135 V6 Mercury showing hot on Gauge.

[Georgia Boy]

Hey Guys.
I have a 1987 135 V6 Mercury. so far I have changed the Pump, Poppit valve and Thermostats. I cranked the engine with the water ears and brought the engine up to a normal temp acording to the Gage. I ran the engine at 3000 RPMs( no load) The Gage moved close the hot indicator line. I did not get a warning horn ( I do not trust the horn only to protect my engine). The infared Thermometer read 187 degrees on port head and 170 on the starboard. I think this is too hot. The Pee stream is very good and water is comming out the exhaust looks normal. Any advice on to go from here?

 

[aussieflash]

Re: 135 V6 Mercury showing hot on Gauge.

Never ever run your outboard over 1500 rpm on hose with no load.Especially that motor.It's the best motor ever built.....I have same motor.I usually let mine idle for couple of minutes,then lift revs to about 1500.High revs with no load....not good.
Start your motor on hose let idle for 5 minutes (exactly),then let me know what temp gauge is saying.Has it overheated out on the water?

 

[Maxz695]

Re: 135 V6 Mercury showing hot on Gauge.

This one is all your aussie

 

[Georgia Boy]

Re: 135 V6 Mercury showing hot on Gauge.

Never ever run your outboard over 1500 rpm on hose with no load.Especially that motor.It's the best motor ever built.....I have same motor.I usually let mine idle for couple of minutes,then lift revs to about 1500.High revs with no load....not good.
Start your motor on hose let idle for 5 minutes (exactly),then let me know what temp gauge is saying.Has it overheated out on the water?

This started about 2 years ago. I had a major heart attack with surgery. and was in the hospital for 5 weeks. I had just picked up the boat from the tech that installed the water pump when the medical problem started The boat was in the water one time last year. I was aboard but not the operator. He did not mention the gage nor did I hear the warning horn. On the last day of a 4 day trip I did hear the horn when he was running about 3000 RPM. We cut the RPM back to 2000 and the horn stopped. The power did not cut back.and the engine did not appear to be hot I held my hand in the pee output with out a problem. We loaded the boat and came home. I just have gotten back on my feet enough to do some of the things I used to do. So I am working on the engine trying to troubleshoot a 2 year old problem. I thank you for any advice you can give me. I will follow you suggestion and post tommorow night.
Thanks again
Georgia Boy
Rex Mixon
BTW thanks for the RPM reminder. I always check the timming on my drag car at that number

 

[j_martin]

Re: 135 V6 Mercury showing hot on Gauge.

Don't know where you went for 4 days, or how much you were hauling back. (moose) If that engine is over propped, it'll tend to run pretty warm at mid speeds. I suspect you're worrying about nothing.

Back to Aussie

 

[aussieflash]

Re: 135 V6 Mercury showing hot on Gauge.

I did post earlier but my computer is playing up.I find mine will get a little warm when putting around 5 knots,though when I take off the gauge drops to cold in seconds.I'm due for impeller replacement soon.These motors like a lot of water so full blast when on hose.

 

[Georgia Boy]

Re: 135 V6 Mercury showing hot on Gauge.

Here is the Numbers
Port
Top 130
center 135
Bottom 129

Starboard
Top 146
Center 135
Bottom 143
This was after 5 Min. from cold start at idle speed.
I am sure when you put a load and increase PRM that the Gage will show hot. The gage showed on the center hash mark on this test. The poppit valve was replaced along with the thermostats. I have not observed gunk in the cooling passage at the poppit valve.
Thanks

 

[j_martin]

Re: 135 V6 Mercury showing hot on Gauge.

Here is the Numbers
Port
Top 130
center 135
Bottom 129

Starboard
Top 146
Center 135
Bottom 143
This was after 5 Min. from cold start at idle speed.
I am sure when you put a load and increase PRM that the Gage will show hot. The gage showed on the center hash mark on this test. The poppit valve was replaced along with the thermostats. I have not observed gunk in the cooling passage at the poppit valve.
Thanks

Looks good to me. What's your WOT RPM?

 

[aussieflash]

Re: 135 V6 Mercury showing hot on Gauge.

Damn thats another post gone....ill try again.
I agree with J on that one.It does sound fine.very close to mine.You say when horn went off you felt motor not hot.Im thinking faulty sensor/wiring on alarm.Tell me this,does your pee stream take 15 to 20 seconds to flow after starting on hose.

 

[j_martin]

Re: 135 V6 Mercury showing hot on Gauge.

Aussie, are you hitting that infamous blue "+Reply to Thread" button? We had a cry session about that one a couple of weeks ago.

Still waiting for numbers.

 

[Georgia Boy]

Re: 135 V6 Mercury showing hot on Gauge.

Yes
I will take the IFR Therm with me and and try it on the water and check Temps after WOT. I may be paranoid but I don't want any thing to happen to this rig. It is worth more to me than any body else. 1987 135 Merc on a 17' Glassstreme Bass boat. I can not rember RPM's at WOT. I have only had WOT a few times and just for a few seconds. On this trip we found fish just across the river about a half mile from camp. On the last day we made a 6 mile run to another location. This I became aware of the Problem.
Thanks Guys for the help.
Fishing on the ST Johns river out of Georgetown Fl

 

[aussieflash]

Re: 135 V6 Mercury showing hot on Gauge.

Aussie, are you hitting that infamous blue "+Reply to Thread" button? We had a cry session about that one a couple of weeks ago.

Still waiting for numbers.

I fiddled with deleting cookies on work iPad and it knocked out my auto sign in.I usually hit the "post quick reply" button....rarely the blue one.