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kawimaniac2145

engine surging

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lynnmor
12 hours ago, kawimaniac2145 said:

it still surges at high rpm and how do i adjust it.

 

Was the welch plug missing?  Did you clean all the small holes behind it?  There is no adjustment for high speed mixture, only the idle mixture if it has a idle mixture screw.  To adjust the idle, do this:

 

1. Back off the idle adjustment screw located near the throttle cable.

2. Adjust the throttle stop screw for 1000 RPM.

3. Adjust idle mixture screw for the highest speed and best idle.

4. Readjust the throttle stop screw to 1000 RPM if necessary

5. Readjust the mixture if necessary.

6. Repeat steps 4 & 5 if necessary.

7. Adjust the idle adjustment screw near the throttle cable to 1200 to 1400 RPM.

8. Insure that the throttle cable pushes the lever to the stop, the speed should be 3600 RPM, bend the stop if needed.

 

If you still have problems, check for damage, adjust the float level and clean the carburetor.

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kawimaniac2145

there is no damage. and the float is level with the base of the carb. mine has a screw below the carb. is that the mixture screw.

and if it is. how do i get to it. the muffler is in the way?

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WheelHorse520H
21 hours ago, kawimaniac2145 said:

there is no damage. and the float is level with the base of the carb. mine has a screw below the carb. is that the mixture screw.

and if it is. how do i get to it. the muffler is in the way?

I believe you have to take the muffler off. Not sure if that is the screw you need or not but I would take the muffler off.

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lynnmor
23 hours ago, kawimaniac2145 said:

there is no damage. and the float is level with the base of the carb. mine has a screw below the carb. is that the mixture screw.

and if it is. how do i get to it. the muffler is in the way?

 

The float level adjustment is on page 7-3 of the Onan Service Manual.

 

The idle mixture screw can be adjusted with a long skinny screwdriver at a bit of an angle, there is no need to remove anything.

 

Example  of a screwdriver that is much longer than you really need, but will work fine.  A flashlight helps to locate the screw.

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kawimaniac2145

do all of you think it can be that the intake manifold gasket material could be allowing air to get sucked in

 

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lynnmor
2 hours ago, kawimaniac2145 said:

do all of you think it can be that the intake manifold gasket material could be allowing air to get sucked in

 


Did you replace them and use genuine Onan gaskets?  Is so, did you use a torque wrench?
 

Usually a leak there would cause more problems at idle than high speed.

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kawimaniac2145
19 hours ago, lynnmor said:


Did you replace them and use genuine Onan gaskets?  Is so, did you use a torque wrench?
 

Usually a leak there would cause more problems at idle than high speed.

i was talking on the intake manifold itself.

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lynnmor
4 hours ago, kawimaniac2145 said:

i was talking on the intake manifold itself.

There are three gaskets, two where it attaches to the engine block and one where the carburetor attaches.

 

The intake manifold is two pieces with a sealant between the two.  The test by spraying carb cleaner was discussed earlier.

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