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over heating problem new pump and tstats did not help

T

tkms002

Member
[FONT=&quot]I have a model year 2000 200 EFI Mercury outboard. This past August I was on Sturgeon bay and the water temp was in the low 70s. I was just cruising along a about 3000 RPM and the over heat warning horn came on. I looked at the temp gauge and sure enough it was at about 210 degrees. The motor was peeing well and the water pressure gauge was reading about 12 psi at that 3000 rpm.[/FONT]
[FONT=&quot]I replaced the thermostats and the water pump and had it out on a local lake with a water temp of 57 degrees this past week to do some testing. Ran a mile or 2 at 3000 RPM and the temp gauge again read 210 degrees but the warning horn did not go off. Probably just short of tripping due to the colder water.[/FONT]
[FONT=&quot]Running at ANY other RPM will cause the motor to cool off. I can run miles at 4000 RPM or at 2000 RPM and the engine stays cool(145 or so).[/FONT]
[FONT=&quot]Looking for any ideas.[/FONT]
 
ok how di I do a compression test? I have the proper gauge but dont know the proper preceedure or what I am looking for.
Thanks
 
1. Pull all plugs, hook the wires back to them and use them to ground the flow of current to the block.

2. Screw the gage into each cylinder, crank her over at least 3 seconds, take a reading. Dump the pressure in the gage each time.

3. Write down the readings on paper for each cylinder.

4. Report your findings here.

Jeff

“Let’s go Brandon!”
 
fastjeff said:
1. Pull all plugs, hook the wires back to them and use them to ground the flow of current to the block.

2. Screw the gage into each cylinder, crank her over at least 3 seconds, take a reading. Dump the pressure in the gage each time.

3. Write down the readings on paper for each cylinder.

4. Report your findings here.

Jeff

“Let’s go Brandon!”
Click to expand...

With the choke and throttle open.
 
I have not done a compression test yet but I replaced the poppet valve and the old one still looked pristine so I dont think that was the problem.
Hopefully I will get a day before ice up to run it on the lake.
 
[FONT=&quot]one thing I have not mentioned. I have a water pressure gauge and it shows a constant 12 psi at 3000 rpm but at 4000 rpm the pressure varies wildly from as little as 5 psi to about 10 psi but it runs at about 145 degrees at 4000 rpm.[/FONT]
 
[FONT=&quot]Well I got it on the water today. Water temp as 47 F. Ran the boat(after letting it warm up) at idle for a quarter mile and the temp topped out at about 150 ish then ran it up to 2000 RPM for 10 minutes or so and the temp topped out about 180 ish then ran it at 3000 rpm and them temp climbed to about 210 ish(no warning horn). Then I ran it at 4000 rpm and it cooled back down to 150 ish. I think of the water temp as near 80 it may have sounded the warning horn at 3000 rpm. So, this issue seems to persist after changing the poppet valve and all its parts.[/FONT]
[FONT=&quot]Any thoughts are welcome.[/FONT]
[FONT=&quot]Thanks[/FONT]
 
When you checked the popit, did you make sure the seat for the valve was knocked all the way in the exhaust adapter? If it is not the engine will over heat....

Check your cylinder heads when running, Make sure they are the same temp.
 
Docksidemarineservices said:
When you checked the popit, did you make sure the seat for the valve was knocked all the way in the exhaust adapter? If it is not the engine will over heat....

Check your cylinder heads when running, Make sure they are the same temp.
Click to expand...
Yes the seat is all the way in. Made sure of that.
Can I use a laser temp gauge to check the head temp?
Where is the best place to check the temp?
Thanks
 
fastjeff said:
1. Pull all plugs, hook the wires back to them and use them to ground the flow of current to the block.

2. Screw the gage into each cylinder, crank her over at least 3 seconds, take a reading. Dump the pressure in the gage each time.

3. Write down the readings on paper for each cylinder.

4. Report your findings here.


Ran a compression test. All cylinders between 113 and 118 psi.
Click to expand...
 
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