1983 Johnson 50hp - fix or replace?

[walt501]

In 22 years this motor has never had a repair, with the exception of replacing the fuel lines because of alcohol in the fuel in later years. But after a month fishing in Ontario, at full throttle it would seem to jump out of gear (shift dog?). If I stayed under full throttle it wouldn't do it. Here's my question, would you fix this engine, or replace it? Engine compression is good 140 over 135. I'd like to keep the cost down, but a new engine isn't out of the question since this one has plenty of miles on it. Is it possible to find a newer 50hp two stroke Johnson with a tiller handle? I've looked and can't find one with a tiller. I want the most hp possible for the least amount of weight. 50hp is the max that my boat is rated for, as that was the largest tiller motor made in 1983. I contacted the boat manufacture, and they will not certify it for a higher horsepower. Suggestions?

 

[lark2004]

Re: 1983 Johnson 50hp - fix or replace?

When it jumps out of gear, does it stop accelerating and the revs pick up, or does it go BANG? like it hit something?

 

[djzyla1980]

Re: 1983 Johnson 50hp - fix or replace?

In 22 years if you have only replaced the fuel lines.... you doin good. If you buy another used motor...you may very well have issue on top of issue. You know the exact history of this motor. I wouldn't chance that over a new used one.<br /><br />I would find out if it's actually the clutch dog, could me spun hub.

 

[G DANE]

Re: 1983 Johnson 50hp - fix or replace?

Sounds like a spun hub, starting to slip, usually a clutch dog keeps jumping, once started. Draw a line with a speedmarker from propshaft over hub edge to prop hub. Take a run till it slips once, stop and see if hub has slipped. If it has, its an easy fix, get it to a propshop and they will rehub it for 50 - 75 $ usually, as I'v heard prices are with you.

 

[lark2004]

Re: 1983 Johnson 50hp - fix or replace?

thats what I was getting to with my question, yet to hear an answer

 

[umblecumbuz]

Re: 1983 Johnson 50hp - fix or replace?

Not an answer to your question, but ...<br /><br />A few new posters sometinmes get the idea that Johnnyrudes are nothing but trouble, because most people post here seeking advice. <br /><br />It's good to see the other side of the coin. 22 years without evn a WATERPUMP? is good service. And there's plenty more out there like that.

 

[walt501]

Re: 1983 Johnson 50hp - fix or replace?

Thanks to all for your help. To clarify, it goes BANG, feels just like I hit something underwater. It did it 3 times in a row on full throttle - in 50 feet of water, so I'm not hitting anything. Also, when I'm at 1/4 throttle or less, it seems like the boat now wanders, it won't hold a straight course. It slowly goes left, then corrects to the right, then back again over and over. I don't recall it doing that in the past.<br /><br />With regard to replacing the motor, I wouldn't go with a used motor. I would only be interested in a new 50 hp. I was thinking a close out Johnson 2 stroke, as it looks like they have been dropped from production, but I haven't found one on-line. Any sources I'm missing?<br /><br />Just to be clear, in 22 years the fuel lines where the only thing I have touched on this motor besides new spark plugs and changing the lower unit oil. It has started and run perfectly with the exception of the most recent problem. It would even troll ALL DAY on lake Michigan years ago without loading up and dying - usually 8 hours per day of trolling. It will still do it, and I've never touched the carbs (probably should rebuild them ! My family has always had good luck with OMC products, going back to my Dad's 5hp that my Mom got him for his birthday in 1955!<br /><br />Again, thanks to all for your suggestions. I hope the information I've added will clarify the problem for those more experienced in these things. I look forward to your response!

 

[jleus]

Re: 1983 Johnson 50hp - fix or replace?

If you have any mechanical ability stick with what you have and start a list of needs to get the unit back to top shape. IT IS hard to believe that the thing has not had a water pump rebuild in that many years, I would not run it another moment without a new one, or you might be looking for a new motor because this one is ruined. If you work on your own, you will not beat the simplicity of that motor with a new one. Parts will always be available. Clutch dogs are available and not to bad to install. If you hire your work done, that changes the story only slightly to me. Parts wear at the same rate, no matter the year of the motor. If reasonably well cared for these things last literally forever. <br /><br />Sidenote:<br />OMC boards / chatrooms are full because there are so many JohnyRude motors out there. They basically had the "portable" market cornered for about 25 years as I see it.

 

[Goodoleboy]

Re: 1983 Johnson 50hp - fix or replace?

Your clutch dog is slipping. On some motors you can turn it around so it now running in reverse.<br /><br />Which as you know takes lots less power. If it were me I would buy the old girl a new one. ...Bout 75 bucks or so. <br /><br />And ofcourse freshen up the water pump. Your gona spend around 150 bucks for new parts if you do all the work your self. <br /><br />If you have it done at a marine shop look for close to 500 to 750 for same.<br /><br />If you trade it in for a new one....they wont give you squat for it.<br /><br />Save it...sooner or later some dummie like me that likes tinkerin around in the winner time mite give ya .....Oh ...I dont know.....Mabeeeey ....uh hunert fur it....Grin.<br /><br />Ball is now on your end of the court!<br /><br />Good luck!

 

[ob15]

Re: 1983 Johnson 50hp - fix or replace?

I wish my motors were like your's. Sounds like the clutch dog is shot and needs to be replace. Even if you had to replace the forward gear, you will spend much less than a new motor. I would also start doing some routine maintenance (water pump, carbs, etc.). I wouldn't hesitate to hang on to the motor.

 

[fireman57]

Re: 1983 Johnson 50hp - fix or replace?

I'll pay shipping if you send it to me. Put the parts in that need replacing and you will feel like you have a new engine. It has been trustworthy all these years and I don't think she'll let you down for a while with a little TLC.

 

[walt501]

Re: 1983 Johnson 50hp - fix or replace?

Thanks for all your help! I guess my next steps from what I've read here is to get a parts manual and service manual for my engine. I've also read on the forums about disconnecting the shift linkage at the powerhead to remove the lower unit. I've replaced a water pump impeller before on another engine, but never actually dug into the gears. Hopefully, the service manual will walk me through it. I assume I should replace the water pump, all seals, shift dog, and possibly the forward gear. Any other pitfalls? I have a fairly good set of tools, but no specialized OMC tools. With your help, hopefully I can get this done. I'm sure I'll be checking back again for assistance.<br /><br />Thanks again for all your help, let's see if we can keep this Waukegan Wonder running!

 

[fireman57]

Re: 1983 Johnson 50hp - fix or replace?

I would not get a Seloc or any other manual except an OEM manual. They have better explanations and pics plus shortcuts and tips. The only problem you might run into is the drive shaft may be stuck in the powerhead but by doing a search on that there are plenty of threads with help. Good luck and keep us posted.

 

[lark2004]

Re: 1983 Johnson 50hp - fix or replace?

try Ken Cook for the manuals, they have reprints of the original factory manuals.<br /><br />I agree with fireman57, you might have a problem with the driveshaft. <br /><br />The prop may also be a bit of a problem. If it hasn't been off before, it may be stuck on the splines of the propshaft.<br /><br />Other than that, you should be OK.

 

[lehmicke]

Re: 1983 Johnson 50hp - fix or replace?

A friend of mine is looking at buying an 83 Johnson 50 horse from a neighbor, and we want to run a compression test before buying.

My questions are:

1. What spark plug does it take (have to see if my compresion tester is the right size)

2. What would be an acceptable compression for this used motor? should all cylinders be within 10 PSI of each other?

Thanks,

Mike