Notices
Engine Conversions Discuss all aspects of engine conversions in this forum

Plumbing a Zama carb with primer bulb

Old 07-22-2011, 03:58 PM
  #1  
ckangaroo70
Thread Starter
My Feedback: (51)
 
ckangaroo70's Avatar
 
Join Date: Oct 2003
Location: London Mills, IL
Posts: 2,355
Received 2 Likes on 2 Posts
Default Plumbing a Zama carb with primer bulb

Hello

I recently aquired another converted Ryobi engine and this one has the Zama carb with a primer bulb on the carb. I am not real familiar with this type of setup and neither of my previous 2 ryobi engines had a primer bulb on the carb. This particular carb has two brass tubes on top of the carb. An inlet and outlet I presume, but I am not quite sure how this is supposed to be plumbed? Do I have to use a three line tank setup? Which brass tube on the carb is the actual fuel inlet. You push the primer bulb and one will suck a little and I suppose the other one is probably blowing. This should all be real simple, but I am having trouble wrapping my mind around how exactly this needs to be plumbed? Any help from some of the wise engines conversion guru's here would be appreciated.
Old 07-22-2011, 04:05 PM
  #2  
ckangaroo70
Thread Starter
My Feedback: (51)
 
ckangaroo70's Avatar
 
Join Date: Oct 2003
Location: London Mills, IL
Posts: 2,355
Received 2 Likes on 2 Posts
Default RE: Plumbing a Zama carb with primer bulb

I have the engine all mounted to the plane and ready to roll...just need to figure out this tank plumbing. This is my second Sig Rascal 110 with a Ryobi 31.My first one was the red and white version and it was a fantastic flyer with the Ryobi on the nose. I hope this one runs just as well.
Attached Thumbnails Click image for larger version

Name:	Tr49380.jpg
Views:	45
Size:	222.8 KB
ID:	1638660  
Old 07-22-2011, 04:12 PM
  #3  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,576
Received 9 Likes on 9 Posts
Default RE: Plumbing a Zama carb with primer bulb

The one on the pump side of the carb should be the fuel inlet.

The other one should come from the regulator side of the carb.

If you do not use the bulb, you must plug the one that would go to the bulb or it will suck air.

If you are hooking the bulb up, the outlet from the bulb just has to go into the tank. Where and how far is not important.

The fuel inlet must go to a clunk in the tank. You can put a tee in this line with a fuel dot or plug when not fueling the plane. It will not flood the carb.

The tank must have a vent line to to atmosphere. It must come from the top of the tank and exit at a point lower than the tank.


Old 07-22-2011, 04:39 PM
  #4  
ckangaroo70
Thread Starter
My Feedback: (51)
 
ckangaroo70's Avatar
 
Join Date: Oct 2003
Location: London Mills, IL
Posts: 2,355
Received 2 Likes on 2 Posts
Default RE: Plumbing a Zama carb with primer bulb

Ok thanks. That sounds like the way I have mine hooked up, but both my inlet and outlet tube are one the same side of the carb and within 1/4" of each other which is unlike the zama carb I had on my other ryobi which had a tube on different sides of the carb. I currently have it plumbed for three lines. A main clunk line, a vent line and one return tube that acts as a return fuel line from the primer bulb. I was just curious if I had things right because I went to start it yesterday for the first time and it didn't even fire after I primed the bulb. It was a bazillion degrees outside when I was messing with....so I gave up rather quickly and didn't even take time to pull the plug to see if it was wet. So I thought I had better check from you coversion engine guru's to see if I have my plumbing right before I mess with it again.
Old 07-22-2011, 04:55 PM
  #5  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,576
Received 9 Likes on 9 Posts
Default RE: Plumbing a Zama carb with primer bulb

The fuel inlet is closer to the engine than the one for the purge bulb.
Old 07-22-2011, 05:36 PM
  #6  
rangerfredbob
Senior Member
My Feedback: (13)
 
Join Date: Jul 2005
Location: Salem, OR
Posts: 1,686
Likes: 0
Received 0 Likes on 0 Posts
Default RE: Plumbing a Zama carb with primer bulb


ORIGINAL: w8ye

The fuel inlet must go to a clunk in the tank. You can put a tee in this line with a fuel dot or plug when not fueling the plane. It will not flood the carb.
w8ye, are you meaning to put the tee in the return line? that's a better idea in my mind, and what I did with my carb with a primer bulb on it...
Old 07-22-2011, 05:38 PM
  #7  
ckangaroo70
Thread Starter
My Feedback: (51)
 
ckangaroo70's Avatar
 
Join Date: Oct 2003
Location: London Mills, IL
Posts: 2,355
Received 2 Likes on 2 Posts
Default RE: Plumbing a Zama carb with primer bulb

Thanks for the great info. One more question.....I have the return line going from the return line on the carb to a brass line that enters the tank, but does not have a clunk line like the fuel inlet line does. My question is....what happens when the fuel in the tank drops below half and the brass inlet tube is no longer in fuel? Does it then allow air back into the system? On my previous Ryobi/Sig Rascal setup I used a two line tank. I had a fuel line and a vent line. The prime line I had just a short piece of tubing that I enjected fuel into using a syringe and then I would just cap that line with a fuel dot after I shot the charge of gas into the line. The way I have this one setup...it would almost be like leaving that line uncapped once the fuel dropped below the brass return tube in the tank. In my mind it almost makes me think that line should maybe have a line and clunk on it as well so it will always be in fuel. What I am I not getting? Thanks
Old 07-22-2011, 05:41 PM
  #8  
w8ye
My Feedback: (16)
 
w8ye's Avatar
 
Join Date: Dec 2001
Location: Shelby, OH
Posts: 37,576
Received 9 Likes on 9 Posts
Default RE: Plumbing a Zama carb with primer bulb

If you are using the primer bulb it doesn't matter.

There is a check valve in the primer bulb assembly and there is the regulator needle and seat in the metering side of the carb, so in the supply line you are not going to flood the engine with either way
Old 07-22-2011, 05:42 PM
  #9  
ckangaroo70
Thread Starter
My Feedback: (51)
 
ckangaroo70's Avatar
 
Join Date: Oct 2003
Location: London Mills, IL
Posts: 2,355
Received 2 Likes on 2 Posts
Default RE: Plumbing a Zama carb with primer bulb

rangerfred

I don't have a tee in my main line, but I do have one of those new black plastic Dubro fuelers inline. I also have one on a Yak 54 with a Zenoah G23 and I like that new fueler much better then those aluminun fuelers that the seals always dry up on and leak air.
Old 07-22-2011, 05:48 PM
  #10  
ckangaroo70
Thread Starter
My Feedback: (51)
 
ckangaroo70's Avatar
 
Join Date: Oct 2003
Location: London Mills, IL
Posts: 2,355
Received 2 Likes on 2 Posts
Default RE: Plumbing a Zama carb with primer bulb

[youtube]http://www.youtube.com/watch?v=ftASjepWrz4[/youtube]

If I can get this new Blue and White Rascal 110 and Ryobi to run as good as my last Red and White one...I will be real pleased.Thanks for the great info and help guys.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.