Results 1 to 18 of 18
  1. #1

    Default Mercruiser 3.0 overheating, maybe....

    My engine may be overheating. At idle the gauge says it's running at 170-180 and under load is runs just a tick under 200, let's call it 195. I can't remember how hot it ran last year, but I've had the impeller changed professionally and was told that everything was good now. Well after running it all day at the lake I took a look to see what it should be running at and a google search that revealed that some people thing running at 200 is the beginning of boat apocalypse and others think that it's high normal.

    If I am running hot my next step is to change the thermostat, but the fact that it runs at a constant temp no matter how much load I put it under tells me that something is opening and closing, at least my mind thinks that should be the case. Also having run the engine for probably 4-5 hours like this, have I damaged anything else? Nothing seems to be broken but that just seems to be boatese for something is about to break.

    Finally what else could be the issue if the thermostat is working, or if replacing it doesn't fix the heat problem? I'd like to have a direction to go with this and not pay a professional $85 an hour on a diagnostic mission.

    As always any help is much appreciated.
    2003 Stingray 180ls

  2. #2
    Join Date
    Mar 2009
    Location
    Forest Hills
    Posts
    752

    Default

    Sometimes the sending unit can go crazy, I had one go on my 3.0, it kept showing my engine was running at 210 and when I would take the cover off the engine just did not seem overheated.

    Take the cover off the next time it shows hot, an overheating engine will be throwing off a lot of heat, you'll know it.

    I figured out my problem with a laser temp sensor and as it turned out my engine runs a bit cool, when I changed the sending unit all was good.

    BTW, had it been the impeller it would have overheated the first time you went out probably.


    Chuck

  3. #3

    Default

    It ran at the same temps the last time I was out, which was the first time since the impeller was changed. But it was a small lake and I honestly didn't think anything of it. But this weekend at Raystown I was staring at the gauge for hours and finally it dawned on me that I was pretty sure it used to run a lot cooler.

    When I got home from the lake today, I did a quick inspection of the engine to look for any obvious problems, mainly because there is some sort of oil coming out of my drain hole, which is new. The hose connecting the thermostat housing to the crankcase seems to have a blockage. I'll take it off this week and see if I can figure it out. It looks as if the guys that changed the impeller and gear lube overfilled the overflow tank and it leaked green oil all over. What color is gear lube? If it isn't green the what is?
    2003 Stingray 180ls

  4. #4
    Join Date
    Mar 2009
    Location
    Forest Hills
    Posts
    752

    Default

    Depends on the brand of outdrive oil they use.

    Hope it's really nothing at all I am sure Tony will post on this at some point. One thing you can try is to buy a laser temp sensor and point it at various points on the engine. I forgot what temp the engine should be at the various points though.


    Chuck



  5. #5
    Join Date
    Nov 2012
    Location
    RIYC
    Posts
    138

    Default

    The Mercruiser gear lube I use is green.
    Brondall
    Pero - Cruisers 2670 Rogue
    Prospect, KY

  6. #6
    Join Date
    Oct 2012
    Location
    Harrison City
    Posts
    676

    Default

    How did I miss this one??


    First... that engine can run at 200 all day long without an issue. When it's in a car... it would have had a 180~195 degree thermostat. So... on that side... I would say you are fine.

    BUT...

    IF your know it was running cooler before, I would make sure the thermostat isn't stuck. They do eventually go bad, and unfortunately... when then happens... they stick shut. (or don't open all the way)

    I may be out at Loyalhanna on Thursday. Let me know if you are free. I can take a look at it for you.
    Tony


    2002 Seadoo Islandia w/240EFI Sport jet
    2000 Polaris Genesis
    1996 Seadoo XP 800

  7. #7

    Default

    I'm sure it was running cooler before by about 10-15 degrees. i can meet you at loyalhanna on thursday if you end up going. text me and let me know.
    2003 Stingray 180ls



  8. #8
    Join Date
    Oct 2012
    Location
    Harrison City
    Posts
    676

    Default

    OK. I'll know for sure by tomorrow. (wed)

    I'll shoot you a txt when I know.


    I have another buddy/customer who has an issue with a Yamaha ski he just got. I think it may be overheating also.
    Tony


    2002 Seadoo Islandia w/240EFI Sport jet
    2000 Polaris Genesis
    1996 Seadoo XP 800



  9. #9
    Join Date
    Mar 2009
    Location
    Forest Hills
    Posts
    752

    Default

    Tony, don't you want the boat running on the hotter side? So as to not foul the plugs out?

