1993 4.3LX overheating

[GalenC]

I just replaced the impeller and took a run it for awhile around the lake with no problems. As I was trailering it, the alarm went off and the engine was overheating. I shut it off and today put the ear muffs on and it is still running close to 200 degrees. Hoses are warm on both sides of the thermostat and cold water is coming out the prop. Where do I start to diagnois?

 

[dgolla]

Re: 1993 4.3LX overheating

I just suffered from similar circumstances. I changed my impeller and still had problems.... then I removed my thermostat housing and examined it. I found old pieces of impeller stuck in the intake and outake ports of thermostat housing. While housing was open I changed thermostat. ($30.00 part) My next step was going to be to examine the water pump, but the old pieces of water impeller were my problem.
Boat is now running great and used it for about 15 hours last weekend.

 

[bruceb58]

Re: 1993 4.3LX overheating

Ha this boat been run in salt water? if so, coluld be the risers are limiting the flow do to corrosion.

 

[GalenC]

Re: 1993 4.3LX overheating

I wasn't having problems before, I changed the impeller because I change the lower shift shaft seal and thought while I had the lower unit apart I would replace the original, which didn'tn look bad. So my question is, did I do something wrong installing the impeller, put it back together incorrecty, sucked something in there, or the thermostat??? What clues do I look for before I start tearing things apart???

 

[tystick]

Re: 1993 4.3LX overheating

If no problem before , the impeller you replaced is screwed up somehow. Did you replace with correct gaskets?

 

[Don S]

Re: 1993 4.3LX overheating

Make sure you have the vanes of the pump flexed the right direction when installed. You have a Gen II Drive and the impeller will not turn itself around like the older Alpha's would.
It could also be you picked up a plastic bag, or kelp, or ? ? ? over the intake while sitting at the dock and damaged the pump when it ran dry. When you shut the engine off, the bag would fall off

 

[GalenC]

Re: 1993 4.3LX overheating

I am pretty sure I installed everything correctly when I changed the impeller. As I held the housing in my hand looking at the impeller, the vanes bent to the right. The gaskets fit really only one way, so I think those are right. Can the key fall out? Is there a hose i can disconnect to see if the impeller is pumping? What clues are there if the thermostat is opening correctly. I only had the boat out twice last year and this was the first trip for this year.

 

[tommays]

Re: 1993 4.3LX overheating

http://www.boatfix.com/merc/Servmanl/14/14b3.pdf


have a look here on page 75 you have to turn the shaft clockwise when you install the pump


Tommays