Running Hot

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   Took my 89 SN out to the lake today for the first time (been restoring it since I bought it last November). I had put in a new thermostat (142 degree) and water impeller. Tested great idling at home with the plunger/“fake-a-lake” attachment and hose and seemed to run fine. Temp stayed around 160 degrees.  At the lake today, when I would accelerate, it would go to approx 200 degrees and sound the alarm. Then, I would decelerate back to idle and temp would go down to 175 or so. Checked strainer (clean and seal appears to be good) with no noticeable air leaks.  Checked exhaust tube for any obstruction and it’s clear. I’m perplexed as to what would cause this and next steps to check. Any thoughts?  Thanks I’m advance. 

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bfootr Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: March-04-2019 Location: Benson, NC Status: Offline Points: 138	Post Options Post Reply Quote bfootr Report Post Thanks(0) Quote Reply Topic: Running Hot Posted: April-30-2019 at 5:28pm
	Took my 89 SN out to the lake today for the first time (been restoring it since I bought it last November). I had put in a new thermostat (142 degree) and water impeller. Tested great idling at home with the plunger/“fake-a-lake” attachment and hose and seemed to run fine. Temp stayed around 160 degrees. At the lake today, when I would accelerate, it would go to approx 200 degrees and sound the alarm. Then, I would decelerate back to idle and temp would go down to 175 or so. Checked strainer (clean and seal appears to be good) with no noticeable air leaks. Checked exhaust tube for any obstruction and it’s clear. I’m perplexed as to what would cause this and next steps to check. Any thoughts? Thanks I’m advance.

75 Tique Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Grand Poobah Joined: August-12-2004 Location: Seven Lakes, NC Status: Offline Points: 6097	Post Options Post Reply Quote 75 Tique Report Post Thanks(1) Quote Reply Posted: April-30-2019 at 5:41pm
	Fake a lake is going to push water through engine, so not a cooling system test. Go back to the driveway. Disconnect intake hose, extend if necessary, put in 5 gallon bucket of water. Should draw bucket down pretty quickly. If not, tighten all connections, you already checked strainer, New impeller should be fine. Was old one OK when you took it out. If broken up, there could be pieces clogging system somewhere.
	_____________ “So, how was your weekend?” “Well, let me see…sun burn, stiff neck, screwed up back, assorted aches and pains….yup, my weekend was great, thanks for asking.”

bfootr Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: March-04-2019 Location: Benson, NC Status: Offline Points: 138	Post Options Post Reply Quote bfootr Report Post Thanks(0) Quote Reply Posted: April-30-2019 at 5:59pm
	Thanks for the response. Yes, old impeller was broken and missing most all of the vanes so indeed pieces could be clogging the system somewhere. Should I start disconnecting water lines to see what I find?

75 Tique Members Profile Send Private Message Find Members Posts Visit Members Homepage Add to Buddy List Grand Poobah Joined: August-12-2004 Location: Seven Lakes, NC Status: Offline Points: 6097	Post Options Post Reply Quote 75 Tique Report Post Thanks(0) Quote Reply Posted: April-30-2019 at 9:23pm
	start at the thermostat housing..
	_____________ “So, how was your weekend?” “Well, let me see…sun burn, stiff neck, screwed up back, assorted aches and pains….yup, my weekend was great, thanks for asking.”

KENO Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10645	Post Options Post Reply Quote KENO Report Post Thanks(1) Quote Reply Posted: April-30-2019 at 9:54pm
	then after that follow the hoses from the thermostat housing to the exhaust manifolds and unhook them from the manifolds. The exhaust manifold inlets are a favorite hiding spot for some of those chunks. You should look in the manifolds where the fittings screw in as it it pretty tight right there. Take the fittings off to get a better look. If the manifolds are restricted , the flow through the engine is restricted too since the flow exiting the engine leaves through the manifolds

samudj01 Members Profile Send Private Message Find Members Posts Add to Buddy List Gold Member Joined: March-10-2009 Location: NC Status: Offline Points: 933	Post Options Post Reply Quote samudj01 Report Post Thanks(1) Quote Reply Posted: May-01-2019 at 12:28am
	Make sure the belt is tight...got us once and luckily someone spotted it in our video we posted
	78 Ski Tique, 72 Skier w/302's, 93 SN w/351 & 17 GS22 w/zr409 Previous - 99 Sport Nautique w/GT40 and 87 Martinique w/351

bfootr Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: March-04-2019 Location: Benson, NC Status: Offline Points: 138	Post Options Post Reply Quote bfootr Report Post Thanks(0) Quote Reply Posted: May-03-2019 at 9:04am
	Thanks for the responses. Sure enough, broken parts of the old impeller were clogging the water pump inlet hose. Running great now!

