1971 johnson 50hp will not plane out !!!!!!

[beau123]

Check compression,<br />My cousin has a seahorse 35h.p. and he used to could pull a hydroslide. His compression was an even 120psi. His wife's grandfather run it hot one time, and the next time he tried to pull the slide, he notice that the boat was stuggling to pull it. He brought it to me, ran a comp. test and it was around 60 psi. So it might be due to low comp..

 

[mikeperry]

1971 johnson 50hp will not plane out !!!!!!

I have a 13ft. tri hull with a 1971 50hp. johnson HYDROELECTRIC SHIFT..The engine purrs like a kitten.Everything works like it is supposed to at home , Shifts into reverse&,Forwards just fine, but when i put it in the water it doesn"t have enough power to get up on plane.It has new plugs,Bat.cables,selenoid,impellar, and i removed & cleaned both carbs. The BOAT is around the same age.It is rated at 65hp. 4 people or 700pds. Can lower unit oil be causing the problem? Can not find type C oil.... Please help NO CLUE !!!

 

[b.gagnon]

Re: 1971 johnson 50hp will not plane out !!!!!!

There are many things to check. What is your rpm at full throttle? Also if that motor was off another boat it could have the wrong pitch prop on it. That should be plenty of power for that size boat.

 

[ddaigle]

Re: 1971 johnson 50hp will not plane out !!!!!!

Also, make sure the boat isnt full of water or waterlogged foam under the floor. This can happen in older boats. I had one that would dry out and run great until it rained or sat in the water then it would gain about 700 pounds of weight and barely plane.

 

[ED21]

Re: 1971 johnson 50hp will not plane out !!!!!!

I don't know anything about hydroelectric shift, but have you checked shear pin or hub to be sure prop isn't slipping.<br />Has it ever planed out the boat?<br />The previous comments sound right too.

 

[mikeperry]

Re: 1971 johnson 50hp will not plane out !!!!!!

 

[mikeperry]

Re: 1971 johnson 50hp will not plane out !!!!!!

My boat is sort of heavy. Maybe there is nothing wrong with my engin. My prop is a 13 1/4 x 17 . IT looks as to be the original. Also the engin turns well over 5,000 RPM's. When trying to plane the prop boiles the water 8 to 12 inches high behind the engin.The boat also leaves a big wake.Thats what leeds me to beleive that you maybe wright.I would still like to know about this type C footing oil??????? THANKS EVERYBODY

 

[ledgefinder]

Re: 1971 johnson 50hp will not plane out !!!!!!

It may shift better with Type C, but that has nothing to do with why your boat won't plane. <br /><br />Sounds like a spun hub, if you're sure it's spinning over 5000 rpm.

 

[ddaigle]

Re: 1971 johnson 50hp will not plane out !!!!!!

You may have the motor trimmed too high and are cavitating on take off. If your front end go's way up and the motor revs high, you have the motor tilted to far up or your prop hub is spun. If you have power trim the motor needs to be all the way down for takeoff, if no pwer tr. you may need to adjust the pin that controls this. Also, where is your anti-cavitation plate( flat plate directly above propeller)in relation to bottom of boat? higher, lower, even with?

 

[mikeperry]

Re: 1971 johnson 50hp will not plane out !!!!!!

Sorry that i havn't responded lately.Went to lake to run boat.It got up on plane for the first time,It was all going fine for about 3 min. when all of a sudden it starts acting like it is jumping out of gear.It only does it at high RPM.What could be causing this new problem??? I slowed it to an idle & took it back to the dock.Didn't want to damage it.Also i changed the L/U oil,It seemed to be the proper fix to the first problem.I need the wiring diagram for the FOR.REV. switch? THANK YOU all for your responces!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[CATransplant]

Re: 1971 johnson 50hp will not plane out !!!!!!

That last symptom sounds very much like a spun hub on the prop. Remove the prop, and mark the prop and hub with something waterproof, like a Sharpie pen, then re-install and try it again.<br /><br />If the marks don't line up after your WOT run, then the hub is slipping. That can sound just like the lower end slipped out of gear.<br /><br />The prop can be repaired. Another answer is to try a spare prop that is known to be good. Since I believe every outboard owner should have a spare prop in the boat, along with the tools needed to change it, then maybe this is a good opportunity to acquire that spare prop.

 

[karrick]

Re: 1971 johnson 50hp will not plane out !!!!!!

If you are still curious about the lower unit fluid, you need to run the type C or premium OMC lube. The viscosity is different than the regular fluid which allows it to work better with the shift mechanisms. I'm not saying this would cause you problem, just clarifying your question.

 

[mikeperry]

Re: 1971 johnson 50hp will not plane out !!!!!!

Went to lake today to run boat , But forgot boat keys at home!!!! HA HA HA... Bad day at lake.. Maybe next time i can run it...