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Mercury 6HP questions

Discussion in 'Boats and Motors' started by bkr43050, Sep 13, 2004.

  1. I am looking at a Mercury 6HP motor as a possible purchase. I plan to run it on my boat soon to decide if I want it. Initially what I have done is run it in a barrel. It runs pretty smoothly after the initial coughing (the motor sat unused for 2 years). I drained the lower unit and replaced it. The oil looked pretty dark but I found no particles in it and I did not notice any water. I noticed a couple of things I wanted to check into before putting it on the water. I know that a motor will smoke quite a bit more in a barrel than on the water and this one is smoking pretty good and particularly at higher throttle. The plugs seem to be staying pretty clean and they were on initial inspection. Are there any checks that I should do to the carburetor or anything else prior to putting it to the test? I used a 50:1 mixture. Is this correct? I apologize but I did not get the model number on the motor. I believe it is a 60's model. I will get the serial number today and post if that helps to know for sure.

    Also, the water flow from it is rather low. It barely trickles on idle and picks up some on faster speeds but not where it whould be. I noticed that there is a plug on the underside of the top section of the motor up by where the pee hole is located. This plug comes out with a regular screwdriver and is labeled "Fresh Water Flush". I figured that this is for cleaning the water pump area out? When I pulled the plug and looked up in it, it appeared to be completely clogged with what looked like hardened water. Should this port be clean? And if so what is the best way to do so?

    Thanks in advance!
  2. I am not sure of the year but here is a link to the motor.

    I found on that site that the 50:1 ratio should be correct.

    So does anybody have any idea on the fresh water flush plug?


  3. Skooky

    Skooky Fish Wizard

    I also have a 6hp mercury. a Merc60. I originally thought it was a '72 (it has a sticker on it hat says so) but thanks to the link you provided I found out it is a '68 (according to the serial number). I have the same problem you mentioned as far as the water outlet not being that great, sometimes it's barely a trickle sometimes it comes out ok. It may be the impeller (??).
    I checked the manual for it and the flush valve outlet is for flushing it out. The manual recomends that if it is clogged, to use a piece of soft wire to unclog it. From the sound of it though with the hard water residue built up it may take more drastic measures to clean it out. Would clr or something similar work or would that possibly mess up the insides?
    I'm pretty new to owning a boat and motor so I'm not sure if this is much help to you. I was wondering if this is a common problem on these models of merc (the water outlet). Maybe some of the more experienced boaters around here would know more.
    Anyways, thanks for posting the link. I definetly found it of use and plan on getting a water pump kit and to rebuild on mine.

  4. I think the first thing to do for either motor would be to replace the impeller. After sitting for that long, they can break down. If the water is still slow to come out, try unclogging the tell tale with a small wire while the motor is running (in water or hooked to hose). The flush plug, I believe, is for flushing out the system with fresh water.
  5. I can see up in the pee hole or I guess it is also called the tell tale (sounds better too;) :D ). It goes up a short way before making a quick turn and it all looks very clean in there. My guess is that there is no blockage in that area but I could be wrong. I will definitely get the impeller swapped out right away provided I buy the motor. What I am thinking about doing on the flush hole is using a small brush to clean it out, perhaps a dremel tool. But I don't know that this is even impeded the water flow at all or if it would only effect flushing the system through this port.

    I still plan to give it a run tomorrow night on my boat to try it out. I will be sure to take it somewhat easy on it to watch for overheating. If all goes well I will be buying the motor and then shopping for a Mercury manual. Then my next step will be to sell the nice Johnson 9.9 that I have.