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Chrisitine Green
 
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Default Johnson 90 down to 3 cyls under 2000 RPM

Hello All,



I am hoping someone can help with a problem I am having with my 1995 60deg V
Johnson 90 HP outboard. The motor is dropping back to three cylinders when
running under 2000 RPM. I have pulled the plug leads to identify the
cylinder and it appears to be the top right one (looking from the back of
the motor).



I have done the following:



Compression check: around 910 kPa on all cylinders.

Replaced plugs: No Change

Measured lead resistance: around 600 ohms per lead.

Adjusted air bleed screw on affected cylinder: No Change



When I pulled the leads to identify the missing pot, I had spark jumping
from the plug lead to the plug so I suspect it is not a spark problem. This
leads me to think it maybe a blocked carby jet but I have never pulled them
off so not sure how big a job this is. Any suggestions as to what the
problem might be or the difficulty of pulling of the carby an cleaning the
jets would be greatly appreciated ..







Daryl


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JR North
 
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Default Johnson 90 down to 3 cyls under 2000 RPM

Prolly a clogged slow jet on the affected cyl/carb. Try hand choking the
carb with the engine revved, if that's possible. Sometimes works wonders
and avoids a tear-down.
JR

Chrisitine Green wrote:

Hello All,



I am hoping someone can help with a problem I am having with my 1995 60deg V
Johnson 90 HP outboard. The motor is dropping back to three cylinders when
running under 2000 RPM. I have pulled the plug leads to identify the
cylinder and it appears to be the top right one (looking from the back of
the motor).



I have done the following:



Compression check: around 910 kPa on all cylinders.

Replaced plugs: No Change

Measured lead resistance: around 600 ohms per lead.

Adjusted air bleed screw on affected cylinder: No Change



When I pulled the leads to identify the missing pot, I had spark jumping
from the plug lead to the plug so I suspect it is not a spark problem. This
leads me to think it maybe a blocked carby jet but I have never pulled them
off so not sure how big a job this is. Any suggestions as to what the
problem might be or the difficulty of pulling of the carby an cleaning the
jets would be greatly appreciated ..







Daryl




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Home Page: http://www.seanet.com/~jasonrnorth
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posted to rec.boats
Chrisitine Green
 
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Default Johnson 90 down to 3 cyls under 2000 RPM

Thanks JR

The hand trick didnt work but the carby was easy to get off. It was a
blocked jet and now running like a dream.




"JR North" wrote in message
...
Prolly a clogged slow jet on the affected cyl/carb. Try hand choking the
carb with the engine revved, if that's possible. Sometimes works wonders
and avoids a tear-down.
JR

Chrisitine Green wrote:

Hello All,



I am hoping someone can help with a problem I am having with my 1995
60deg V Johnson 90 HP outboard. The motor is dropping back to three
cylinders when running under 2000 RPM. I have pulled the plug leads to
identify the cylinder and it appears to be the top right one (looking
from the back of the motor).



I have done the following:



Compression check: around 910 kPa on all cylinders.

Replaced plugs: No Change

Measured lead resistance: around 600 ohms per lead.

Adjusted air bleed screw on affected cylinder: No Change



When I pulled the leads to identify the missing pot, I had spark jumping
from the plug lead to the plug so I suspect it is not a spark problem.
This leads me to think it maybe a blocked carby jet but I have never
pulled them off so not sure how big a job this is. Any suggestions as to
what the problem might be or the difficulty of pulling of the carby an
cleaning the jets would be greatly appreciated ..







Daryl



--
--------------------------------------------------------------
Home Page: http://www.seanet.com/~jasonrnorth



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