Heating up at idle! FINALLY...IT'S FIXED!!!!

[Bucks45]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

Bubba....I'm not sure, but it is different than the one that came with my kit. Still didn't fix the problem though.

 

[ziggy]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

maybe i missed it. but i've not read where ya say whether ya got fwc or rwc. i do see you R&Red the t-stat

New thermostat (165 degree)

if you got rwc that 165* t-stat may be too high.
from my generic knowledge of boat engines, generally it's 140* for rwc and 160* for fwc.
whatever t-stat used starts to open at rated temp to full open at +20*..... so your 165* would be full open at 185*..

looks like ya got the book. do you have the right temp t-stat in it?

 

[Don S]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

You might try pulling the risers and checking the ports to see if they are open. Another place to look is the water hose between the transom shield and bellhousing. A kink in it could really slow the water down at idle, but at higher speeds and more pressure from the pump it would cool.
There are some output tests in the serive manual that you can use to check pump output. Look at pages 6A-4 & 5 of OEM manual #9.

 

[bigcathunter]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

You should check the springs on the check balls in the thermostat housing, if they are weak it will overheat at idle and go away at higher revs. Pull them out and strech them out. and that will hold them tight when at idle and send water through the motor instead of straight out the exhaust.

 

[Bucks45]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

You should check the springs on the check balls in the thermostat housing, if they are weak it will overheat at idle and go away at higher revs. Pull them out and strech them out. and that will hold them tight when at idle and send water through the motor instead of straight out the exhaust.

I noticed that those are fairly loose when I changed the t-stat. What are they called? I noticed there was a nut on one end and a screw on the other. How tight are they supposed to be?

 

[Fun Times]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

Took the boat out for the first time today. It ran pretty well, but was heating up at idle. It would start cooling off when I increased the rpm's. I didn't let it get past @ 175-180. The impeller and pump were new last spring, as well as the thermostat. I'm assuming it has to be the water pump on the engine. Do you guys agree? If so, where do I get one? Can a automobile pump be used? It's a 1987 Mercruiser 5.7 (260). Thanks guys!

I was looking something's over and you may be running the wrong temp thermostat also.

I know you you could run both temperature thermostats (140) or (160) But if you look over the Standard cooling DESIGNS 1, 11, and 111 you will notice they offer both temps, But to me they are running the 160 DEGREES)BODENSEE, What ever BODENSEE means I'm not sure???
Just thought I would bring this up just in case.

http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=816596

 

[Bucks45]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

I was looking something's over and you may be running the wrong temp thermostat also.

I know you you could run both temperature thermostats (140) or (160) But if you look over the Standard cooling DESIGNS 1, 11, and 111 you will notice they offer both temps, But to me they are running the 160 DEGREES)BODENSEE, What ever BODENSEE means I'm not sure???
Just thought I would bring this up just in case.

http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=816596

You guys are right. I checked the manual and it's supposed to be a 140. I'm going to change it. My concern is that there was a 140 in it. It checked ok in a pot of water on the stove. I only replaced it because I had it out. I'm not sure that's the problem. I pulled the hoses off to look at the check balls again. They're tensioned as tight as they'll go. They seem loose, but when I pull on them they pop right back into place.

 

[bigcathunter]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

Maybe take some sand paper to where the check balls seat, the springs should hold them fairly tight if not just strech them.

 

[z284u2try]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

Is 180 actually over heating? I run a 160 stat and my boat also runs @ 180. Maybe I should step it down to a 140 stat.

 

[PitchFork]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

I have a 140? TStat and at idle I run around 160? but if I idle for more than 5 or 10 minutes the temp starts to creep to 180? to 190? then Alarm so it may be time for a new impeller for me which I will be doing at the end of the month. I may check the check ball tension and sealing and the oil cooler for blockage. It runs deadon 140? while on plane or anything above 1000 RPM to WOT.

 

[Bucks45]

Re: Heating up at idle! FINALLY...IT'S FIXED!!!!

