Logo
Click for Crusader parts and manuals!
Results 1 to 8 of 8
  1. #1

    Default Kohler gen not working under load

    My generator is a Kohler Model 7.5A27; Serial number 490638 at 1800 RPM. The volts drop down to 900 or below when hot water heater , stove or AC is on, but not at the same time. It is 38 years old original to my 1978 carlcraft (Gibson) houseboat with twin 270 crusaders. Gen mechanic advised me some wiring maybe bad or loose, (if I am lucking) or the gen needed to be rebuilt but either way had to come out to work on it. The vessel is worth top end around 27K after 15 months of engine rework and upgrades to stringers, replace rotten wood, new cabling, etc. Does it make since to rebuild such an old gen or go with newer equipment in such an old boat? Newer meaning low CO and much more fuel efficient and less noisey. Bottom of her looks great as well as both engines were rebuilt with 600 hours on them now. Advise would be greatly appreciated.
    Last edited by jaybirdboat; 07-26-2016 at 12:53 AM.

  2. #2
    Join Date
    Sep 2006
    Location
    Baton rouge, La, USA
    Posts
    2,501

    Default Re: Kohler gen not working under load

    I had a 1973 identical kohler on a boat I purchased in 1973...the only problem I had with it was flaky auto charge for the battery..rewired it to where it charged max when ever it was running which is what I needed anyway..thats a heavy generator..if I remember correctly 250-300 pounds.. it also vibrated the whole boat when running..a long flexible pipe with a auto muffler took care of the noise.. I replaced it in1979 because of the weight and vibration...brought it home and used it for hurricane backup for decades...finally gave it to a painter in exchange for some work..

    I would replace it with a onan or a Honda and bring it home and troubleshoot it...there is a good market for the old cast iron 1800 rpm kohlers...if its not fixable then its a good parts motor and has good value..

    when trouble shooting it I would want to know what rpm its turning when its only putting out the low voltage...if the rpm is ok then its electrical..that generator will lug down when additional load is placed on it but should recover as soon as starting current becomes running current on the load..starting a air conditioner compressor for example...

  3. #3

    Default Re: Kohler gen not working under load

    Payson,
    i would like if all possible to fix the Kohler and save a ton of money as the new one are 10K or more for a 7.5 KW
    i am familiar with the onan built in gens but not the Hondas as I thought they were portable?

  4. #4
    Join Date
    Sep 2006
    Location
    Baton rouge, La, USA
    Posts
    2,501

    Default Re: Kohler gen not working under load

    I miss read ....I thought you were running a 4kw..it doe not matter on the basic question in rpm when running...

    the other two things are regulator and flashing the windings....the web is full of info on flashing...

    if you are getting 90 volts then I doubt if it needs flashing...my understanding is the regulator increases field current which increases ac output..a regulator will set you back 350 to 400 bucks..

  5. #5

    Default Re: Kohler gen not working under load

    Thanks for the info as I have a mechanic going to pull the gen for 300-500 depending on of the port exhaust manifold needs to come off. Then we will inspect the gen and decide course of action.

  6. #6
    Join Date
    Sep 2006
    Location
    Baton rouge, La, USA
    Posts
    2,501

    Default Re: Kohler gen not working under load

    let us know please

  7. #7
    Join Date
    Jun 2008
    Location
    Island Heights, NJ,
    Posts
    3,117

    Default Re: Kohler gen not working under load

    Is that 90 V at the outlet at the point of use, or 90 V at the generator? If the former, you have a wiring problem, if the latter, a generator issue.
    Capt Bob
    1969 23ft ChrisCraft Lancer
    Merc 5.7L 260HP/ Volvo 280

  8. #8

    Default Re: Kohler gen not working under load

    Quote Originally Posted by sandkicker View Post
    Is that 90 V at the outlet at the point of use, or 90 V at the generator? If the former, you have a wiring problem, if the latter, a generator issue.
    It is 90V at the meter just left of the helm. I am waiting on my gen mechanic to diagnosis and will get back to you

Similar Threads

  1. kOHLER 7.5
    By marko56 in forum Boat Electrical Systems
    Replies: 4
    Last Post: 06-25-2012, 12:13 PM
  2. KOHLER genset
    By kevin_z in forum Boat Electrical Systems
    Replies: 11
    Last Post: 01-21-2012, 09:09 AM
  3. Kohler 7.5r won't crank
    By n36511 in forum Miscellaneous marine engine topics
    Replies: 2
    Last Post: 06-16-2010, 08:43 AM
  4. Kohler gen problem
    By lugnutdan in forum Crusader Marine Engine Forum
    Replies: 4
    Last Post: 11-13-2009, 06:47 PM
  5. Kohler 73E
    By pfederlin in forum Miscellaneous marine engine topics
    Replies: 3
    Last Post: 04-29-2008, 10:36 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
  •