    I had the reverse problem, I changed the impeller and now it runs a bit too cool.


    Chuck



  10. #10
    Join Date
    Oct 2012
    Location
    Harrison City
    Posts
    676

    Default

    Absolutely. Engines are more efficient when warm. AND, new engines are trending hotter. My new Ram runs around at 210 on both the coolant and oil. Even the trans runs at 185. And when I put a load on it... the oil will go up to 250 Deg F !!! But... that's still out of the red.


    But... if Dan has a free afternoon... and wants to hook up for a second opinion... why not go out on the water ? Besides... he has a question on the oil in the lower end, and a choke question from before. May as well look it all over at once.
    Tony


    2002 Seadoo Islandia w/240EFI Sport jet
    2000 Polaris Genesis
    1996 Seadoo XP 800

  11. #11
    Join Date
    Mar 2009
    Location
    Forest Hills
    Posts
    752

    Default

    I wonder if that green oil coming out is because of the O ring seal that sits between the two halves of the outdrive? It's a newbie mistake to leave that out but it makes you wonder?


    Chuck

  12. #12

    Default

    my outdrive has an overflow container attached to the engine. the green oil is coming from the overflow container. it looks like the seal between the container and the line that goes to the outdrive is leaking, possibly because it was too full.
    2003 Stingray 180ls

  13. #13
    Join Date
    Mar 2009
    Location
    Forest Hills
    Posts
    752

    Default

    Dan, now I remember and by reading it's probably a case where your outdrive oil was probably filled too high.

    In the end it's all probably nothing at all, good luck with it, Tony will know for sure what's up.


    Chuck

  14. #14
    Join Date
    Oct 2012
    Location
    Harrison City
    Posts
    676

    Default

    Dan... You should have gotten out there yesterday. It was a nice day to BS and tinker on stuff. Unfortunately... the other guy had a blown engine. (rear piston was melted)
    Tony


    2002 Seadoo Islandia w/240EFI Sport jet
    2000 Polaris Genesis
    1996 Seadoo XP 800

  15. #15

    Default

    i would have gone out there, but i have a huge make or break test next week and i thought i would have more time, but i didn't. the engine issues are on hold until i finish this horrible, possible career ending exam and my bank account replenishes itself. thanks for the offer though, i'm sure that i'll be hitting you up sometime in the next while. we should hit the river again this year though. last year was a nice day trip. maybe next month if you and your family are up for it.
    2003 Stingray 180ls

  16. #16
    Join Date
    Feb 2008
    Location
    Valencia, PA
    Posts
    391

    Default

    Ahh man...Where are your priorities...

    You could have studied on the peaceful, quiet water with no distractions under the sun light.
    Especially if it is a career ender, you may never (hope not) be able to afford to go on your boat again!!!!

    Good luck...
    2004 Supra Launch 22 SSV
    Indmar Assault 5.7L 325 HP
    "One More Hour"

  17. #17
    Join Date
    Oct 2012
    Location
    Harrison City
    Posts
    676

    Default

    Quote Originally Posted by Biohazdan View Post
    i would have gone out there, but i have a huge make or break test next week and i thought i would have more time, but i didn't. the engine issues are on hold until i finish this horrible, possible career ending exam and my bank account replenishes itself. thanks for the offer though, i'm sure that i'll be hitting you up sometime in the next while. we should hit the river again this year though. last year was a nice day trip. maybe next month if you and your family are up for it.

    Absolutely. My girls have been wanting to get out on the river again.

    I understand about the test... so no worries there. And, just an FYI... if I "Invite" you to hook up for a maintenance/tinkering party... don't worry about money. You should know by now... that's not who I am.

    I guess your kid should be getting big enough to try a wakeboard by now. (lol) My little girl finally decided to try to tube. (with a buddy holding her) She did good... but she did fall off at the end. (coming to a stop) She was fine, and she had fun. I think we got up to about 10 mph.


    Tony


    2002 Seadoo Islandia w/240EFI Sport jet
    2000 Polaris Genesis
    1996 Seadoo XP 800

  18. #18

    Default

    that's awesome, looks like she was having a lot of fun. we have only used the tube with my son when we are swimming, even then he likes being in the water more than being out of it. i appreciate the offer for help, but i didn't want to assume. if i can't nail it down i'll call you. i'll text you after august 1 (the last day of comprehensive exams) and figure out a weekend to hit the lake or river.
    2003 Stingray 180ls



Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •