There, fixed now...

For pre 1975 outboards and race motors only.

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Rapier
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There, fixed now...

Post by Rapier »

I know people who have thought to do this but NEVER put it into practice.. :hmmm:
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Fasten bra straps and remove dentures...

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floater
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Re: There, fixed now...

Post by floater »

Does make you wonder why Mercury did'nt design a neat little cover to aid servicing particularly over such a key component.

On a similar note I was supprised that I needed to remove the entire powerhead form the mid section on my Evinrude 40 just to remove the head, although at least it is possible on the rude no hope on a Merc. :giggle:

Not as bad as Rover, to change the headlamp bulb on a 75 you have to take the bumper off :o

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Alacrity
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Re: There, fixed now...

Post by Alacrity »

It's hardly an arduous task getting to the bottom plug, you just use a spanner instead of a socket, and it is an outboard so hardly difficult to get at. See, simples! :woo:

You want to try working on some inboard applications to see difficult access. Many boat builders fit the engine(s) to hull then bond the deck/cockpit moulding on afterwards, making access nigh on impossible at times. :grrr:
Mercs are like women, no 2 are exactly alike. That's what testing is about. In general it is safer to test motors and props than women!

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floater
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Re: There, fixed now...

Post by floater »

Spanner, isn't that like mole grips but not as versatile.
Not easy to get the hammer in either :giggle:

About to make a start on my 79 Merc 80HP any weaknesses I should look out for? I have a new water pump to fit along with two full carb kits but this motor has been dormant on a stand for years so any advice would be helpful.

DH

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Alacrity
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Re: There, fixed now...

Post by Alacrity »

You have got the bases covered really there David, I take it as read you will do the l/unit oil as well & grease the swivel & tilt tube. I would also change the fuel pump diaphragm as they work hard. In a perfect world it would make sense to do the top & bottom crank seals as well (I am assuming compressions are good) but you may just want to run her up after you have done your service work & see how it goes. The ignition I believe you have on it (4 separate coils?) is the best Merc ever used on these (ADI - Alternator Driven Ignition) & it is very reliable, but you do here cases of stators, triggers, CDI box & coils failing. The coils, CDI unit & (I believe) trigger (depending on type) are common to the 50 & are always popping up on eBay or at jumbles for sensible money, the stator may well be the same as the later inline sixes as all it does is charge the battery & provide power for the ignition so no theoretical reason for it to vary, but I am not sure on this.

Probably not a bad idea to build up a 'stock' of some of these bits if you see them at a decent price, the coils & CD unit can be changed easily at a meet, if you take a flywheel puller the stator & trigger as well. I am painting a black picture here & don't mean to as it is a good solid engine & ign system you have there, but it is all around 30 years old now so its good to be prepared rather than have a spoilt meet.
Mercs are like women, no 2 are exactly alike. That's what testing is about. In general it is safer to test motors and props than women!

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floater
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Re: There, fixed now...

Post by floater »

Thanks for the tips, I will get a new diaphragm as you recomend and of course change the gear oil. The compressions are all good although the middle two are 10psi under the outer ones as far as I can remember. I checked it when I first got the motor about 5 years ago but it had been standing for a good while before that so it may be sticky rings. I squirted fogging oil in the bores and carbs at the time but then left it on the stand as I have had no use for it until now. I have another although slightly ealier basket case engine for spares including coils and magic box if needed.

I have a good selection of OMC spares that i have picked up at jumbles over the years largely through recognition but being new to the Mercury I have yet to get my jumble eye in.

The key thing that worries me is that I have never run this engine and plan to fit it to a newly refurbished and filled transom which I will have to drill for this motor I don't want to then find out the motor is a scrapper :grrr:

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Alacrity
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Re: There, fixed now...

Post by Alacrity »

Does it only bolt on or does it have thumb screws? If it has thumb screws then I would just clamp it on & try it - just don't corner hard or chuck the thing about! :shock: :shock: :(

Sorry don't know what you mean by OMC? I thought only Mercury made classic outboards?? :giggle: :hilarious:
Mercs are like women, no 2 are exactly alike. That's what testing is about. In general it is safer to test motors and props than women!

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Re: There, fixed now...

Post by se7en »

You really should consider changing the top and bottom crank oil seals, these will want changing if they are original, its not just for good running , if these seals are weak, you stand a good chance of wrecking the motor, as the bottom ones stop steam in the leg being sucked back into the bottom cylinder, you don't notice it at first, you notice it more when you come back to the engine a week or two later and its siezed !!! and the crank is scrap, I see this more than you think, do it, its cheap insurance in the long term.

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Re: There, fixed now...

Post by floater »

Thanks Se7en I will study my book of words. It is an easy job on a classic OMC but I know how Merc like to overcomplicate things.

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Alacrity
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Re: There, fixed now...

Post by Alacrity »

Easy job David, maybe a few more bits to than one of the funny jobbies you mentioned, but there really is nothing to it if you are half capable with a spanner (or mole grips in your case).

Keep your eye open for a proper Merc manual on eBay (I have one here you are welcome to borrow - once I have finished the 115 that is) & it is worth getting a combi flywheel puller/lifting eye (see HERE) as it makes life so much easier. I believe you have a US shipping address available to you.
Mercs are like women, no 2 are exactly alike. That's what testing is about. In general it is safer to test motors and props than women!

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