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84 mcm 470 Getting warm

S

smchaplin

Regular Contributor
i know ive talked with you goo

i know ive talked with you good people before about this but its getting worse and need some direction on where to start. what the problem is is my engine runs great but on a long run it would heat up to about 170 and the quickly return to 150/160 when i pulled back on her. Now unless im just cruising 30/35 3000rpm she jumps up to 175 and im starting to get concerned. i took the heat exchanger off and removed both caps and the tubes look clear and open. i had a guy tell me yesterday that the water pump may be getting week but he is about 28 and his knowlage is slim. what do the pro's think
 
So when was the impeller last

So when was the impeller last changed ?

How often do you use your boat ?

Hows the anti-freeze/water mix in the engine?

Hows the thermostat and housing ?
 
"If the temp. does not climb d

"If the temp. does not climb during extended idling then I would run some heavy duty radiator cleaner in it, flush it out, run a cleaning brush thru the heat exchanger tubes and install a fresh 50:50 mix of quality antifreeze and see what happens.

Also consider switching to a synthetic engine oil. Merc. now offers a synthetic 25W40."
 
The impeller was changed just

The impeller was changed just before i got it. witch this fall will be a year. when i pull the rad cap the anifrezze looks to be pure. and i know thats not very affective. i only use the boat 2 days a month. but now that my sone has graduated and left for the army so its been an expensive 2 months so i plan on using it every weekend. now as far as the ther and housing i havent torn into it yet kinda wanted to get some advice. now the synthetic oil do you think that will disapate a good amount of heat .it will idle at 160 all day
 
""...synthetic oil do you

""...synthetic oil do you think that will disapate a good amount of heat .it will idle at 160 all day."

Synthetic oil will not break down, thin out and "coke", not cook, like conventional oils. Coking produces carbon particles when the oil gets too hot causing premature engine wear. Synth. oil is supposed to cause the engine to run cooler; I believe it does. I use it in 3 SUVs, my Nissan Titan truck and my 4.3L boat engine uses 15W50.

If you are using a quality 30wt or 40wt engine oil you should be in good shape. Since "it will idle at 160 all day" I believe your problem is inside the heat exchanger. I would take it to a radiator shop and have it professionally cleaned. Some owners w/the same engine have replaced the heat exchanger to a larger capacity due to the problem you are experiencing."
 
i will do just that GUY it has

i will do just that GUY it has the 4inch on it already. do they make a larger one then that? also would it hurt for me to pull the thermostat just to get me thru the 4th? if it will then i'll watch fireworks from the bank

thanks steve
 
enough said i'll leave it

enough said i'll leave it be and stop worrying. but i do need to get the antifreeze to a 50/50 mix

thanks a bunch guys steve
 
would you believe if i told yo

would you believe if i told you that it was 3 loose wires that was giving me the mis reading on my temp gauge? well it was . i had the dash out to clean all connections and repair/replace if any the connections well the last time out it appeared to get 5deg hotter and at some point i turned it off and when i refired it the temp gauge flickerd like they do when you ground them. so with that on my mind i decieded to go over my work and unpluged the master plug and removed the dash and found 3 loose wires on the temp gauge my fault i tightened them and then checked all the rest and put her back together and took her for a spin hard one at that and she stayed right at 160 so i thought you guys could use that info for your trouble shooting library
 
"<[img]"http://www.marineengin

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ROFLMAO"
 
Steve:

I'm not laughing

Steve:

I'm not laughing at you. It is the simplicity of the answer to the problem. I was sending you to the moon and back and all it was is 3 loose wires. Who would think the loose wires could create the symptoms they did. Sure did fool me.
 
I'm glad you did; it just

I'm glad you did; it just proves that one must look for the least obvious now and then. Happy boating.
 
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