number of the closed cooling system?

I would keep the system but get it set up correctly which should not take much.

donald · 10-11-2016, 06:42 PM

Hi mmwjr
I have the installation instructions and the diagram for the system and it shows the cooling lines going to the bottom of the manifolds and the elbows pluged! That is the way it is plumbed!
I do not think that the system is factory as the Merc. manual shows a raw water pump on the engine!
Just seems strange that the manifolds get water that is already hot from the HE!
Thanks for the reply!
Don

speedysprocket · 10-11-2016, 07:32 PM

That's how is works. The water coming out of the heat exchanger isn't as hot as you might think. In a raw water cooled engine, that used water goes into the manifolds and elbows, too.

mmwjr · 10-11-2016, 10:07 PM

Quote:

Originally Posted by donald

Hi mmwjr
I have the installation instructions and the diagram for the system and it shows the cooling lines going to the bottom of the manifolds and the elbows pluged! That is the way it is plumbed!
I do not think that the system is factory as the Merc. manual shows a raw water pump on the engine!
Just seems strange that the manifolds get water that is already hot from the HE!
Thanks for the reply!
Don

Hey Don call me Mike

In post one you said the hoses went to the elbows not the manifolds. The Merc manual is for a Bravo drive as that do not offer a HE for the Alpha yet it's availble in aftermarket. What brand is the system?

From the last post it sounds right but the exhaust temps are high IMO.

Can you post some pictures of the set up?

donald · 10-12-2016, 12:04 AM

Sorry Mike!
I guess my fingers and my brain are not fully connected also!
Should have said to the manifolds!
I don't know the brand as the paperwork I have does not have a name or logo on it!
Nothing on the HE either!
Thanks
Just call me mr. Dumb Fingers!
Don

speedysprocket · 10-12-2016, 12:10 AM

The end caps might have the manufacture cast into them. One of mine is like that. The brass end caps say Lenco, which is the company that made it.

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mmwjr · 10-12-2016, 12:34 AM

Some pics might help me identify the manufacture.

What is the temp of the hoses going to the bottom of the manifolds?

donald · 10-12-2016, 03:32 AM

Hi All
I will look next week and try to get pics and send them.
Lots of things happening this weekend, so will have to wait until Monday or Tuesday to look and see what I see!
Thanks Speedy nad Mike!
Don

donald · 10-22-2016, 03:12 PM

OK! I am back!
Sorry to take so long to reply, we had a hell of a storm here!
OK a little history on the boat!
It's a 1995 2400SCR with a 5.7 half cooling system Alpha 1 Gen 2 drive.
I bought the boat and trailer mid summer and had it all cked out prior to purchase,
everything cked OK only a few miner problems so OK there.
I was not able to see boat before purchase or water test it as it was in another state!
First probem occured when the transport driver delivered the boat, NO Brakes on trailer!!! Long story short That has been repaired!
Now as the temps are dropping here (mid to low 30s) so I drained the raw water from the engine and got a good amount out of the port side manifold, not so much from starboard side!
Pulled the plug on HE and no water!!
So my added questions!
1/ Could the water drain back out of the system while on a trailer? ( Drive in full down postion!)
2/ I have not had the boat in the water as the trailer repair took longer than I expected, only have ran boat on muffs. Could it be running warm because of that? We only have about 25 psi water pressure at the house!
3/ Could it have a bad lower unit water pump impeller and the low water pressure at the house be part or all of the cooling problem?
It was supposed to have a new impeller in the drive!
Sorry this has drawn out so long but we live in the middle of desaster area here, my priorities have been devided
Thanks to all for helping !
Sorry tried to post pics but all my pics are to large to upload!
Thanks!
Don

mmwjr · 10-22-2016, 03:38 PM

When you drained the exhaust the plug is lower than the HE so it drained down as well. I do not think the water pressure at the house is an issue as when the boat is sitting in water no pressure is applied at rest so as long as you are only running at idle no overheating should occur.

You can remove the raw water hose going to the HE from the transom assy to see how much water flow there is. If I recall the engine temp was ok it was just the exhaust components that are hot. I would focus on the exhaust water flow.

donald · 10-22-2016, 04:29 PM

Hi Mike!
I did not find a plug in the elbows so I pulled the hoses of of the manifolds!
I was not able to remove the hose from the P.S. cooler as it is behind a motor mount! 2400 SCR's have a very tight engine bay! ( As there is no room there!)
Other than it running at what they say is to hot for the elbows it runs just fine! Starts a little hard the fist time after sitting for several days.
Boat had new or rebuilt engine installed in 2000, only thing I can find on the engine problem was that it would not start, no other diag. They just replaced engine and it was covered by an extended Warr.
Clock shows 300 HRS.!
I am the third owner so don't think I can get muck more info on it!
Thanks to all!
Don

mmwjr · 10-22-2016, 10:44 PM

300 hours on the endings sine 2000 is less that 20 per year which is below the norm. Sounds like a clean enough boat for her age. I have a 1997 2400 SCR so I understand how tight things can be in the engine compartment. Open but you need to bend 180 over to reach anything.

Pulling the hose will do the job for the manifolds.

donald · 10-23-2016, 01:12 AM

Hi Mike!
Bend over 180 Deg?
If I do that at my age I would need 911 on speed dial! I would be there until they cut the deck out above me!
I was thinking of just cutting the hose before the P.S. cooler and putting a pipe in with a drain valve for ease of future draining! Probably wont get all of the water out but it would be better then being trapped in the bilge until I die!
Tanks Again for all the help!
Don

mmwjr · 10-23-2016, 02:58 AM

Hey Don tell me about it, I have a ruptured disk so working in the engine compartment can be rather painful.

donald · 10-23-2016, 05:15 AM

Hi Mike!
I know what you are sating I have 3 bulging disks and 2 bad knees!
The golden years are great!!!!!
Don