Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams included

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chewbacca

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Basically where my block meets with the outboards aluminium body, Basically where the block is bolted on the side where the spark plugs are.. There is water leaking through where the block makes contact with the shaft.<br /><br />Basically could this be a seal problem and it would just need me removing the block and replacing the seal, or could it be because of corrosion thanks to previous owners not flushing?<br /><br />Also if i pull the block, is it mandatory to remove the carbys and fuel pumps or can they stay on? <br /><br />Motor is a 1970 650 Thunderbolt 65hp, 4 cylinder.<br /><br />Thanks i will include a picture or where it is leaking as soon as I get back from school<br /><br /> :)
 
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andrewkafp

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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Chewey<br /><br />Upload the pic to here<br /> http://www.myfishingpictures.com <br /><br />May the Force be with you... Or Merc in this case :D :D
 
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chewbacca

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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

<br /><br />Theres the picture and a describtion of my motor.. The yellow is where the block ends and the box underneath it is where the block sits and the shaft starts<br /><br />Any ideas?<br /><br />Thanks
 
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OhNoMrBill1960

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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

I have never really looked at mine too closely and I have a 650 but an older one. But out of curiosity could it be the routing of the line for the pee-hole ?
 
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RICKRICK1

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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

You have a seal between the head and mid section that is leaking. It will require removing the head from the mid section. You can leave on the carbs, fuel pumps, distributor. I do recommend removing the starter as it adds the most weight. Best to use a hoist when lifting and when seating the new gasket. Is also easier to remove/install the head if you remove lower unit first. If you do not have one now is the time to get you a manual on your motor.
 
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chewbacca

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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

i know this is a stupid question<br /><br />But what is the head.. Is the head the whole thing on the middle aka the block and everything?<br /><br />So if i remove the starter and i just remove the bolts holding the block onto the mid section and the pee hole hose and other items holding it down.. the whole thing will just lift off?<br /><br />Will there be problems such as seized bolts and the such you think?<br /><br />Where would i get a new seal you think? Or would i have to make it myself out of graphite paper?<br /><br />Manual is the go on my next shopping trip but i need to find out which ones the best, would the original mercury workshop manual be the best?<br /><br />Thanks gents and ladies
 
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RICKRICK1

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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Chewy-- I have the Mercury Factory manual. I like the factory books but some of the others give as much and some times more info of a basic nature as the factory book is really written for people who they hire with a basic understanding. Go to your local libray and look at which manuals they have and then make your choice.<br /><br />The head/block is the part that holds the pistons and crank. For your motor you will need to remove the wrap cowl, front and rear support brachets top bracket, remove lower unit, cables at the motor, all wires from the internal harness that connect to the block, the pee tube from the bottom cowl and the bottom cowling (this is the under the midsection top part and covers the bolts which hold the bloc to the midsection. Best if your spray your bolts with an oil like Kroil the day before you start to loosen them. This is the simplefied version, you really need a manual before you start.
 
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chewbacca

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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

oh thats all ok then.. See i was afraid i would have to open up the block so i can actually see the pistons and that was what i was afraid of doing.<br /><br />Would there be anything i would have to take a note of apart from the obvious to line up later without problems. What is on the bottom of the block where the LU meets with the block? I would expect some sort of a cam? am i right<br /><br />Thanks :)
 
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sharkcat

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May 4, 2003
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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Hey chewy shouldnt you be using the Force...lol<br />To clarify RickRicks reply he is talking about the powerhead as opposed to the cylinder head.I hope you dont have too many problems getting the powerhead off as corrosion can be a real issue on these older engines.Remove the lower unit B4 you do anything to eliminate the possibility of the drive shaft being corrode into the crankshaft.Any mercury dealer should be able to get you a base gasket for your engine.But GET A MANUAL B4 you start...Good Luck :)
 
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RICKRICK1

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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Thanks Sharkcat-- I knew it was called something I just couldnt remember powerhead when I posted. Must have had a brain freeze.
 
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sharkcat

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Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Re: Mercury 650 Thunderbolt... Water Leaking.. tell tale is weak, Diagrams inclu

Must have been very cold to freeze a brain in texas...every things bigger back home in texas :D :D :D
 
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