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Bob V

O&R Tiny Tiger Generator Carburetor

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Posted (edited)

I am a newbie here and also new to the O&R Tiny Tiger generators. I had to remove the carburetor to unblock the fuel inlet and to install a new kit. While the carb was off and apart,  what looks like a small locator pin fell out of it and I have spend hours trying to figure where it goes. It is a black solid straight pin about 1/4" long and about 3/32" wide. It looks like a small black grain of rice. Does anyone have a clue where this pin goes?  Thanks in advance. 

 

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Edited by Bob V

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Hi again to all of you experienced O&R engineers. I have a question and I know one or more of you has the answer. I have a Tiny Tiger 300 generator. When I push the prime button on the top of the carburetor, I can see the fuel flowing back to the tank instead of towards the carburetor. So, I have not been using the primer. When the unit is cold, I move the lever to full choke and within three to four pulls, it fires. Then I move the lever to half choke and then to no choke and it runs fine. So it does run fine without using the primer, but I would like the primer to work as well. So my question is why is the primer not working like it is suppose to. Seems to me that there is a check valve somewhere in that carburetor that is not functioning ? As I mentioned, when I push the primer button, it is pushing the fuel from the carburetor into the tank. Any advice will be greatly appreciated.  Thanks, Bob

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The little steel ball bearing in the carb is not sealing. You can see the bearing in the carb pic above. That ball bearing sitting in the hole is the check valve. If fuel is pushing back past the ball, you can see it travel towards the tank. If the ball is sealing well, the fuel will travel through the carb to the engine.

Getting that ball to seal better will help with performance of the engine.

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Thank you so much. Does any one on here have those balls for sale? My thought is that if I am going to remove it to inspect it, it would be wise to have a new one on hand in case the old one is worn or rusted.  Thanks...

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There were 2 different sizes but I "believe" yours would be the smaller of the 2 . They are 1/16 and 3/32 ball bearings. They can be found at old school type hardware stores with all the little parts in the drawers.

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On 8/29/2022 at 7:05 PM, Bob V said:

in case the old one is worn or rusted.

Or, just in case it disappears like a sock from the dryer! No one knows how it happens but we all know it does happen. LoL

 

Once it's all back together use a piece of fuel line connected to the inlet and try to blow in it. It should only allow air to pass when the primer button is pushed. If it's allowing air to pass otherwise it's not sealing and therefore not check valving.

Some carbs allow the cover to push down on the little arm ever so slightly too. I typically don't use a paper gasket along with the diaphragm but I do add one when this condition occurs. It's an easy solve compared to trying to bend that little arm.

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I have been restoring vintage chainsaws for customers around the country for over twenty years and I know all the Tillotson, Walbro and Zama carbs like the back of my hand, but this little O&R carb amazes me. There is a lot going on in a very small package. I will let you know the final results. Thanks again for your help. 

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Ball....what ball...??  I opened up the carburetor up this morning and to my surprise, there is not ball inside. It has a rubber pad attached to the lever arm (see pictures). From there it just got worse. I went to reinstall the lever arm and spring and the black rubber pad fell off the arm. It has a tab that goes through the arm and that tab broke off. So now I am up the creek without a paddle. Is it possible that someone would have one of those arms or do I need to find another carburetor? 

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Those rubber pad arms are the newer type and difficult to find as there were not near as many produced. They tried to band aid the carb again with that fix instead of the ball.

You can try sending a PM to @Mike in NC as he recently posted a big parts find and may have something in there for you. He never mentioned if he was going to sell anything or not but worth a try.

A product called Seal-All will stand up to the fuel or Yamabond sealer to try and glue it .

Since I'm always working on bush fixes for unobtainable things, I was looking at the Kohler carb float valves. They have a rubber tip on them which is about the same size. Never tried it yet but if it can be cut off clean and flat, then poke the point (may need to be sanded or cut a little) through the arm hole, Use a solder iron or something to melt the rubber to lock it in the hole.

Small RC check valve or valves in the fuel line before the carb?

Changing the diaphragm body to a ball type. It will bolt right on

 

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Posted (edited)

Thank you for your reply. Do you have or do you know of anyone that has ball type diaphragm body that they would be willing to sell?  

Edited by Bob V

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Guys, I really need your help with this TT300 carburetor. This is the first O & R carburetor that I have ever worked on so I have nothing to compare it to. When I bought this TT300, it did run, but the primer was not working. The only way to start it was to put it on full choke and pull the recoil until if fired. When I previously inquired about the primer not pumping some of you suggested that the ball was not sealing. I pulled the carburetor apart and found that it does not have a ball top, but rather a lever arm with the rubber pad. Here is where it gets interesting. When I had the carb apart I noticed that the spring was much more forward than it should have been and it was missing the diaphragm roller (#10 in the diagram below). However, it did run and ran well with the exception of the primer not working. Then the rubber pad fell off of the arm. Wallfish was kind enough to send me a replacement arm with the pad and a diaphragm roller. I installed the new arm and then installed the spring with the diaphragm roller positioned like it should be under the open end of the spring. I also installed all new gaskets in the carb. Again, it would not prime. I put it on full choke and pulled the starter about twenty times until it fired. Once it fired, it ran, but seemed to be running lean. Before I disassembled the carb, I had the needle out one turn from closed and it was running at 6,200 rpms - no load and responded to adjustments to the needle. Now, with the new arm, diaphragm roller and new gaskets, I have the needle out two turns from closed and it is running at 6,800 rpms - no load. If I turn the needle in, rpms will climb, but there is no decrease once the needle is more than two turns out. I have taken the carb apart several times and cannot fine anything unusual, but again, this is my first O & R engine and the problem may be looking me in the face and I cannot see it. When there is gas in the fuel line and I try to prime it, I can see the gas in the gas line pushing back to the tank - opposite of what is suppose to happen. I thought that maybe the new arm was not sealing, but I while I had it apart, I put a piece of hose on the inlet nipple and sucked and blew while the arm was in the up position and it was totally sealed. When I pushed down slightly on the arm, air flowed freely through the nipple. Another thing that I just noticed is that this carburetor did not come with a diaphragm disc (#14 in the diagram below). I have been told that some carburetors came with it and some did not. It seems that it would be needed when priming to push the diaphragm back up? Any help that any of you can give me will greatly appreciated...!! 
 
 

 

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Edited by Bob V
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Ah man, wish I knew it was missing the metal diaphragm disc. The arm can wear the diaphragm but it can work and run without it.

Make sure the thin plastic check valve (#6) is on top of the gasket. It seals the little hole on the diaphragm body

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Hi John - Thank you for taking time to help. I know that your spare time is almost non-existent. I wish I knew that it was suppose to have a diaphragm disc. I did not realize it until I saw the diaphragm. It made sense to me that it needed the disc because when you push the primer button down, there is nothing to pick it back up other then the arm and that would not have much effect against the soft diaphragm. All the chainsaw carbs that I rebuild have an attached disc. It appears that the former owner of this TT300 lost several parts in the carb. The diaphragm roller, that you supplied,  and the diaphragm disc were missing.  I sent you better picture of the carb internals in another -e-mail to your yahoo address. I do have the check valve installed properly although the pictures make it look otherwise. If you have a diaphragm disc, I would be more that happy to buy it from you or trade you for some Homelite engine parts.  I just sent you better pictures of the carb internals. If you see anything else that is missing or not correct, please let me know.

 

Thanks again ~ Bob

Edited by Bob V

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SUCCESS...!!

 

Another TT300 comes back to life. Wallfish, without you this would have been just another one of those non-running display models. I cannot thank you enough...:tthankyou:

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Edited by Bob V

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