Finally......went out this afternoon and stretched the springs on the check balls, put the 140 thermostat back in it, and crossed my fingers! It heated up to about 160, at idle, and stayed there! Guys, I can't thank you enough for all the help. Next time I read a post from someone in my situation I may actually have a good suggestion!

Thanks Again,
Aaron

 

[liquidlew]

Re: Heating up at idle! FINALLY...IT'S FIXED!!!!

I'm late to this post, but I thought I would throw this out there too, since I had the exact same problem 2 years ago. After new impeller kit, t-stat, water circ pump, manifolds and risers, plugs, cap, rotor, wires, checking and rechecking for flow, it was all good but still creeping up hot at idle. Decided to break out the timing light and Bingo! (Someone didn't tighten the dist bolt down enough:redface It was off enough to make it run hot but still idle good. Reset it to the spec for my motor and problem solved!

 

[ziggy]

Re: Heating up at idle! FINALLY...IT'S FIXED!!!!

Decided to break out the timing light and Bingo! (Someone didn't tighten the dist bolt down enough:redface It was off enough to make it run hot but still idle good. Reset it to the spec for my motor and problem solved!

fwiw.... the oem service manuals is great. the one i use, #2. in the trouble shooting guide. under overheat conditions. under other. improper engine ign. timing is the second item listed as a possible cause for engine overheating. love my mercruiser s/m....

Bucks45, glad ya got your problem fixed. congrats..

 

[Fun Times]

Re: Heating up at idle! FINALLY...IT'S FIXED!!!!

Nice, Good job, Glad you got it fixed and that we could help you out with it.

 

[RepoMan207]

Re: Heating up at idle! FINALLY...IT'S FIXED!!!!

I'm late to this post, but I thought I would throw this out there too, since I had the exact same problem 2 years ago. After new impeller kit, t-stat, water circ pump, manifolds and risers, plugs, cap, rotor, wires, checking and rechecking for flow, it was all good but still creeping up hot at idle. Decided to break out the timing light and Bingo! (Someone didn't tighten the dist bolt down enough:redface It was off enough to make it run hot but still idle good. Reset it to the spec for my motor and problem solved!

That's awesome. Mine still overheats at idle unless I crank it up. I'll have to check that out as well. I too put in TStat, Brand new raw water pump, new hoses, risers, manifolds, checked and re checked flow about a dozen times, belts.....I'll get the timing checked out. Thanks for mentioning that.

 

[Lou C]

Re: Heating up at idle! FINALLY...IT'S FIXED!!!!

Good diagnostics....If you have a 160 stat the engine should run close to 160...at least in my experience that's what my 88 4.3 runs at with a good thermo and impeller...when the thermo gets sticky then it will take longer to warm up and only reach 160 when its on plane otherwise it won't get over 120...so I have to change the stat every couple of years and I put in a new impeller each season as a matter of course....but the old ones always look fine....

 

[crazy charlie]

Re: Heating up at idle! FINALLY...IT'S FIXED!!!!

what was the fix ?????

 

[Bucks45]

Re: Heating up at idle! FINALLY...IT'S FIXED!!!!

what was the fix ?????

The springs on the check balls, inside the thermostat housing, just need stretched out. Fixed the problem right away. I ordered a new set just to make me feel better about it happening again.

 

[achris]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

...What ever BODENSEE means I'm not sure???...

Bodensee is the German name for Lake Constance, a lake on the Swiss/German/Austrian borders... The emission regulation there are a lot tighter than elsewhere, so some parts are 'Bodensee' specific.

Chris.....

 

[Fun Times]

Re: Heating up at idle! UPDATE

Re: Heating up at idle! UPDATE

Bodensee is the German name for Lake Constance, a lake on the Swiss/German/Austrian borders... The emission regulation there are a lot tighter than elsewhere, so some parts are 'Bodensee' specific.

Chris.....

Thanks Chris for the good information on that, When I tried googling it, The only thing I really could tell was it must be something in German, But that was about all the information I could get out of it really.:redface: Thanks again.