Please note this thread has been inactive for 90 days. For the best results, please start a new thread.
Results 1 to 5 of 5
  1. #1
    Join Date
    May 2008

    Default high oil pressure?


    I have been lurking the forums for a while now, taking in as much knowledge as possible. These forums are awesome and I have already learned quite a bit. Thank you all.

    Now for my problem, I have a 1998 Larson with a 5.7L Mercruiser 350 carbuerated engine. It has the alpha 1 outdrive. This boat might have 50 hours on it as my Dad didnt use it much. Anyway, it has sat for 2 years and recently my fiance and I want to get it out and use it. Well after going through it grease, oil, impeller, drive oil, bellows etc., I started it on muffs and after a few tries it started ok and ran for about an hour in the driveway. Checked the oil, looked good, no problems. Well I took it to the lake yesterday for the first time to bring up the RPMs and make sure everything is ok. After running it for about a half hour, I stopped, took a look at the engine and the dipstick and everything looked alright except my oil pressure gauge reads very close to 80psi and there is a small amount of water in the bilge. I did notice that while the engine was running a small drip of water every two or three seconds coming from the bottom of the front of the motor underneath the big pulley(flywheel?) at the bottom of the engine. I put my hand under there and couldnt feel and moisture or where it was coming from. I also felt under the water pump to see if it was coming from there and dripping down, but it was dry. Any ideas? I hate this feeling, my stomach is all up in knots because im assuming the worst has happened.

    Sorry about the wording, my engine vocabulary isnt up to par.

    Thanks in advance,


    Any idea

  2. #2
    Captain erikgreen's Avatar
    Join Date
    Jan 2007
    Minneapolis, MN

    Default Re: high oil pressure?

    Could be it's just running down from the water pump, or from one of the hoses there.

    Check the hoses for rot by squeezing them.. there should be no dry cracking of the rubber. Some of them have springs in them to prevent kinking, so be aware of that. I doubt the hoses would have gone bad in just a couple years, but you never know.

    Check the hose clamps on the water pump and thermostat, it's possible if the boat was drained for winter storage that they could still be loose.

    If your oil isn't milky and your engine runs ok you probably just have a loose connection somewhere, but the only way to tell is to find where it's leaking from.

    Sea Ray SRV-210 - Winter refit
    75-85 foot displacement hull trawler - gleam in my eye

  3. #3
    Rear Admiral 180shabah's Avatar
    Join Date
    Mar 2005
    South Boston. Va

    Default Re: high oil pressure?

    80 PSI at what RPM? At what temp? With what oil?

    Check the oil for water contamination - if it is clean then stop fearing the worst. Hook up a mechanical oil pressure gauge and get a true reading. The dash gauges are not know for thier accuracy.

  4. #4
    Join Date
    May 2008

    Default Re: high oil pressure?

    Thanks for the responses guys. It doesnt matter what RPM I am running, the gauge stays close to 80 psi. The temperature is always perfect stays right at 160. I used the quicksilver oil recommended for the engine. I cant remember what weight it was.


    Last edited by TD2247; May 21st, 2008 at 01:36 PM. Reason: temperature

  5. #5
    Fleet Admiral Gary H NC's Avatar
    Join Date
    Dec 2005
    East of Charlotte NC.(Indian Trail)

    Default Re: high oil pressure?

    If the oil continues to look ok and not over full on the stick take it to the lake and run it a while.
    Very possible the oil sender is the problem.
    Go over every hose clamp and snug them up..
    Oil pressure sender or gauge is an easy fix..

    1981 ChrisCraft 210 Scorpion K,175 Johnson SeaHorse

Similar Threads

  1. Oil Pressure To High?
    By chaddeems in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 2
    Last Post: July 14th, 2005, 10:38 AM
  2. Is My oil pressure too high?
    By MIKESCHWARTZ in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 9
    Last Post: June 7th, 2005, 06:40 AM
  3. High oil pressure
    By BubbaBaxter in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 3
    Last Post: May 28th, 2004, 10:15 AM
  4. High oil pressure
    By orion208 in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 3
    Last Post: July 12th, 2003, 05:01 AM
  5. high oil pressure
    By orion208 in forum Mercruiser I/O & Inboard Engines & Outdrives
    Replies: 4
    Last Post: July 3rd, 2003, 01:16 PM
  1. iboats Forum Directory - Over 100,000 forum posts organized by topic