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Missing Thermostat ??


SkySkiMalibuGeof

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Great website, just found it tonight. I haven't had much trouble with my 97 Echelon, 320 Monsoon Engine.

This winter the temp wouldn't get above 120, and it has always run around 140-150. I replaced the temp sending unit, which is pointed out in the picture attached.

I was going to replace the thermostat to see if that would fix it. I'm not mechanically inclined so people have to walk me through this sort of stuff. My buddy told me where the thermostat should be, but when I pulled the casing off, nothing was there? Can someone tell me if I'm looking in the correct spot? If so, why would it be missing? I bought the boat in 2002 with 450 hours. It now has 1987 hours (should hit 2000 this weekend). I've changed the impeller a couple of times, replaced a fuel pump, had a couple of tune ups, but other than that, no problems, especially not with overheating.

Can I get a thermostat at an autopart store and what kind/part number?

Thanks

Geof

www.skyski.com

www.heliumwake.com

www.foilfreaks.com

www.dallaswakeboarding.com

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Hey Geof, Welcome to the site. It sure looks like a thermostat should go in there. Maybe that's why it's not getting to temp? Someone with that age boat will chime in before too long.

To post pictures click here.

The other way is to link them here from another site. This way we don't have to host the picture and take up the extra ($) bandwidth.

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Yes, the thermostat should be in hole # 1.

Why is it not there? Dontknow.gif I don't know.

It's possible that the previous owner was out on the water, the old one froze up causing the engine to overheat so he pulled it out to finish the day (week-end...whatever). You say it used to run 140-150...was the water warmer then than it is now? Colder intake water flowing unrestricted through the block would make your engine run cold.

Thermostat at Skidim

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Thanks, I'll order one today.

I've had the boat since 2002, but this is the first time it's run cold over an extended period. We always ride in the winter, water about 43. Maybe this is the first year I've paid attention to it?

The water is finally starting to warm up, it's in the low 60's now.

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Well, DIM said it should be under #2, not #1, so I'll have to open up #2 tonight and look.
:Doh: Sorry for the misdirection. Glad you call Skidim. Thumbup.gif They're awesome.

I've never seen that triangular piece before. :unsure: But then I've never worked on an 80's era Indmar engine either so... :blush: Sorry.

Keep us posted...I'm curious. :)

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I'm thinking the stat should be in #1. I can't tell much about the water flow from that zoomed in pic. But it looks similar to my '01 monsoon setup. Anyway, #2 should be an empty bypass block. Again, guessing from your pic, the large hose you have disconnected at the top is water coming in from the raw water pump? And the large hose still connected is the inlet water for the engine cooling pump? And then the two smaller hoses go to the exhaust manifolds? If so, there should not be a stat in #2. The flow should be raw pump to bypass block, and then from the block it goes out to the exhaust manifolds and into the engine cooling pump. With a cold engine (closed stat), there will be no flow through the engine. All of the incoming water bypasses to the manifolds and out the exhaust. As the engine comes to temp and the stat opens, the engine cooling pump then pushes water into the front of the block, and it exits the engine through the stat, to the bypass block, and out through the manifolds. With a stat in #2 I would think there would be no way for incoming water to exit through the exhaust until the stat opens. I'm almost certain this is correct. I'm not sure why skidim would say it's in #2.

As a side note, what it the wire lead going to on top of the bypass block?

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I'm thinking the stat should be in #1. I can't tell much about the water flow from that zoomed in pic. But it looks similar to my '01 monsoon setup. Anyway, #2 should be an empty bypass block. Again, guessing from your pic, the large hose you have disconnected at the top is water coming in from the raw water pump? And the large hose still connected is the inlet water for the engine cooling pump? And then the two smaller hoses go to the exhaust manifolds? If so, there should not be a stat in #2. The flow should be raw pump to bypass block, and then from the block it goes out to the exhaust manifolds and into the engine cooling pump. With a cold engine (closed stat), there will be no flow through the engine. All of the incoming water bypasses to the manifolds and out the exhaust. As the engine comes to temp and the stat opens, the engine cooling pump then pushes water into the front of the block, and it exits the engine through the stat, to the bypass block, and out through the manifolds. With a stat in #2 I would think there would be no way for incoming water to exit through the exhaust until the stat opens. I'm almost certain this is correct. I'm not sure why skidim would say it's in #2.

As a side note, what it the wire lead going to on top of the bypass block?

I'm surprised as well. I am in agreement as above.

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3rd vote that assumes it would be in the manifold location (1). Is it not stuck to the housing you have removed?

Peter

nope

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Yes, the thermostat should be in hole # 1.
DIM said it should be under #2, not #1,...
I'm thinking the stat should be in #1...
I'm surprised as well. I am in agreement as above.
3rd vote that assumes it would be in the manifold location (1)...
Well, if nothing else, I don't feel so bad about thinking it should be in #1. :lol:.....:Doh:
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The newer boats have that triangle shaped housing over your hole #1. If you look at the triangle housing you see the dividing line is below the manifold hoses. If the theromstat is in there, everything still works.

-Chris

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This post is freakin me out every time I look at it. Everything I know tells me to put the t-stat right there in #1...I can see the recessed area that it belongs in but if you look at this page in the skidim manual, they do have some triangular gaskets that look like it may go in #2. I don't care if it's in #2 I'm still putting it in #1. Whistling.gif

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This post is freakin me out every time I look at it. Everything I know tells me to put the t-stat right there in #1...I can see the recessed area that it belongs in but if you look at this page in the skidim manual, they do have some triangular gaskets that look like it may go in #2. I don't care if it's in #2 I'm still putting it in #1. Whistling.gif

There are two gaskets on the newer monsoons. My 01 has one of the "baseball diamond" gaskets (0731) in the bypass block. The bypass block is split in half. So there should be intake, stat, stat gasket (0739), lower bypass, gasket (0731), upper bypass. It looks like the OP might need the 0709 gasket in the bypass block.

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Well, I stand corrected. But now seeing the inside of the triangle....that hole in front of the stat helps explain what I didn't understand before - how water gets through in the case the stat is closed.

But am I the only crazy one looking at both pics that it looks like the stat would function the same whether it was in #1 or #2, because there is really nothing between the two holes. Oh well, Indmar's got people smarter than me doing this so it must be right. Hope your problem got fixed.

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Boat ran fine tonight, temp is back between 160-180. 1993 hours after tonight, should hit 2000 this weekend!

Thanks for everyone's comments.

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