99 Johnson 200hp crab air fuel mixture screw

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I’m having a hard time getting low end power from my
99 Johnson 200hp. It’s carbureted and I only have one adjustment witch is air fuel mixture.

i can get it to run at 8 turns out but it seams to back fire or sneeze. It’s a 200hp on a 18ft bay boat. I can’t get it to plane with more than 2people on it. I have a 17inch pitch prop on it and it feels good in the high end but stumble out the hole.

I welcome any suggestions and thanks for taking a shot at this

 

[Faztbullet]

Get a FACTORY manual and adjust them correctly..You cannot adjust on muff..has to be in water,in gear to adjust

 

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I do have the manual and I do have it it the water.

 

[racerone]

Model # of the motor ?----It has six carburetors and a slow speed mixture adjustment on each carburetor.-----Other than carburetor adjustments what trouble shooting has been done so far ??

 

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J200pxeen

timing was set in water in Forward. 4degrees
i pulled the fly wheel checked the magnets
changed the optical sensor
checked stator
replaced powerpack
checked coils
new plugs and wires
new thermostats and gaskets
i have cleaned the carbs twice to be sure
new carb to throttle plate o rings

 

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Also did a link and sink
and changed to premix by plugging the oil input and unplugging the sensor

 

[racerone]

I do not believe that motor has an optical sensor.----Post the results of a compression test.-----What pitch is the prop that is on this motor ?----Have you looked into possible issues with crankcase compression .----Possible issue with reed valves ?

 

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Timer base not optical sensor sry
100 1-5
105 cyl 6

 

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How could I Chec
k the crank case pressure?

 

[oldboat1]

just a poor country boy, but I would measure spark with an adjustable tester (not the inline type), and check/record compression for each cylinder. Might post results here for feedback.

Sounds like the idle air mix is pretty rich, maybe overcorrecting for another issue.

 

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13 3/4 in 17pitch
just got a chance to run it and it looks like after 15 mins of running it runs better. I just replaced the gasket prong carb to throttle plates and now I’m at 4.5 turns and seems to be running a lot better.

now if I pump the bulb hard and many times it will run better and have more power. Looks like a fuel pump issue.

the local parts shop has sections of the vro for sale. Any recommendations on what to look for?

 

[oldboat1]

4 1/2 turns sounds much better. Problem may have been rich running.

On the fuel pump, see if the parts shop has a rebuild kit (diaphragm replacement). Ask for advice on replacing the VRO as well with a standard pump or pumps -- not a criticism of the VRO system, but may be a route to go if premixing is not a problem for you (50:1).

 

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Thanks for the help!
I’d like to close this thread because this issue I’m dealing with now is not related to the tittle. Thanks guys I appreciate everything

 

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Just in case anybody can be if it from this I had bad carb to throttle plate gaskets and my fuel pump got a hole in the diaphragm. Witch made the motor no run at idle and every time I did a carb adjustment it seemed to get back but after a few minutes it would run lean and miss.

things that helped were
new gaskets
new pulse limiter
new fuel side diaphragm on vro
the people on this site

this forum is a real resource and I thank everyone who participates