Should I rebuild my 1970 9.5 Johnson?

[John Lapic]

I came across a 1970 Johnson 9.5. It has not been used for 5 years, only 3 times a year prior to that and has been garaged. It is used in fresh water. I know quite a bit about car engines but have never torn into an outboard. I plan to get a service manual, but want to know if I am in over my head to tear into this outboard?

What standard items should I plan to replace, such as seals and bearings? Are parts still available for most repairs?

Tell me what to look for and what to look out for.

Thanks

 

[Rick.]

Re: Should I rebuild my 1970 9.5 Johnson?

Go Slow here. First thing I would do is clean it up a little, squirt some outboard oil in the cylinders and let it sit for a couple of days and then do a compression test on it. There is a good chance you don't have to any rebuilding on it. If the compression checks out fine then look at the FAQ thread and look to a heading about maintaining a motor that has been moth balled for a period of time. If it was running fine when it was put away you should have it up and running again with a minimum of expense and time. Enjoy and good luck. Glad to see you have ordered the manual. Rick.

 

[samo_ott]

Re: Should I rebuild my 1970 9.5 Johnson?

What Rick says is bang on. Do a compression check first, that's the biggest indicator on whether to rebuild or not. If you have good compression then tune up parts are relatively cheap to get and install. Repost once you have done a compression check. And remember, both plugs out, throttle open and pull several times per cylinder to get a good reading...

 

[guy74]

Re: Should I rebuild my 1970 9.5 Johnson?

I have a 1968 Johnson 9.5 hp, it was left in a shed for over 5 years before I got it. All I had to do to it was replace the fuel pump, and kill switch (a rat chewed them up), cleaned up the points and carb, and replaced the impeller. It ran pretty good right off, I then decarbed it. I ran it on a 16' flat bottom john boat it would push me (300lbs) and my uncle (250lbs) at around 18 mph, which I thought was pretty good. It would get the boat up on plane then I could maintain 15 mph at around 3/4 throttle. BTW the compression on it was right on 85psi on both cylinders.

 

[tashasdaddy]

Re: Should I rebuild my 1970 9.5 Johnson?

that motor is just broken in. not even a teenager. there are a lot of the 1950's motors still in service without a rebuild.

 

[wbeaton]

Re: Should I rebuild my 1970 9.5 Johnson?

To be honest, if it was mine I would squirt some oil in the cylinders, check for spark (clean/set points and replace spark plugs if necessary) and then try to run it in a barrel or muffs.

If it won't start after that, then I'd start troubleshooting. Your history of the motor suggests it ran fine 5 years ago. Doesn't sound like you have any reason too believe it won't run fine now.

Also, you will definately need an impeller. My official stand is that you must change it before running that motor.

 

[Hoss the Hermit]

Re: Should I rebuild my 1970 9.5 Johnson?

No, it's junk, send it to me and I will dispose of it for a minimal charge. Seriously, it's a real nice motor, get a manual and go for it. What else are you gonna do all winter?

 

[John Lapic]

Re: Should I rebuild my 1970 9.5 Johnson?

Why does everyone seem to tell me to replace my impeller? Why is that important?

 

[Rick.]

Re: Should I rebuild my 1970 9.5 Johnson?

It's an "ounce of prevention/pound of cure" thing. The impellers do wear out and sitting for a long time they can get brittle or cracked. If it fails it will ruin your day in a best case scenario or ruin you motor in the worst case. You probably won't notice it isn't pumping until the motor stops from an overheat situation. Once you have replaced it, you will know the history regarding when it was replaced and approx. how many hours/years before you need to do it again. This poses an interesting question though. How often should it be replaced? I don't have an answer for that. Rick.

 

[HighTrim]

Re: Should I rebuild my 1970 9.5 Johnson?

For the price that you would pay for a new one, why would you go more than 2 or 3 years without changing it. Cheap part but its failure causes catastrophic consequences. Regualar maintainence such as this will prevent future expensive problems down the road. Changing the impeller and rebuilding the carbs every 3 years is probably a good habit to get into on off years so one year you're doing the water pump, one the carbs. Maintainence like that will prevent troubleshooting, which I think is the hardest part of working on outboards, the act of replacing the part is the easy part. Others will have better input on this though.

 

[Thumper2442]

Re: Should I rebuild my 1970 9.5 Johnson?

Another reason to replace the impeller.........when it gets brittle it can send small pieces into the powerhead, plugging some holes where water is supposed to flow.

 

[EricR]

Re: Should I rebuild my 1970 9.5 Johnson?

I just spent five hundred bucks on my 45 horse Honda because I put off changing the impeller, it failed ON THE FLUSHER, the engine was shut down before it got hot, but a tiny piece of rubber got lodged in the end of the water tube from the pump up in the powerhead, I was convinced it was NOT an overheat but rather a problem with the electical end setting off a false alarm. I gave up and took it to a guy that worked on Hondas. He had to pull the powerhead, involving torch heating a bunch of corroded hardware to get it out, the motor had seen lots of saltwater use before I got it.

Anyway, long story short, an impeller's about twelve bucks, just change it and be done with it.

 

[samo_ott]

Re: Should I rebuild my 1970 9.5 Johnson?

Those dang Japanese engines!