Merc 70hp

David R

Seaman
Joined
Aug 21, 2001
Messages
61
Hello all<br /><br />I'm buying a new used boat, a 16' (75" beam) 1987 Crestliner with side counsel. Its in good shape, no dings or patches in hull, new floor could use new seats.<br /><br />The marina that I'm getting it from hung a 70hp Merc, think its a 1988 (OA739861) as it is oil-injected. It has lots of power, but the idle seems rough to me. I haven't had many boats, so my experience with two strokes is limited. Evinrude in the 70's and 80's smooth idle, but had a tendency to idle down to nothing. In the 90's a force, Ok idle, but vibrated alot.<br /><br />This Merc will idle, but seemed like they had to help it a bit when cold. At idle even when warm it had this odd rolling kick.<br />Smooth, smooth, kick, smooth, kick, kick etc...<br /><br />The marina people kept telling us that it was completely normal, all two strokes do this.<br /><br />The other thing I noticed which is subtle, when accelerating, there was a point when the power flatten and engine sounded a little rough, then took off.<br /><br />I don't have to take the motor, but life would be easier. The motor does have to be dead reliable as the trip to the cabin is 14 miles of water.<br /><br />David<br /><br />Any opinions?
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Merc 70hp

Sounds like they gave you one of those miserable 2+2 engines that runs on only 2 at low rpms, David. Believe it or not, they intended it to do that. EPA stuff, very mickey mouse IMHO.<br /><br />Red sky at night. . .<br />JB :)
 

David R

Seaman
Joined
Aug 21, 2001
Messages
61
Re: Merc 70hp

I had wondered that a the time so I had asked. The answer was that no, this is a 3 cylinder. 2+2 is only available on 115's (and 125's I think he said?).<br /><br />On a different point, is this a 70hp at the fly-wheel or 70hp at the prop. I recall this discussion from other threads, but I'm not clear on the year the change was made.<br /><br />Further would boat ratings of the time reflect the change of rating systems?<br /><br />David
 
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