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Onan Dd Carb Gasket Question


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#1 coldone OFFLINE  

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Posted August 09, 2013 - 07:39 PM

The two big gaskets have a slight difference in the cut outs. One has a banana shaped hole the other has a round hole. Why the difference and how do you know which one to use? The reason I ask is that I have  DD carb that you can fully close both the idle and main jet and it still gets gas. I cant figure out why it is doing this and the only thing I can question at this point is the difference in the gasket cut outs.

 

The holes in question are at the 11oclock position around  the big center hole.

 

 

mEi-YSjPlqHKpoUnTIH6sug.jpg

 



#2 olcowhand OFFLINE  

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Posted August 09, 2013 - 08:45 PM

Been quite some time since being into a DD carb, but I do know they do strange things.  Without having a carb in front of me to look at, I don't know why the different cutouts in those gaskets. I "think" all mine had the smaller hole.


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#3 superaben OFFLINE  

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Posted August 09, 2013 - 09:16 PM

I don't know much about Onan, but I do know that needle seats will wear and not seal.  Also, the spring for pressure can prevent the screw from tightening all the way.  In other carburetors, there are vent holes and other secondary jets that can get fuel to the engine, albeit not enough to run.

 

Ben W.


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#4 coldone OFFLINE  

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Posted August 12, 2013 - 08:54 PM

Well, I still aint sure what the difference between the two gaskets do but I can tell you that I had to make my round hole into a banana shape.

 

I had been through this card before, with a kit. The gasket that came out of it had a round hole, so a round hole went back into it. That was probably a year ago. I never could get it to run right. I even went and decked the two carb halves to make sure they were flat. Still couldnt get it set right. I then made a thicker gasket, with a round hole. Still no joy with that setup either. The D200 came into my world and I stopped working on the D160 that this carb was on. The D200 busted an axle bearing the other week, so I decided it would be quicker to get the 160 up and running so I could mow. I had purchased a Nikki card to use on the 160 so I made an adapter plate for it but before I switched over to the nikki I decided to try the DD one more time. Thats when I started this thread.  I figured I had nothing to loose so I expanded the hole into the banana shape and reinstalled everything. I set the adjustment screws and after a minute of cranking she fired up. A few adjustments and I was off and running. I changed out the fuel line and filter and had to make one small adjustment on the main jet while I was actually mowing. She ran great the  and I mowed my yard with it, about and hour. 






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