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

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




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

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