8122pbrainard Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040	Post Options Post Reply Quote 8122pbrainard Report Post Thanks(1) Quote Reply Posted: May-03-2019 at 9:09am
	Bill, I'd like to add that running the engine dry will burn up a rubber impeller pump within minutes since they are water lubricated. I've even seen it at the launch when the owner decides to " we had better see if the engine starts before we put it in the water."
	54 Atom 77 Tique 64 X55 Dunphy Keep it original, Pete <

bfootr Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: March-04-2019 Location: Benson, NC Status: Offline Points: 138	Post Options Post Reply Quote bfootr Report Post Thanks(0) Quote Reply Posted: May-03-2019 at 1:36pm
	Great reminder! That’s what happened to me. Lesson learned!

rakerdeal Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: January-10-2018 Location: Lexington, NC Status: Offline Points: 92	Post Options Post Reply Quote rakerdeal Report Post Thanks(0) Quote Reply Posted: May-22-2019 at 9:02am
	This is a great thread. For whatever reason I burned up a new impeller this year, then found this discussion and........ .....found pieces of it in all the places listed above! New impeller and all is fine.
	CYS

MrMcD Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: January-28-2014 Location: Folsom, CA Status: Offline Points: 3590	Post Options Post Reply Quote MrMcD Report Post Thanks(0) Quote Reply Posted: May-22-2019 at 3:25pm
	Those loose chunks of a bad impeller can ruin a ski trip for sure. For this reason, and with 40 years of tounament boat ownership I have for many years now changed out the impeller every other year. It has kept my impeller intact for many years now. You can look up the Timmy T and add it to your inlet hose, it works very well for running your engine at home, better than a fake lake, I have one of those also.

aupatking Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: October-03-2013 Location: Alabama Status: Offline Points: 139	Post Options Post Reply Quote aupatking Report Post Thanks(0) Quote Reply Posted: June-10-2019 at 1:10am
	I’m fighting with the opposite problem on my GM Excalibur 330. It’s idling warm, over 200 (is my guess) and normal 175-ish at speed. That says to me, new impeller. Brand new impeller and I’m seeing the same thing. Shouldn’t I see a visual “swooshing” of water through the strainer? I feel like water is not being sucked in to the system. I have: flushed the system backwards from the raw water pump intake side back through the trans cooler. Checked for flow from the through-hull and valve. Checked the thermostat housing for remnants of any old thermostat Checked exhaust elbow for inner corrosion. Pulled hoses from thermostat to recirculating pump Pulled hoses from raw water to thermostat All with no positive effect
	02 SN 196 TSC2 ZO 01 SN 196 TSC1 98 SN 196 TSC1 97 SN 196 TSC1 93 SN 196 NWZ

8122pbrainard Members Profile Send Private Message Find Members Posts Add to Buddy List Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040	Post Options Post Reply Quote 8122pbrainard Report Post Thanks(0) Quote Reply Posted: June-10-2019 at 7:15am
	Patrick, Check the gasket on the sea strainer. Sounds like you may be sucking some air.
	54 Atom 77 Tique 64 X55 Dunphy Keep it original, Pete <

DVskier Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: September-04-2014 Location: Seneca SC Status: Offline Points: 449	Post Options Post Reply Quote DVskier Report Post Thanks(0) Quote Reply Posted: June-10-2019 at 10:58am
	I had a somewhat similar issue and found that by thoroughly cleaning the threads on the spin on water strainer it restored normal operation. The gasket was in good shape. I used an old toothbrush to get all the built up crud off.

Running Hot

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