Results 1 to 4 of 4

Thread: Steaming 350Q

  1. #1

    Default Steaming 350Q

    Hi Guys
    Have a little issue with the Stbd Thermocon 350Q in my 1975 35' Aft Cabin. Last fall I was coming back on the Main River when my buddy behind me called on the Radio to tell that my Stbd. engine seemed to be smoking from the exhaust. After inspection found that it was steam coming from the exhaust. Much more than on the Portengine.(Outside air temperature was about 40F.) Water flow seemed to be a little less, but as indicated water temperature was running normal I continued and planned to replace my impeller after docking.
    Next day I removed the impeller only to find it was still in good condition. I had replaced at the beginning of the season (5 months prior). I checked the raw water filter which was also OK. Now I was starting to runout of ideas. One of my buddies thought it might be a plugged riser or manifold.
    So...Now I have a brand new exhaust manifold with risers and still have a steaming exhaust. What I have noticed is that when I start up the engine everything is normal until the Thermostat opens. Now comes the extra steam.... Running out of Ideas again....Need help. Headgasket maybe????
    Lokking to hear your this,

  2. #2

    Default Re: Steaming 350Q

    Seems to be the norm for these CC's. I replaced both risers and manifolds, new thermostat, new impeller, new circulatory water pump on my 251 with 350 a Mercruiser . It still blows some steam. I stopped worrying about it.

  3. #3
    Join Date
    Jun 2008
    Island Heights, NJ,

    Default Re: Steaming 350Q

    Is the thermocon still factory stock, i.e., with original log style manifolds and pressure relief valves in the elbows? IFSO, check for plugged/stuck relief valve.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280
    1972 22ft Bristol
    Honda 7.5HP 4 stroke Long shaft

  4. #4

    Default Re: Steaming 350Q

    Hi Folks,
    Here's a short update on the "Steaming Issue". I think I've found the problem. After removing the oil cooler found a bunch of impeller blade pieces lay on the water input of the cooler. Hav'nt had the possilbity to check if this will reduce the Steaming problem but I will let you know when I'm back in the water. So Long.

Similar Threads

  1. 5.7 steaming
    By bcclew in forum Other Gas Inboard Mfgs IO and Sterndrive Questions
    Replies: 1
    Last Post: 06-16-2015, 06:43 PM
  2. steaming 318 inboard
    By nauti-gal in forum Other Gas Inboard Mfgs IO and Sterndrive Questions
    Replies: 0
    Last Post: 08-07-2014, 10:21 PM
  3. Crusader 350 steaming issue
    By foxsurf in forum Crusader Marine Engine Forum
    Replies: 12
    Last Post: 01-17-2012, 11:05 AM
  4. Excessive steaming
    By tjgimp in forum Mercruiser Sterndrive Archive
    Replies: 6
    Last Post: 06-06-2009, 11:25 AM
  5. Steaming exhaust
    By Ray Daoust in forum Archive 2002-2006
    Replies: 12
    Last Post: 03-06-2006, 02:59 PM

Posting Permissions

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