Latest News: Forums Technical Mercury Outboard

  • This topic is empty.
Viewing 15 posts - 1 through 15 (of 18 total)
  • AUTHOR
    POSTS
  • #4250
    admin
    Member

    I have been given a 2.5hp 2-stroke Mercury, it has been used in the sea and I suspect that it was not well flushed with fresh water because although the engine looks mint under the cover the leg has a few areas where the paint has bubbled off through corrosion of the aluminium and I cannot get it to pivot on the bracket at all, it appears to be locked solid with corrosion (yes I have released the clamp screw).

    I don’t even know if this is water-cooled or air-cooled (I’m an outboard virgin). It has the serial number 09746854 and was made in Belgium, I think in 1991. I have not tried to start it because I assume it needs to stand in a barrel of water.

    Does anyone know what I’ve got and more importantly where I can get it looked at by a professional somewhere in the South East (I live in West Sussex) I’ve been Googling and although I can find plenty of people who want to sell me a repair manual, I have not yet found anyone to give me an opinion on its condition.

    Any thoughts much appreciated.

    #9778
    tempest51
    Member
    #9779
    krgough
    Participant

    Hi,

    My guess is that the service will be v. expensive and probably not cost effective on a 2nd hand engine. I’d be tempted to run it up in a bucket of water to see if it runs ok and to check for some exhaust/cooling water spraying out the back somewhere. My Suzuki has 2 little holes on the shaft facing backwards and the spray comes out of them. I run mine in an old bin. It’s possible to remove the prop first (take out the split pin and look for the shear pin behind the prop – you don’t want to loose that) – taking the prop off stops all the water shooting out of the bucket. But I usually don’t bother. Don’t over rev it – without the prop there is not much load and it is easy to get the engine screaming with only a little throttle. If no cooling spray then kill the engine before it heats up – if you let it get too hot it will seize up but you should be able to run it for a minute or two.

    If no spray then either
    – broken/damaged impeller – fairly easy to replace
    – Blocked cooling channels in the head/block – Head needs to come off to clear them. Mine has two sets of channels (one set you get to by removing the head (where the spark plug goes in) and one set (the exhaust or leg gasket – I don’t know the correct name) you get to by removing the shaft – Probably not for the faint hearted but it’s certainly very easy to do on my Suzuki. You’ll need new gaskets and make sure you chase and clear the channels all the way from one end to the other – it’s easy to miss bits – it’s incredible how they can get fully blocked and become almost invisible.

    regards

    Keith

    #9783
    admin
    Member

    Thanks for the reply Keith. Where is the impellor on your Suzuki? Where is the water intake? I only have a tiny hole down near the prop, maybe 4mm dia, I can’t see where water is drawn in for cooling.

    I guess all will be answered when I try to start it this weekend, meanwhile thanks also Tempest, there are a couple of dealers who might service it within 20 miles or so of where I live.

    Mike

    #9785
    krgough
    Participant

    Hi Mike

    From memory – the impeller is in the leg directly behind the propeller. I think on mine you remove the prop and then there are two nuts holding a plate where the propeller shaft exits. The impeller is behind that plate I think. I think there are slits in the housing behind the prop that are the water intake point??

    I’ll try to remember to take some photos tonight.

    BTW – I’ve never had to replace the impeller. I think mine still has the 25yr old original. But – My engine does not get used much (1-2 hrs a year). It does however get blocked cooling channels and every few years I need to clean them out. When I spoke to the Suzuki rep he said – run it in fresh every time you use it BUT it will probably still block up – He said the only cure is to use it regularly – then they tend not to dry out and block up. Mine blocks with a mixture of dry salt, mud and oil.

    regards

    Keith

    #9786
    krgough
    Participant

    Hi Mike

    Impeller – On the suzuki

    Found a handy exploded diagram on the web. My blue scribble shows where the prop sits. As I said you whip off the prop. undo the two nuts on the impeller plate and that’s it. I’ve also marked the water inlet holes and the impeller.

