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  1. #1
    Member
    Join Date
    Sep 2005
    Posts
    150

    90 yamaha pro v 150 overheating again

    I bought this motor new :: Has never been in salt water or left in the lake..
    In 2003 the buzzer would start to go off when runing over 3500 RPMS .. I put in new water pump + all new parts.
    Checked poppet valve --thermostats :: Did not fix .. just did not run it over 3500 RPM's. It started to get worse in 2006...took it to the shop. They did redo everything again for a good price. They said it was fixed...still it would over heat with the buzzer. They then removed heads, water jacket covers, and cleaned out all of the water passages...pricey job! This did fix it. I asked the mechanic if he had ever seen this problem before on a '90 Yamaha...he said a few had been that way.
    My problem is...it has started doing it again. Has anyone else had this problem? It is a pricey job to have it done and in a few years have it come back on you. Does anyone have any suggestions as to what could be causing this? I do not run wide open very often...surely that isn't my problem.
    I can do water pumps, and poppet valves but pulling heads, and water jackets is out of my paygrade. Thanks!

  2.  
  3. Member
    Join Date
    Jan 2010
    Location
    Port Neches,Tx
    Posts
    5,765
    #2
    It is likely the heads again. If you can pull a lower unit and change a water pump, you can pull heads and clean the water jackets. The only thing you will need is a torque wrench to insure you torque the water jackets and heads correctly, and the torque sequence, which is likely embossed on the heads.

  4. Member
    Join Date
    May 2012
    Location
    New Iberia, Louisiana
    Posts
    338
    #3
    Yamaha had very poor quality gasket's for a couple of years, including your's. All because of abestous. If components on powerhead were replaced with OEM replacment parts then they should be good. However if after market gasket's were used then all bet's are off. I suspect that the powerhead and mid section gasket's have rotted away allowing exhaust into the cooling stream. There is a simple test, remove top cowl, remove thermostat covers and thermo's back unit down at landing (fresh water only) start unit. Bring unit up to 3000 RPM in gear or watever is SAFE. There has to be a tremendous amount of water coming out. And continious. If it starts to fall off or you see exhaust gas or steam the replace mid section gasket's. Thank's Martin

  5. Member
    Join Date
    Sep 2005
    Posts
    150
    #4
    Thanks Charlie 206 and Mcyama!!!! Does anyone know where you might get some more information from a site that would have diagrams or pictures? I do better with pictures! I don't really know what I am looking at!
    Since it is spring fishing season, and the best time to bass fish...if I keep running low rpm's and don't have the buzzer going off...will it be okay to run it until later in the summer? I need all the advice I can get on this project. Even if I get someone to work on it, the shops are all backed up due to spring boating season. Thanks!

  6. Member
    Join Date
    Sep 2005
    Posts
    150
    #5
    ttt