Johnson 9.5hp twin overheated

[Cyberfly]

I ran my little 9.5 this weekend for a short trip. Started out good and ran it for about 30 minutes. On the way home it started smelling hot and then stopped running. It didnt seize up or get stiff, but now it wont run at all. It feels like it has good compression. Has a fairly good spark and good plugs and I know it is getting gas. So what would cause the motor not to run??????? Is it now a boat anchor instead of an outboard??? Man I loved that little motor, cause it was so light and peppy.... thanks ron.

 

[mikesea]

Re: Johnson 9.5hp twin overheated

you need to do a precise compression ans spark test,what looks like good spark,may not be,it should jump a 7/16 gap with a good blue spark,and the spark should be at every cycle,you may not be getting spark every cycle,the fact the motor got hot,would lead me to think you may have coil problems hat are producing less than perfect spark,or,your compression may be to low,you need to screw a comp.guage in each cyl.and compare results,overheating often leads to blown head gasket,what your comp.should be,I dont know exactly,but as long as its (guessing)say 85 or higher and most IMPORTANT both cylinders are about 10 lbs the same ,with GOOD spark and fuel it should run,you then need to find the overheat problem,which most time is impeller failing due to age,or floating object blocking water intake,keep us posted so others learn

 

[F_R]

Re: Johnson 9.5hp twin overheated

The above is good advice, but 7/16" spark is expecting a mite much for the magneto system. 1/4" is reasonable.

The compression test is first on the list of to-do. If the paint is burnt, you have gasket problems, compression or no. And the exhaust gaskets on that motor are not the easiest things in the world to change. You also very well may have burned up the shift rod seal, listed as no longer available. It will smother out from smoke under the hood if it is burnt.

There has to be a moral to this story, huh?

 

[Cyberfly]

Re: Johnson 9.5hp twin overheated

Well the paint is missing on the back of the motor around the spark plugs, and the compression is about 45 lbs and 38lbs respectively top and bottom cylinder. The lower unit leaks when I leave it in the water for more than a couple of days and the cover is cracked and broken. Nough said.

The moral to this story is that I might be using the 9.5 as a new fish attracting reef in the middle of the lake. Some of my neighbors and I built a fish reef that is made up of some old broken concrete that we carried out on my pontoon boat several years ago. We carried about 2 tons of it out and put it in 45ft of water. The 9.5 may be the crowning jewel for the top of the pile. I can put the lower unit in a 5 gal bucket and fill with readymix and drop it over...Im also a scuba diver and may take it down and place it at it's final resting spot.. seems like a fitting end to the old motor. Will be buried at sea where it belongs....thanks for the help.

 

[Rick.]

Re: Johnson 9.5hp twin overheated

That's a drag for sure. Before you send her to her final resting place I have to ask have you ever thought of using her as an organ donor? I have a 73 and parts are getting harder to find. Rick.

 

[ezeke]

Re: Johnson 9.5hp twin overheated

The cylinder head gasket may well be the reason for the low compression readings. While the gasket is a little bit of a pain, it should not stop you from trying it. It is way easier than changing one on a 9.9 or 15.

If you want to give up on it, the motor is just light enough and short enough to ship by UPS, so I would suggest that you list it on EBay for parts. It should bring you at least $100. US.

 

[Cyberfly]

Re: Johnson 9.5hp twin overheated

Good advice, maybe Ill reconsider using it as a fish magnet. Can I sell on this forum??? Let me do some checking and see if my local outboard mechanic wants to give me fortune for it,, if not Ill sell it cheap to someone that can recycle it..Ill keep you posted,,thanks for the help.
This is the best forum Ive ever used,, you guys are really active and help novices like myself a lot..thanks ron