# 1964 johnson 9.5 wont run right with the cover on it



## littlechub (Apr 30, 2012)

my johnson 9.5 is giving trouble. it will not run out on top end with the cowling cover on, pull it off and it runs perfect. ive checked and double checked to make sure nothings being pinched by the cover and even ripped some of the foam out of the inside of cover to make sure its not smothering the carb. any idea where this motor is supposed to draw its intake air from? it acts like its starving for air?


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## lovedr79 (Apr 30, 2012)

Check for wasps nest or mud dobers nest. Prolly something stuffed in the holes on the lower motor cover.


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## cajuncook1 (May 1, 2012)

There are four known exhaust leak issue with the 9.5hp Johnson/Evinrude series motor from 1964 to 1973.

Here is a digital parts diagram of your motor and for ordering parts.

https://www.marineengine.com/parts/vintage-evinrude-johnson/380046/catalog.html?https://www.marineengine.com/parts/vintage-evinrude-johnson/380046/38004600001.htm


1. Is the *exhaust housing seal*. (Trash or debris could be lodged under between the rubber seal and the wall of the motor exhaust house cover. With a flashlight you can look under the motor or put the motor on its side and visualize the exhaust housing seal.) Worst case you will have to drop the lower unit to inspect the seal. 

*** It could be damaged or miss-shaped over the years.

2. Is the *exhaust hose*. Could be dried and cracking or torn but not visually seen. With the motor cover off and the motor running, take a bit of soapy water and pour it over the hose to see if bubbling occurs, kind of like checking for a leak on a bike or auto tire. 

3. Is the* shift rod boot*. (bad news is this part is NLA (no longer available)

** Some have tried to repair it using hardening high tempered gasket sealer. (Make sure it is fuel/oil proof and high temp resistant. I have been told they apply the sealant around the boot to seal up the tear or breakdown. *** I have not tried this so I can not attest to its success, but have heard from experience tinkers that this sometimes works. No guarantees....but if that is the source then you don't have much to loose except running the motor without the cover. 

4. Impeller housing and drive shaft *(washer and seal)* The washer and seal together help prevent exhaust gases from ascending above the exhausting boot in the motor cover area. These are parts are often missing or worn, because people don't realized there purpose.


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## lovedr79 (May 1, 2012)

Wow! Thats an excellent thought. Much better than mine. I had a jetski that split and exhaust boot leaving me stranded once.


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## littlechub (May 1, 2012)

i appreciate the responses and the help, thank you.


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## WhiteMoose (May 1, 2012)

I had an early 70's Johnson 9.5 that the previous owner had drilled all sorts of vent holes into the cowling. I guess this was why!


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## lovedr79 (May 1, 2012)

Is the cover metal? If so could the cover be grounding out the plug.


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## cajuncook1 (May 1, 2012)

lovedr79 said:


> Is the cover metal? If so could the cover be grounding out the plug.




The cover is made of fiberglass or similar material.

With the cover on, exhaust gases accommulate under the hood(if there is an exhaust leak), so yes you are right it is starving for air (Oxygen). Once you remove the cover it runs much better. Classic symptoms of an exhaust leak issue.


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## lckstckn2smknbrls (May 1, 2012)

cajuncook1 said:


> lovedr79 said:
> 
> 
> > Is the cover metal? If so could the cover be grounding out the plug.
> ...


+1


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## jladdsmith (May 2, 2012)

+2, I have the same motor and mine won't run in a barrel (even with the cowling off) without a fan on it. I heard it had something to do with the low profile design of the motor. Works fine on the river.


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