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1974 SS16 Onan Carb questions


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#16 Captain OFFLINE  

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Posted November 06, 2015 - 10:35 PM

I agree. Try and get it running first. Then determine, what, if anything, is wrong. You may find that all is ok, saving you a bunch of time and money. Plus, if you start tearing stuff apart before you have it running, if it doesn't run after you fool with it, then you won't know if it was a previous problem or something you inadvertently created.

At the end of the day, have fun and good luck.

So there are two reasons I want to rebuild the carb before I start it... 1) Its been sitting for at least 3 years and I figured the gaskets and probably the fuel pump diaphragm are shot. 2) The first thing I did when I started checking out the motor was open up the air filter. I notices a small metal shaving about the size of a fingernail clipping sitting at the bottom of the filter next to the carb hole. When I tried to get it out I knocked it in the hole :( I know... DUMB MOVE. I might try and see if I can stick a magnet down there and get it out or suck it out with my shop vac with a shirt over the end of the vac so I will know if I got it because it will be stuck to the shirt.



#17 Captain OFFLINE  

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Posted November 06, 2015 - 10:43 PM

No, don't screw them in tight.  Before removing them, screw them in until they just bottom out and count the number of turns needed.  Be very careful because if you screw them in too tight they can be damaged.  After cleaning and during re-assembly, you will need to adjust each jet so they are screwed out the same number of turns that you screwed them in before removal.  This should get your carb jet settings close and then you can do some fine tuning while the engine is running.  Hope this makes sense.

 

Just want to check that I understand this...

 

So before I take the jets out, I screw them all the way in until they "bottom out" (do you mean snug but not too tight?). Then I screw them out and count the rotations. Then, when I screw them back in, I screw them the same number of rotations that I screwed them out.

 

Why tighten them before taking them out? Shouldn't I just screw them out from where they are now, count the rotations, and screw them back to that exact spot? Or should you always start with them "bottomed out"?

 

As for the "fine tuning" that's all in the manual right? I saw a section on tuning in there. I have the original manual from the tractor and I printed the manual for the motor.



#18 Captain OFFLINE  

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Posted November 06, 2015 - 10:47 PM

I have the kit for the carb in stock if you need it http://bobsgardentra...570?search=carb  As for the float is there a reason you need to replace if not I would leave it.

 

Thanks for the link! The reason I planned on replacing the float is just from people suggesting that the original float is probably no good at this point. I figured I might as well do it while I have the carb apart. I guess there is always a chance I open it up and it already has a brass float. I don't know what work has been done to this tractor other than a paint job. It was REALLY well cared for. My friends parents bought it new and have kept in garaged since 1974. It barely has any rust on it!



#19 motobreeder OFFLINE  

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Posted November 07, 2015 - 08:12 AM

You can turn in (gently) the mixture screws to count the number of turns.  The initial setup of a carburetor is based on the number of turns registered from all the way in.

 

Each carburetor/engine model has a default number of turns as a starting point for tuning.

 

i wouldn't worry about the current setting - it may not be optimal or may change if you clean the carburetor.



#20 wahoowad OFFLINE  

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Posted November 07, 2015 - 08:31 AM

Just want to check that I understand this...

 

So before I take the jets out, I screw them all the way in until they "bottom out" (do you mean snug but not too tight?). Then I screw them out and count the rotations. Then, when I screw them back in, I screw them the same number of rotations that I screwed them out.

 

 

  1. Screw them in until they stop and count rotations (don't force them)
  2. Screw them out and clean/rebuild
  3. Screw them all the way in
  4. Back them out the same # of turns from step 1


#21 Jazz ONLINE  

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Posted November 07, 2015 - 02:39 PM

This note was in my owners manual when I bought my SS16 last year.

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#22 bbuckler OFFLINE  

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Posted November 07, 2015 - 02:45 PM

This note was in my owners manual when I bought my SS16 last year.

Some small engine shops charge 10x what it should cost.



#23 Bolens 1000 OFFLINE  

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Posted November 07, 2015 - 04:09 PM

This note was in my owners manual when I bought my SS16 last year.

 

That was likely if you went directly through Onan...... We buy them directly from the carb manufacture and I sell them for $ 70.00

The kits are still USA made too!



#24 toppop52 ONLINE  

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Posted November 07, 2015 - 07:20 PM

Just because it's a brass float doesn't mean it's any good though. I just put a new one in mine because the old one was full of gas.

#25 JiminRI OFFLINE  

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Posted November 17, 2015 - 02:13 PM

I also have an SS-16 and have worked on the carb. It is a Marvel Schebler Model DD. Manuals are available on line (you can PM me if you can't find one). I also recommend running it before you disassemble. Mine was stored for ten years before I took it out of storage a couple of years ago. It did run fairly well so I did not completely disassemble the carb. I removed the top half to clean it up and replace the fiber float with a brass float. If you have the fiber float, replace it!

Regarding the jets. I removed both jets and replaced the high speed jet due to wear (it should have a tip like a sharpened pencil and a good O-ring). When replacing the jets I screw them all the way in gently to avoid damage. Then I loosen them one and one half to two turns to allow the engine to start, then fine tune once the engine warms up. There are lots of good videos on Youtube.

Good luck,

JiminRI






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