over heat?

[jigmister1]

87 black max 175 HP.

the temp guage runs up just a bit over 3/4 of its span.
It dose this when ever the boat is running up against current in the river.
No matter how cold the water is.

is this normal? I have installed a new impeller. twice now with the same results.
how can I be sure the engine is not over heating?

thanks in advance

 

[gss036]

Re: over heat?

How about checking your thermostats? They should be opening at 143 degrees. Use a pan on the stove with a cooking thermostat and see where they open & close. If they are ok, check the poppit valve and if you are still worried install a water pressure guage, pretty simply to do.
Having said all that, what does the temp do at idle or slow speeds? Have you tried running it with the cover off the engine and feel the heads? Lots of small things to troubleshoot, maybe there isn't really anything to worry about.

 

[jigmister1]

Re: over heat?

installed new poppet and t stats. still the same.
at idle she heats up to about 3/4. if I run at a moderate speed she cools down to about 1/2 and stays that way. at full speed against current it gets to about 3/4. At no time dose it get hotter than at an idle.


It is probably fine, but I dont want to find out the hard way.

water pressure guage is probably my next move!

where do I find one and how dose it install???

 

[Chris1956]

Re: over heat?

Water pressure gauges are available from all the major brands. (teleflex, faria etc) They are mechanical and you will need to install the gauge in the dashboard, and route the pressure tube to the motor, and tee it into the recirculation hose from the poppit to the top of the block. mercs do not show much water pressure, maybe 5 LBS at idle, 15 LBS at WOT.

 

[Faztbullet]

Re: over heat?

When you replaced the impellers did you replace gaskets also? I have also seen this problem as debris or gasket failing on divider plate. Water is fed to heads thru the divider plate and any restriction will show up as a warmer running head. It a easy but dirty job to replace gaskets and with it being a 87 and river use I would change and check them.

 

[ronnieboy]

Re: over heat?

i beg to differ, my 150 v6 merc, will go to 23 pounds of pressure running all out, 5800 rpm, and tilted max, ranger will be goin 63mph, loaded or not, gotta 4 blade turbo 2+2 prop. love it, ron

 

[gss036]

Re: over heat?

Some motors will give more pressure, but my OEM Merc manual said 2PSI @ idle and 12 PSI at WOT and that is waht my 1989 Merc 200 hp did. I think as long as you have good water flow you are ok. Check the water temp on the peehole and see how hot it is.. The guage/sender could be off as they work on resistance.