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1992 Evinrude 150 HP heating problem

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fishin grandpa

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Having a problem with heating on a 1992 Evinrude Model E150GLENC and hoping someone can help me diagnose the problem. The water pump flow indicator has had a very weak
flow for some time so I pulled the lower unit and installed a new water pump. After re-installing the lower unit and test running with water hose and ear muffs the water indicator still
has a very weak flow. Before starting the engine I noticed what seems like an excessive amount of water coming from various parts of the lower unit. When I started the engine the flow indicator was no better than before changing the water pump and the high temp alarm sounded after just a minute or so. My initial thought was that I had not installed the water pump correctly so I pulled the lower unit again and checked everything again. All the new grommets for the water tube were good, the water tube is ok. I even measured the water tube length and checked the length to make sure it was inserted properly into the grommet in the exhaust housing. I felt confident that the water pump is ok so I inserted a plastic tube into the grommet in the exhaust housing and connected the water hose with minimal flow. Water is coming out around the drive shaft area and from the exhaust and still very small amount from the water pump indicator. I suspect the gasket between the exhaust housing and the engine has failed but I was hoping someone could confirm this before I tear it down and maybe offer some insight as to what would cause a gasket failure. Any help would be greatly appreciated!!!!
 
Are you getting an overheat alarm or just weak flow from the tattletale. If it's a weak flow from the tattle tale I would check that for blockages. Was the waterpump in one piece when when you replaced it. Water coming out of the holes in the lower unit is normal on muffs.
 
fishin grandpa said:
Having a problem with heating on a 1992 Evinrude Model E150GLENC and hoping someone can help me diagnose the problem. The water pump flow indicator has had a very weak
flow for some time so I pulled the lower unit and installed a new water pump. After re-installing the lower unit and test running with water hose and ear muffs the water indicator still
has a very weak flow. Before starting the engine I noticed what seems like an excessive amount of water coming from various parts of the lower unit. When I started the engine the flow indicator was no better than before changing the water pump and the high temp alarm sounded after just a minute or so. My initial thought was that I had not installed the water pump correctly so I pulled the lower unit again and checked everything again. All the new grommets for the water tube were good, the water tube is ok. I even measured the water tube length and checked the length to make sure it was inserted properly into the grommet in the exhaust housing. I felt confident that the water pump is ok so I inserted a plastic tube into the grommet in the exhaust housing and connected the water hose with minimal flow. Water is coming out around the drive shaft area and from the exhaust and still very small amount from the water pump indicator. I suspect the gasket between the exhaust housing and the engine has failed but I was hoping someone could confirm this before I tear it down and maybe offer some insight as to what would cause a gasket failure. Any help would be greatly appreciated!!!!
Click to expand...

Really not meaning to be offensive but based on your comment regarding the water coming out of the lower unit holes I think you may not have a ton of experience in this area so I'm going to throw out a couple obvious things.

For the engine to overheat in 1 minute it's as if you had very very little water flowing through it, like I'd be surprised if anything was coming out of the telltale, or the overheat alarm is somehow false.

#1 - Where are you located and is there any chance you have standing frozen water in the engine? It's below freezing where I'm at.. Although one would think it would just thaw out before it overheated, it actually can clog up your cooling system in places that do not get warm so fast and cause an overheat.

#2 - Absolutely agree w/ checking the telltale & plumbing up to it - real common for them to clog.

#3 - Have you ever run this engine on the flush with good pressure? Have you ever run another engine on the flush for a long time without an issue? It takes a certain amount of water pressure to keep an engine happy on the flush - some can barely be run on the flush without overheating. If your run is long, hoses small, water pressure weak, etc.. etc. It may just not work right. My experience is that engine should run just fine on the flush, but that's my flush/pressure/hoses and yours might just not work as well. It might be worth trying a barrel.

#4 - For like 30 bucks or something you can get a lazer temp gun at auto zone. These are real helpful trying to figure out overheat situations.

#5 - Are you absolutely sure the key in the water pump was correctly installed? It's possible to have this fall out of place during installation and potentially cause a similar symptom.

#6 - If you run the engine again, monitor the temp w/ a gun and you will be forwarned prior to an overheat, if you get an overheat when it doesn't seem like you should, real quickly figure out which sensor it is before shutting the engine off (usually unplugging them turns them off, I think you've only got 2).

Jon
 
Thanks for the reply.
I am getting an overheat alarm and weak flow from the tattletale. When I removed the old water pump it was in better shape than I expected. The impeller and cup showed little signs of wear and the impeller was still soft and flexible. I know you can expect some leakage when using the muffs and water hose but the leakage seems excessive. When I removed the lower unit the second time I installed the plastic hose with water hose connected into the water inlet in the exhaust housing to check the flow. I even removed the engine thermostats to check to see the water. I did get water through the thermostat openings and also out the tattletale but the leakage from the exhaust housing was considerable.
 
No offense taken. I'm open to any help I can get.

I'm located in central Texas and the temp has been in mid to upper 70s for the past week so ice in the engine is out. I have run this engine with muffs before but can't say that it has ever had what I would call strong flow out the tattletale. Even when running 40 mph on the lake it seems weak compared to others I've seen. It could be the overheating is because I'm starving it for water. I'll take your advise and get an inferred temp gun and try it again. I feel certain the water pump impeller and key are in properly. The force required to turn the driveshaft is considerably more with the pump in than when the pump is removed and when I try to turn the driveshaft counterclockwise it is extremely tight.
 
flyingscott said:
Find a laser temp gun and find out what the actual head temp is could be a faulty sensor.
Click to expand...

Someone else replied with the same suggestion. I've got one ordered and will test again when I get it. Could be that I wasn't putting enough water to the engine with the water hose. I'll find out soon. I'll let you know what I find.

Thanks again for your help.
 
flyingscott said:
Find a laser temp gun and find out what the actual head temp is could be a faulty sensor.
Click to expand...

Did a test run and checked temps with the laser temp gun. Temps were Ok but still had a weak flow even with more flow on the water hose. Ordered new temp switches and new thermostats. Replaced both and did another test. Water leakage from the lower unit was considerably less and tattletale flow was much better. Apparently the thermostats were leaking too much water that bypassed into the exhaust. Put it on the lake and everything was great.
 
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