Best way to figure out why GT-40 is overheating?

[cal1319]

Trying to go step wise through figuring out why the boat is overheating. I have gone through numerous posts on this forum ( great site btw!) and think I have a plan.
Background story. Purchased a used 01 SAN with around 500hrs on it. Took it to the lake this last weekend to see whats what with the boat. Started right up, however noticed the exhaust was heating up real fast, check engine light was on (before the temperature rose to 200). Idled for a few minutes wanted to see if the engine would cool itself, once it passed 160 and saw the exhaust really warm up, I knew the impellor was shot. Pulled the RWP and sure enough there was nothing left, wish I took a picture to show you guys! So swapped the impellor, cleared the strainer back in the water. Started right up sounded great this time. Looked for water leaks didn’t see anything so just putted around 1K rpm for a few minutes temp stayed around 160ish, tried to get it up to speed temp shot up to 180 then 200, I pulled off the throttle before the boat went into limp mode. Idled back to the dock temp slowly went back down. Went home, pulled the tstat out and it has seen better days. Ordered new one comes in tomorrow. In the meantime what is the best course of action to check other possibilities for why it is still overheating? I want to flush the transmission cooler as many posts say things can get stuck there. Should I pull the risers to check those as well? The strainer has its O-ring and its fairly tight, but will check once Tstat is back in if I can see any air in there. Will tighten all hoses. When I took the RWP off I cleaned all the housing and such, used both the o ring and gasket. The Tstat housing was rusted pretty bad, cleaned that up and had to scrap the old gasket off and cleaned up the lower housing as well. Is there anything else you guys would recommend in checking out? I did put a garden hose in each of the hoses leading to the exhaust and they seemed to drain out fine, there was no restriction in flow on either side. Thanks for any suggestions! Oh and I did grab the 160 tstat since it’s a GT-40.

[DLafont]

Seems to me like you've got a pretty good handle on things, all the principal components of the cooling system will be checked out by the time you have the TStat in there. Mine was behaving in similar mode at first put in this year, temp was rising steadily, although water temp was pretty cool. Turned out to be loose hoses and strainer. Runs awesome now.

[brettmcox]

Do you think that you might have flipped the housing. I took my boat the local Mastercraft Detailer "KCwatersport" and when they replaced mine, they flipped the house upside down. And, they did not know it because they used a hose to test it. caused my boat to over heat. that was not the ONLY issue.... they twisted my belts, replaced a battery because my starter relay was clicking then told me it was keypad...........

make sure you cannot see the screw on the OUTSIDE next to the wall. "If you can see the screw.... you are screwed"

[cal1319]

Hey everyone, so figured it all out. As for putting in the water pump correctly, I have it clearly marked with paint, so that was not the issue. The problem that I faced was something so easy and stupid it should have never happened in the first place. After we knew we had a blown impeller, we took the pump off, cleaned it up and put the new impeller in. I check to make sure the housing was clear of crap and such. Went back to the lake run much better still overheated. Next step took of the thermostat housing and it was looking really bad, rust and such, cleaned that all up, flushed those hoses and put in a new thermostat. Took the boat to the lake last night, starter her up still overheated. starting to get frustrated, thinking the RWP might be crapping out. Pulled the top hose impeller looked great, spun it all teeth there still looking new. Hooked garden hose up to the RWP output and flushed engine again, no blockage. So I really thought it was the RWP, so decedied to just pull it out if I was going to replace it in the next few days. Burnt the crap out of myself since the risers were still pretty hot, got the pump out and finally saw the issue. The intake of the pump was filled completely with pieces from the old impeller! So, took the pump apart to inspect everything cleaned it all out. Then flushed inlet hose to the RWP. Turns out when we fried the impeller the pieces got stuck in the inlet hose, and stupid me didn't think to flush that hose. Put everything back to gather, back to the lake and got to board a few times while the sunset! So dont be dumb like me and just flush everything if you burn up an impeller!

Cheers
Chris

[surroundsound64]

I was just about to post to make sure you got all of the old pieces out. Glad you figured it out!