2004 Johnson 115 question

guitar pickerguitar picker Posts: 110 Officer
2004 Johnson 115 2 stroke salt water edition. The hot alarm goes off when running over 3/4 throttle. Just had the 100 service done thinking new impeller and thermostat would fix this. Took it out the day after and it ran fine. Yesterday started doing the same thing. Motor runs fine below 3/4 throttle above that the alarm goes off and it sounds like it gets flooded and looses power. If at this point I put in neutral or reverse the alarm turns off but when I give it throttle it sputters. Shut the motor off and start right back up and it runs fine untill I run up RPMs to 3/4 and in a little while same thing . I have had the boat for 5 years and it has done this intermittingly since I purchased it. It might run fine for a few months then start doing it again. Boat runs WOT at 43 mph I usually run between 25 and 33 mph
This starts happening above that.
Any Ideas???


  • BillgranBillgran Posts: 338 Deckhand
    A good tech would temporarily hook up a water pressure gauge and run the motor looking for low or erratic pressures at high speed. It is also easy to install the wrong water pump kit as there are 2 types that look almost identical. The wrong one results in lower water pressure.

    Any transducers, thru-hull fittings, or speedo pickups within 14" of the engine centerline can affect the cooling system by disturbing the water flow going into the gearcase inlet screens.

    Is the flusher fitting installed that can direct the "pee stream" in any direction?

    It may be a good idea to use an infrared temp gun on the cylinder heads to see if they are really overheating and not a faulty temp sender or switch. I am assuming that the HOT light comes on when the motor starts to slow down automatically and the horn goes on for about 30 seconds

    I can't believe that you are fighting this for 5 years. What did your dealer do for the first 2 years of warranty to fix the problem?

    "There is never just one thing wrong with a boat"
    --- Travis McGee

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