Problems with a 6 hp Johnson

[terry32506]

Hello, I have one of the older 1977 6 hp Johnson motors and the problem I am having is when I run it without the cowel hood all is fine , she revs out to max, lots of power however once I put the hood back on she runs sluggish, reduced power on wide open throttle...It seems to me its an air flow problem, or I think it is. I have replaced and rebuilt the entire fuel system and carburetor as well as replaced all fuel line hoses, vacuum hoses, plugs etc.. This has me baffled thats for sure...As I am running the motor and slowly remove the hood the problem doesnt go away until the lidt is nearly completely off..Strangest thing I have come across and it doesnt matter if I run the motor in a tank or on my boat the same thing occurs.

Anyone have some ideas of what might be going on?


Terry

 

[tashasdaddy]

Re: Problems with a 6 hp Johnson

exhaust leak between head, and midsection. they do not like breathing their exhaust, any more than we do.

 

[cajuncook1]

Re: Problems with a 6 hp Johnson

Welcome to Iboats,

Your condition seems like a exhaust leak problem. Exhaust leaks are common for the the Evinrude/Johnson 9.5hp from 1964 to 1973. But as you clearly state that you have 1977 6hp.

Did you have to remove the power head from the exhausting assembly? If you did, did you replace the exhausting gasket between the power head and exhausting assembly? Because if the exhaust housing gasket is torn or leaking that could be your source of built up exhaust and the need to remove the cowl in order to for motor to get adequate amount of oxygen and not re-breath its own exhaust. Look at the link.

http://www.boats.net/parts/search/BRP/JOHNSON/1977/6R77M 1977/EXHAUST HOUSING/parts.html

parts 1 and 79

Another possible area could be a leaking gasket from the exhaust outer or inner covers located on the tiller side of the motor. Again causing the same situation as described above. Look at the link.

http://www.boats.net/parts/search/BRP/JOHNSON/1977/6R77M 1977/CYLINDER & CRANKCASE/parts.html

parts 27, 28,and 29


I'm speculating here, but I'm sure one the forum's GURU's will chime in a give a experienced perspective.

Good luck, I hope you are able to figure it out. Nice little motors, I have a 1967 model.

cajuncook1

 

[cajuncook1]

Re: Problems with a 6 hp Johnson

Sorry TD, I guess I was typing my write while you responded! I blabber with too much detail, I need to be more direct....lol it would be quicker!

cajuncook1

 

[kenmyfam]

Re: Problems with a 6 hp Johnson

I'm with the exhaust leak as well. Unless the plug wires are grounding out on the hood.

 

[terry32506]

Re: Problems with a 6 hp Johnson

I'm with the exhaust leak as well. Unless the plug wires are grounding out on the hood.

Thanks for all of your input guys and the links, im leaning towards the exhaust leak. Interesting what you said about the plug wires grounding out, my dad and I were having a look and he mentioned that..Even though the hood is made of fiberglass that can cause a ground out?

 

[BigB9000]

Re: Problems with a 6 hp Johnson

Thanks for all of your input guys and the links, im leaning towards the exhaust leak. Interesting what you said about the plug wires grounding out, my dad and I were having a look and he mentioned that..Even though the hood is made of fiberglass that can cause a ground out?

psssshhhhhh No.


Unless it moves the wires closer to the block, causing it to ark/arc/spark

 

[kenmyfam]

Re: Problems with a 6 hp Johnson

psssshhhhhh No.


Unless it moves the wires closer to the block, causing it to ark/arc/spark

Or a boatload of moisture in there.

 

[terry32506]

Re: Problems with a 6 hp Johnson

psssshhhhhh No.


Unless it moves the wires closer to the block, causing it to ark/arc/spark

Gotchya thanks.

 

[terry32506]

Re: Problems with a 6 hp Johnson

Welcome to Iboats,

Your condition seems like a exhaust leak problem. Exhaust leaks are common for the the Evinrude/Johnson 9.5hp from 1964 to 1973. But as you clearly state that you have 1977 6hp.

Did you have to remove the power head from the exhausting assembly? If you did, did you replace the exhausting gasket between the power head and exhausting assembly? Because if the exhaust housing gasket is torn or leaking that could be your source of built up exhaust and the need to remove the cowl in order to for motor to get adequate amount of oxygen and not re-breath its own exhaust. Look at the link.

http://www.boats.net/parts/search/BRP/JOHNSON/1977/6R77M 1977/EXHAUST HOUSING/parts.html

parts 1 and 79

Another possible area could be a leaking gasket from the exhaust outer or inner covers located on the tiller side of the motor. Again causing the same situation as described above. Look at the link.

http://www.boats.net/parts/search/BRP/JOHNSON/1977/6R77M 1977/CYLINDER & CRANKCASE/parts.html

parts 27, 28,and 29


I'm speculating here, but I'm sure one the forum's GURU's will chime in a give a experienced perspective.

Good luck, I hope you are able to figure it out. Nice little motors, I have a 1967 model.

cajuncook1

No all I done was checked them to make sure they werent loosened up. Could be a crack in the gasket is what im thinking. Not going to tare it all down might just have to go hatless for this year. lol

 

[cajuncook1]

Re: Problems with a 6 hp Johnson

Not that hard to do, the 6hp motors are pretty simple and easy to work on. Get a service manual for your motor and your set.

Good luck to ya and hats off!!

cajuncook1

 

[terry32506]

Re: Problems with a 6 hp Johnson

Not that hard to do, the 6hp motors are pretty simple and easy to work on. Get a service manual for your motor and your set.

Good luck to ya and hats off!!

cajuncook1

Oh yes im sure I could but running out of time , im a pram boat builder and not enough time to build boats & rip down motors but something I could definitely get into over the winter.

 

[BigB9000]

Re: Problems with a 6 hp Johnson

you could be having this problem

 

[terry32506]

Re: Problems with a 6 hp Johnson

you could be having this problem

Ah nice video demonstration. I will try that and see. The plug wires are pretty old..With a little luck maybe thats the culprit. Forgot to mention my motor is painted white, could the spark still ark through the paint?

 

[BigB9000]

Re: Problems with a 6 hp Johnson

Its going through the paint on mine.
and the plug wire!

 

[cajuncook1]

Re: Problems with a 6 hp Johnson

Ah nice video demonstration. I will try that and see. The plug wires are pretty old..With a little luck maybe thats the culprit. Forgot to mention my motor is painted white, could the spark still ark through the paint?

Viewed the video and it was interesting, but it would continue to arch and discharge even though the cowl was off. My assumption still lies with the exhaust leak.

Hope you get this sorted out and your able to do some fishing!!!

cajuncook1

 

[terry32506]

Re: Problems with a 6 hp Johnson

Viewed the video and it was interesting, but it would continue to arch and discharge even though the cowl was off. My assumption still lies with the exhaust leak.

Hope you get this sorted out and your able to do some fishing!!!

cajuncook1[/QUOTE

Oh I will be fishin alright one way or another lol...My 14 year old son will probably be using the motor more while I row around in my little fly fishing pram that I build and fish and fish and maybe sell a couple in the process