old 76 merc

[procraftmark]

I was looking at replacing my 90hp rude with this ol 1976 65hp merc the rude is going to need more repairs than i can afford. Was that yr of merc a decent motor? I want to put it on my procraft 1650 glass f/s . I doubt if it would get on plane but it should push it around 25mph or so shouldn't it? The rude has tilt/trim and with this setup the top mounting holes are slightly offset "wider" than the bottom ones! On the merc it looks like the holes are all in-line, I was trying to avoid putting any new holes in the transom. Also there are a few cescent shaped notches out of the skeg, how will this affect performance?<br /><br /><br />thnx<br />mark

 

[emckelvy]

Re: old 76 merc

Don't think you're going to be happy with the performance of a 43 CI 3-cyl 65 over your 90HP V4.<br /><br />You definitely would need to drill new holes and plug the old ones as Merc's of that vintage didn't have the standard mounting bolt pattern yet.<br /><br />If you do get the Merc, make sure you get the control box with electrical harness, they are not as easy to find as the standard Merc harness.<br /><br />And definitely do not overprop this motor, it must be allowed to rev up to its correct rpm range at full throttle. It develops far less torque than your 90HP and won't tolerate lugging.<br /><br />You probably won't notice much diff in performance from the busted skeg, maybe a slight loss in directional stability, but it likely won't be able to develop the speed necessary for those problems to become noticeable.<br /><br />Check the compression of the 65 before you get it, this was a very highly-stressed motor and if it has any cylinder-sealing problems you won't get much performance out of it. Also look for signs of overheating, usually when these do overheat it will crack the block around #1 cylinder.<br /><br />HTH.........ed

 

[procraftmark]

Re: old 76 merc

anybody else think this is crazy? Would it even get on plane?. You are lookin at a guy desparate to just get back on the water<br /><br /><br />mark

 

[procraftmark]

Re: old 76 merc

bump

 

[andrewkafp]

Re: old 76 merc

Depends on how much you are paying for the Merc.<br />Pre-1978 (I think) did not have S/S driveshaft. You need to make sure it's not frozen into the crank (Been off recently for impeller) ??<br />Wiring and water cover corrosion are issues with old Mercs in salt, but generally the '76 3 cyl is a pretty common and popular motor. Ed Mc knows his Mercs and his advice is always spot on. As far as "Getting to plane" I don't know what a "1650" is, but my 14ft F/glass (heavy halfcab) will run at about 28 knots and plane nicely with 2 on board with my 1980 50 4 cyl.You might want to whack a foil on it.<br /> http://www.myfishingpictures.com/watermark.php?file=527/1413caloundra-5-med.jpg

 

[JasonJ]

Re: old 76 merc

On a 16.5 foot fish and ski (I assume thats what your f/s means), you'll need to prop it correctly. It may plane, depending on how much deadrise it has. If the hull has minimal deadrise, you'll be okay, but if it has a good amount of deadrise, it'll struggle to get on plane. Is there not any other motors around, maybe something closer to what you had in power?

 

[phatmanmike]

Re: old 76 merc

you cxan plane easily with that motor. i can plane my 16 center console with my 1972 50hp twin.<br /><br />that year merc is excellent motor, dont let these hater's bring you down! mercs are MUCH lighter than those OMC motors, so your pushing less weight, albeit not much, but every lil bit helps.<br /><br />parts are ungodly easy to come by. i have mercs and evinrudes. they are both the same in easyness of getting parts and service.<br /><br />my big 115 merc , along with many others, dont have cylinder heads. its all ONE PEICE. i dont know for sure about the 65hp model.this can be good or bad, depends how you look at it.<br /><br />just be smart, take your time, check the compression and repost any more questions you have.

 

[procraftmark]

Re: old 76 merc

thnx a million guys!<br /><br /><br />mark