OMC Questions you motorheads
 

As yall seen my new boat photos I posted I now own a REALLY clean low hours 60HP Johnnyrude.


While I dont for see any real maintenance for some time I was just wondering what might I expect for a rebuild to set me back doing the labor myself?



Im not sure the exact year its mid to late 90's I think?

This is a boat Lord willing Ill never get rid of so just curious.


Also, is there anything I can do to take this one to 70HP?

That probably is the old 70 hp Johnson. Lost the 70 rating when they went to prop shaft hp. in the late 80's. What you have is the 3 cyl 3 carb they are tough as a cut nail.

depends on what needs to be replaced, sorry for the empty answer, but depending on whats damaged inside will make a major difference, last one I did, I charged $1800

i have also found in-line 3 cyl don't like to idle , so don't spend a lot of time & money trying to get it silky smooth.

I have yet to see an OMC looper that likes to idle really good. As far as rebuild costs, it's a crap shoot as to what all it will need when you do it. A basic kit will set you back probably $450-550 plus machining, but if there is any other damage it can get REAL costly. As far as making it a 70HP, I'm sure it's doable but I believe you have to pull the powerhead off and modify the tuner can and swap the carbs. Some also used different cylinder heads and exhaust timing to get the extra oomph.

Thanks guys, it is the 3cylinder I didnt know that about the older 70's. Always thought this one looked identical. Im wont ever open it up till it needs it. It does idle pretty good though once it warms up.

there were some cooling system mods on those 3cyl engines, you remove hte piss hose from the exhaust plate and move it to the top of the block, if it doesn't have a tapped boss for teh hose fitting, you need to drill and tap it for the fitting.

OMC made that same basic 3 cylinder since 68 when they came out with the first 3 cylinder loopers. The engines have seen alot of improvements over the years, but the basic design remains the same.

I have know this one for about 5 years and its always been solid as a rock and super dependable. I hope it keeps on for me!

My old boat had the 1981 70 hp. Boat sank in freshwater at my dock after a HEAVY rain (and a leak LOL). Long story....but the short of it was that after getting it up and out I poured lots and lots of marvel mystery oil in the cylinders and worked it in real good, turning the flywheel by hand and blowing it out....then doing it again....and again. Toward the end I started hitting the starter to blow it out. Finally, put the same plugs back in, some fresh gas...fired it up....filled the yard with smoke....and the neighbors yard....and their neighbor's yard. After a few minutes, when I could see the engine again, she was purring. Pressure washed the boat and ran it for 2 or 3 more years and never had problem with it. Oh, and fixed the leak!

Cannot brag on those motors enough.

Run GOOD oil in it, ditch the VRO if it has it still and premix it, and run ethanol free fuel and it should run for a LONG time still. Just make sure to decarb it as the biggest killer of 2 strokes is carbon buildup that causes a ring to stick.

what he said X a billion

i have had a old 70 jonno and the connecting rod bolt came loose and destroyed the engine ---i also have a friend the same thing happen to it both these engines were never touched from new---i was thinking the bolts may of strecthed or rods anyone have an answers

You normally only hear of this in engines that were rebuilt and the rod bolts re-used.

most of the time I've seen the rod bolts stretched or the rods broken, the piston had seized, causing the rod failure, Was it on the middle cylinder? I do know the two cylinder 40-55 hp had a history of rod failures(and lower unit issues)

What you you mean "decarb" it?

Google "Dunk's decarb method"

you can use mercury power tune or do a shock treatment of Yamaha ring free(or mercury carbon guard)