    [attachment=0:2uq96rhv]Impeller.PNG[/attachment:2uq96rhv]

    I have the other exploded diagrams showing where the gaskets are for the cooling channels – If you want them then let me know. Not sure how relevant it is given they are different engines.

    regards

    Keith

    #9787
    admin
    Member

    Thanks Keith, I will have a go at it this weekend. First quote was for £75 for a service including gearbox oil change. I don’t think there is a gearbox….

    #9788
    tempest51
    Member

    Mike,

    I’d really think it worthwile to phone and get advice direct from Mercury, they will advise on the best course of action. The quote you have for £75 is very good, and I would advise getting a trained person to look at the engine before you attempt to start it, otherwise there may well be tears. Mercury would most importantly advise on availability of spares, as you will need them in time. With info you will be able to decide yourself if it’s worth chucking money at the outboard. The last thing you need is to not be able to start the engine when you most need it, say 50 metres from the drop at Niagara!

    #9789
    krgough
    Participant

    Hi Mike

    You have some gears at the bottom of the shaft. There is a vertical rotating shaft going down the leg of the engine with a gear on the end of it, this meshes with a gear at 90 degrees to it to turn the vertical rotating shaft into a horizontal rotating shaft. There is a big screw on the bulge behind the prop on my engine to drain the oil that surrounds those gears. You unscrew it – drain the oil, invert the engine and refill. You need to use the right sort of gearbox oil. Check the manual or online.

    Check what you get for £75 -I suspect they change the spark plug, and the gear oil and grease moving parts. Probably not much more than that.

    Changing the plug, gearbox oil and checking the impeller is easy stuff. Taking the head off is (I admit) a bit advanced so you have to make your own choice there and definitely don;t do it unless you are absolutely sure you need to. My problem is that mine seems has needed this a couple of times so I need to do it myself or it would be too expense. Check the manual or online for the right sort of spark plug – mine needs one that is designed to run either hotter or colder than normal engines – I can never remember which way round it is.

    [attachment=1:21ezhbvk]Gears.PNG[/attachment:21ezhbvk]
    [attachment=0:21ezhbvk]drain plug.PNG[/attachment:21ezhbvk]

    regards

    Keith

    #9793
    admin
    Member

    I started the engine tonight in a bucket of water.

    One second later the water was no longer in the bucket but it was in all the drawers of tools in my bench, all over me, running out of the garage…. 🙄

    So it works (at least for a few seconds, one could wish for a neutral gear) and I think it is worth getting it serviced and into use.

    Thanks for the advice and recommendations.

    Mike

    #9795
    Swiebertje
    Participant

    ROTFLOL, You should take the propeller of first.
    😆 😆 😆

    #9800
    admin
    Member

    Yeah that worked better….

    #9802
    krgough
    Participant

    Hi Mike

    Did you see cooling water spraying out the back of the engine?

    regards

    Keith

    #9806
    admin
    Member

    Hi Keith, yes a short piece of small bore hose exits lower right side and a stream of water did emerge, you can just see it in the photograph. I only ran it for a few seconds, mindful of the advice to get it looked at by a service bloke in case there was no oil in the gearbox or the impeller was trashed, the engine has apparently not been run for years. The intake hole is tiny, only maybe 3mm and easily missed on first inspection, which was why I wondered whether it was air cooled at first, now I know. Thanks for all the help and advice.

    And I am glad I gave you all a few laughs about my flood, I didn’t have to share that…

    #9807
    krgough
    Participant

    Hey Mike

    I’m not laughing – I’ve done exactly the same in the past and much worse.

    If the cooling water is coming out then the impeller is fine. Change the plug and the oil and off you go.

    regards

    Keith

Viewing 15 posts - 1 through 15 (of 18 total)
  • You must be logged in to reply to this topic.