Merc question ?

LtMike

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Jul 21, 2007
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3
I don't know that much about o/b's as I probably should....but I have a problem, and b/f I go to the marina (big $$$) I thought I'd try here... I have a 17' Sea Nymph w/ a 60 hp Merc (circa 1985) and tried to take the bride out for a nice lil ride the other nite, now the boat was running just fine earlier...anyway out we went, we were vacationing just off lake ontario, on a small pond w/lake access, and shortly after planeing out (3/4 throttle) the motor seemed to loose power, bog down and smoked a little at the exhaust. I shut it down, checked the prop and found weeds- remove some and restarted- the motor seemed to idle fine, pumped water thru but had no power--- anyway the trolling motor got us back to the dock, my b-i-l looked at the lower unit, said it was weed bound, removed all the weeds and we tried it again--- start fine, idle ok, pump water thru, but again no power, like there's no top end.....any ideas what this affliction might be ?
The intakes seem to be clear, the impeller seems to be ok as the stream starts shortly after the motor starts- but no power ? ? Any help would be greatly appreciated- thanks, Mike
 

roscoe

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Oct 30, 2002
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21,764
Re: Merc question ?

It may have gotten hot enough to blow the head gasket, causing a low compression condition.

Pull the sparkplugs and inspect, looking for signs that water got in the cylinder.

Then do a compression check with a gauge, available at any auto supply store or decent hardware store.
 

LtMike

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Jul 21, 2007
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Re: Merc question ?

Would head gasket be a minor or major repair ? Im confidant I could change the head gasket on my riding tractor...would this be in the same ballpark ? I have very limited experience or knowlege of o/b's....any idea what the compression should be ?
 

Plainsman

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Apr 2, 2006
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Re: Merc question ?

Compression should be over 100 and with 10% of each cylinder.
 

Laddies

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Re: Merc question ?

In 1985 Mercury 60HP engines had no head gasket the end of the cyls. only had a water jacket cover, if it leaks the only thing that happens is the engine will leak alittle water around the spark plugs on the outside of the powerhead
 

LtMike

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Jul 21, 2007
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Re: Merc question ?

So, now I'm really confused......do I have a head gasket or not ? If there isno head gasket, what is causing the power loss ?
 

Laddies

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12,218
Re: Merc question ?

Mike start by checking compression--if it overheated it might have stuck a pistion ring. Next ck all cyls. for spark and if you have spark then the only thing left is the fuel system - the carbs could have a high speed jet plugged
 
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