Changed impeller and running a little warm

So I changed the impeller on my 1996 Sanger v210 with about 315 hours, and the boat now seems to run a little warm. The temp gauge doesn't have any numbers just notches between the C and H. The temp seems to hover around the last notch before the H and runs a little cooler when driving the boat around (it does not go into the H area when driving around). I have also went through the following thread and did what people suggested http://www.wakeworld.com/MB/Discus/messages/3183/717597.html?1248112410. This is a list of what i checked tonight:
-Since old impeller was destroyed i checked the tranny cooler screen and cleaned out several old impeller bits
- we pulled the hoses at the thermostat housing to check for any debris and blockages. None found.
-We ran the boat for a quick second with the various hoses pulled at the thermostat housing to make sure water flowing and to test how strong the flow of water was. Seemed to be coming out at a fairly good pace.

As it stands the boat is usable as we did some wakeboard sessions and ran it at a speed that we would for surfing and the needle did not go into the H area, I'm just confused as to why it would be running warm now. we tried to pull the hoses off the V-drive but they were on there pretty good and since water was coming out of the hoses at the thermostat housing we figured there couldn't be a blockage in there. I'm going to pull the impeller tomorrow and double check how it was installed and the condition of the new one.

any other suggestions out there?

Water flows up through the thermostat so debris can get caught behind it. You have to remove the thermostat housing and thermostat to look for debris behind it. Make sure to flush motor well with thermostat removed little chunks of rubber that can easily clog a thermostat can hide anywhere in the water jacket of the block, heads or intake. While you have the thermostat removed replace it with a new on and gasket. Should be a Chevy SB thermostat and gasket, just a 160 temp.

We pulled the thermostat housing off when we were on the water and changed the gasket as we noticed water coming out of the housing. While we had the housing apart we actually pulled the thermostat out and ran the boat for a bit to see if in fact the thermostat was the issue but the same warmer temps were being shown. Could there still be bits and debris in there after pulling the thermostat right out and if so what is the best way to flush the motor? Can i hook up a garden hose to one of the hoses and if so which would be the best?

debris can get caught in the lines before the water pump and after. I recently had this issue and pulled all the hoses and flushed them out. Mine now runs at a constant 142 degrees like the thermostat is rated for.

Hey Kevin, did you just pop the hoses off and pump water from a garden hose through them?

First check with boat running at speed and see the volume of water being pumpes out the back. Then replace thermostat, they are not too expensive. By the way if that has the Jabsco 3 peice cold water pump, it is really easy to install housing or gaskets 1/4 turn off. I did this the first time I changed it and it overheated instantly. Also check the water pump on the engine for flow. The hoses should be rock hard when flowing water but an obstruction will cause that also. also check the screen on the bottom of the boat for debris obstruction.
Rick

If the impeller was smoked, there is a chance that you damaged the housing itself. If you have the composite pump, you may need to replace the center housing section.

thanks for the responses guys. Today i pulled the new impeller out of the housing just to double check if the new one was toast or not. The housing in the boat in the two piece housing that has a couple metal plates and several gaskets. After inspecting the housing i noticed a couple things.
-a few of the bolt holes on the housing were cracked (the part where the bolt head gets tightened to)
-the metal plates seemed to be a bit warped and bent

Could the housing not be sealing properly due to the bolts not being able to be tightened down completely and air getting into the system? The metal plates being a bit warped could be affecting the operation as well?

Today i went down to a local mercruiser dealer and discovered that there is a replacement unit for the 2 piece unit that i have. This unit is a one piece unit that eliminates all the various gaskets and plates. I should have it tomorrow to install and will be taking the boat out for a test run in the next couple days and will post my results

Good call Jason on the replacement pump. They are pricey but worth it. The metal plates in your old pump were never flat to begin with they allow end play to the impeller. It takes 3 gaskets 2 paper and one compression gasket to seal the 3 peice unit. It sounds like it was put together wrong possibly. Make sure belt is tight when installed and hoses are installed correctly. I would force water backwards from pump out the bottom of the hull to make sure through hull is clear. Also check that thermostat. Remove hoses from thermostat and force water backwards. I haave the orignal Sanger manual and can email you the water flow diagram if you PM me.
Rick

the new design brass housing is bullit proof, and future changes will be a breeze, just the impeller and an o ring. Good move.

PROBLEM SOLVED!! so after changing out the old impeller housing with the new 2 piece housing and test driving the boat it was still running a little warm. We pulled some hoses and flushed them out and still running warm. I decided to pull all the hoses off the thermostat housing and check inside the housing for a blockage. What did i find when i looked inside the housing? TWO THERMOSTATS. When the thermostat was changed the old one was never located before the new one was installed. The new one was dropped into the block and we never realized that the thermostat sits inside the housing with a plastic sleeve around it. moral of the story is locate your old parts before putting the new parts in