1995 75hp 80 cu in mercury

[Arkansas river rat]

Looking for advice , Thinking about having another project. This motor has tiller t-n-t but has been overheated scoring all cylinders. For around $800 I can get this motor $700 for complete rebuild kit and plus the machine work would this motor be worth rebuilding? I know this motor is the same as the 90hp but with different carbs and reed block. I don't know if its a good motor or not to have.

[champ20B]

Looking for advice , Thinking about having another project. This motor has tiller t-n-t but has been overheated scoring all cylinders. For around $800 I can get this motor $700 for complete rebuild kit and plus the machine work would this motor be worth rebuilding? I know this motor is the same as the 90hp but with different carbs and reed block. I don't know if its a good motor or not to have.

I wouldn't invest that much in that motor. It is 20 years old and damaged at only a 70hp. It might be worth $300.00 with the suspicion that there could be more wrong with it. Even as a parts investment, what you cant see is always a gamble, and there are a lot of parts you cant see unless you buy it completely disassembled for a inventory/condition parts evaluation.

[Arkansas river rat]

I appreciate your opinion. I thought it might be worth the build cost versus buying a new outboard and wanted other peoples opinion .While building it I was going to make it a 90hp carbs and reed change. How reliable are these motors

[champ20B]

I appreciate your opinion. I thought it might be worth the build cost versus buying a new outboard and wanted other peoples opinion .While building it I was going to make it a 90hp carbs and reed change. How reliable are these motors

These engines are o.k if you can get one real cheap.......but I wouldn't want to go over $1000 total to get it right, if I was doing all the work too. The best engine would be an OMC 3 cylinder or a V-4 90++ hp. You can find one of those for no more already running and a heck of a lot better. Mercs kind of went to pot metal quality after 1958. They started using cheap quality metals that was more prone to cracking and corrosion. They clatter and rattle and are noisy critters. In the later years, the Japanese (who do make good stuff) built some merc engines and those are o.k, except for the 25hp. Some of those had those infamous chrome cylinders like the 25XS racing motor and that wasnt good in any engine. This was in the mid 80s till the 1990s. Now days, anything they make under 70hp is made for them in China. The Mercury is something I would just pass up. I am going to build a 20cid merc though, for something to run A-Mod and/or for hard running boat-hull testing, just to run it till it breaks. That is all those are good for!!

[HankFrazier]

These engines are o.k if you can get one real cheap.......but I wouldn't want to go over $1000 total to get it right, if I was doing all the work too. The best engine would be an OMC 3 cylinder or a V-4 90++ hp. You can find one of those for no more already running and a heck of a lot better. Mercs kind of went to pot metal quality after 1958. They started using cheap quality metals that was more prone to cracking and corrosion. They clatter and rattle and are noisy critters. In the later years, the Japanese (who do make good stuff) built some merc engines and those are o.k, except for the 25hp. Some of those had those infamous chrome cylinders like the 25XS racing motor and that wasnt good in any engine. This was in the mid 80s till the 1990s. Now days, anything they make under 70hp is made for them in China. The Mercury is something I would just pass up. I am going to build a 20cid merc though, for something to run A-Mod and/or for hard running boat-hull testing, just to run it till it breaks. That is all those are good for!!

Whatever

[MWhite]

These engines are o.k if you can get one real cheap.......but I wouldn't want to go over $1000 total to get it right, if I was doing all the work too. The best engine would be an OMC 3 cylinder or a V-4 90++ hp. You can find one of those for no more already running and a heck of a lot better. Mercs kind of went to pot metal quality after 1958. They started using cheap quality metals that was more prone to cracking and corrosion. They clatter and rattle and are noisy critters. In the later years, the Japanese (who do make good stuff) built some merc engines and those are o.k, except for the 25hp. Some of those had those infamous chrome cylinders like the 25XS racing motor and that wasnt good in any engine. This was in the mid 80s till the 1990s. Now days, anything they make under 70hp is made for them in China. The Mercury is something I would just pass up. I am going to build a 20cid merc though, for something to run A-Mod and/or for hard running boat-hull testing, just to run it till it breaks. That is all those are good for!!

Mercury outboards motors used to be the best motors out there, (2stroke motors). Them 4strokes motors i dont care for though.

[champ20B]

Mercury outboards motors used to be the best motors out there, (2stroke motors). Them 4strokes motors i dont care for though.

Yes, the old green mercs did give reliable starts and were fast running in their time. They could even idle and plane up a jon boat on one cylinder! That happened one time with mine. One thing about the older mercs versus later, A mark-25 was a 20cid and was just as strong as the later merc-200 even though that was 22cid and had a much larger carb and reeds. Me and a friend compared the two on a lake about 8 years ago.

As far as good engines from way back though, I have admit that I found 1940s-1960s OMC, McCulloch/Scott, and even some old off the wall brands that were running or could be made to run with very little effort that were badly tattered, sat up, and never restored. But if its a Merc over 30-40 yrs old "that sat up", it will need to be completely rebuilt guaranteed to avoid destruction every time, even if it aint stuck.

I have a 1961 McCulloch 7.5hp that was a rough looking old survivor. I looked through it and the internals and all controls was in such good shape, I got it running perfect in a days work for about $80.00, after buying replacement coils and impellers. I have and still use it after over 20 years that I've had it without fail. It is super smooth, reliable and very quiet. It makes a full 7.5 ponies at only 36lbs and has full gearshift with a bailer pump handy for that leaky aluminum boat. Their weedless shearing prop design actually does its job as it was advertised in the day. It has to be the best utility fishing motor under 10hp ever designed in history. No one has ever before or since made a carry about fishing outboard with the kind of power to weight and other features that this low profile model had. It is just unbelievable. By 1966, this model was advertised as requiring 100:1 oil/fuel mix....Talk about ahead of the times! McCulloch actually had their own brand of 100:1 two cycle outboard oil back then one could buy. Its a shame that they quit making outboards so long ago, but they were just to far ahead for what the public wanted I suppose.

[Fastjeff57]

I'm not about to get into a pissing contest on old Merc quality, but that new type, Yamaha based 80 cube triple, does have a good reputation. That said, they do seem to score cylinders rather often, possibly due to the oiling system.

Regarding those old, V-4 OMCs, we had one of those on our USCG Auxiliary patrol boat, and what a gas sucking,, rough running piece of dog poop it was. A half decent, clapped out in-line Merc six banger would put it to shame.


Jeff

PS: I run the hell out of early '80s Merc triples--that "infamous" motor--and have yet to experience a failure.

[MWhite]

I'm not about to get into a pissing contest on old Merc quality, but that new type, Yamaha based 80 cube triple, does have a good reputation. That said, they do seem to score cylinders rather often, possibly due to the oiling system.

Regarding those old, V-4 OMCs, we had one of those on our USCG Auxiliary patrol boat, and what a gas sucking,, rough running piece of dog poop it was. A half decent, clapped out in-line Merc six banger would put it to shame.


Jeff

PS: I run the hell out of early '80s Merc triples--that "infamous" motor--and have yet to experience a failure.
Them old mercury motor are some of the best motors mercury ever made, I still see people running them without any problems. Its all in how u take care of the motor, whether its a merc,Yamaha and so on, if u abuse them and don't keep up the maintaince on them they'll leave u paddling. They all tear up.

[Fastjeff57]

Well said, brother!

Jeff