I need help
I am converting a 25cc 2 barrell and I can't get it to run right. Before I tore it down it ran perfect now that I have it mounted in the plane it won't stay running. It will start but acts like it is starving for fuel. I had it running yesterday for about 1 minute and then it died. since then it will only spit and spudder but won't stay running. I checked and rechecked all of the fuel lines to make sure it wasn't sucking air, I am confident that the fuel lines are good. Do I have to run the primer bulb with this carb? I am at a loss here. I'm about ready to throw this motor in the garbage. please help.

The first question is if you rotated the carb for easier access with the throttle hookup or adjustment needle access. If so, your pulse hole that operates the fuel pump in the carburetor might not be lining up. Some carb/manifold combos you can rotate the carb 180 degrees and the pulse hole still gets a pulse, and others you cannot rotate without further modifications.

Next is to start from scratch and review your fuel system. The pump in the carb is very sensitive to air leaks, and will not pump fuel if there is an air leak in your fuel system. You do not have to use a primer bulb, but you DO have to be sure the fuel line is connected to the proper fuel inlet port. The inlet port is usually the one closest to the cast aluminum cover with one big screw in it on the carb. The other fuel port must be closed off.

You can also try richening the mixture screws a bit, because when you take off the air cleaner, and/or provide a more free breathing exhaust, the engine will lean out from it's original setting. You have to open the needles a bit to compensate. I would say open them about 1/2 to 3/4 turn and try again.

Lastly, if the engine sat around for a while before you mounted it on a plane and tried to fire it up, the diaphragms in the carb may have gone bad. I have had them go bad in as little as a month with some fuels. It is usually the diaphragm under the cover with the four screws, (regulator) that goes bad. That diaphragm has to be very supple. If it is the least bit stiff, replace it.

Let us know how it goes,
AV8TOR

Check this old thread (Post #8):

http://www.rcuniverse.com/forum/m_3177293/tm.htm

thank you for your reply
I just got it started and is is running fine, I still am baffled as to what is going on and why it is so hard to start. The 2bbl carb doesn't have any visible screw adjustments that I can see. In order for me to get it to start I did hook up the primer bulb pushed it about 6 or 7 times choked it gave it a couple clicks above idle and spun it over with a chicken stick. it popped but still wouldn't start. Next I squirted a little fuel into the carb then started the process all over again. It fired that time. I have ran it twice now and even after priming it with the bulb and choking it. it wouldn't start without squirting a little fuel directly into the carb. That has me baffled. I can visually see fuel being pumped into the lines when I pump the bulb. I have very little experience with this 2 bbl carb so it all new to me. Once it gets going it seems to run fine, Doesn't like to idle down well without dieing but throddles up well. I have burned 2 tanks now of fuel so we will see. Any other suggestions would be appreciated.
If anyone is curious I am building a senior telemaster with the toro 25cc. As far as mods go I doubled the size of the rudder, replaced all of the factory junk hindges with good ones, reglued as much of the plane as possible. The factory glue seems like a hot glue of sorts. I reinforced the firewall seeing that I am putting a gasser on it. I got rid of the rubber band idea and built a better mounting system for the 2 piece wing. It's ready to go other then being confident in the engine. We'll see how it goes. Oh yea still need to build the wing struts, no biggy.

thanks
I've actually been reading that thread for awhile now. that's what got me interested in the toro in the first place. Couldn't find anywhere in there about problems like I am having.

It seems to me that Post #8 of that thread explains the difficulty to achieve proper iddle without two adjusting screws for RC use, and the reasons.

For some time I was working repairing and servicing weedeaters and dealing with these little engines.
Many times, they needed a spray shot of carburator cleaner or WD-40 to start.

Yours is an interesting project, please don't throw this engine in the garbage!!
Regards!

Ok I am on my third tank of gass now. You are right I shut down the engine just long enough to refuel and went to start it again and nothing. It wouldn't start without squirting a little fuel into the carb even though the engine was still warm. Right now I am seeing how long it will run on a tank of fuel at just over 1/4 throddle. 16oz tank.
a few other mods I forgot to mention is I did a pull-pull on the rudder, dual servos on the elevator surfaces, I'm in the middle of building a candy drop box. still trying to figure out how to open and close the doors with a servo. I left the entire center fusalage empty for the drop box. I did this for a couple of reasons. drop box and eventually I want to build a camera system with pan and tilt. I am trying to make it easy removal and install of the different components. also just have a cover plate when I am just buzzing around the field here at home.
one thing I have learned is the covering that is on the arf is junk if you get a little mixed fuel on it it bubbles. Gonna have to recover it before long. I think I will fly it a few times to see how it does. Winter is coming up that would be a good time to recover the whole thing with ultra cote. Although I am planning on building some fiberglass skis for winter.. We will see..

alright I just shut it down. It ran for 50 minutes at about 1/4 throddle and still has 1/4 tank of fuel left. that's a 16oz tank not bad compared to my 50cc katana with a 24oz tank. I can only go for about 20 minutes. granted I am flying way over 1/4 throddle 95% of the time. I give this motor another chance.. Maybe now that I have figured out how to start this engine it will get easyer.

I have a Toro and love it.

I think you need another Carb.

Do you have the side ports blocked off?

Ralph,
No I am running stock, The engine you have pictured is different then the one I have. Mine is the 2 barrell carb, It seems to run fine once you get it going, it's just a pain to get started.

What kind of carb is it?

This is the 2 barrel version.
With everything cut off and glass bead blasted.
The nipples where the hoses go have been blocked off with the plates.

I had this on a 60 size Tiger Moth so I had to loose the flywheel and go with EI.

The gas line you see goes from the manifold to the pump diaphram, in lew of the hole in the manifold and the Carb.

I rotated the Carb. so the throttle linkage would line up.

It looks a little different now. I bent the crank and sent it to www.rcignitions.com to have it straightened.

Ralph C. cut the back shaft off, put on a new prop hub and sensor and timed it for me, plus made a new manifold for the Carb.

***

This is what my Toro use to look like http://www.rcuniverse.com/forum/m_3177293/tm.htm

Here is something you will all find interesting. A friend of mine bought 4 or five of these toros off ebay and mine is the first one we have converted. Ok my point is we fired up each of these including mine before deconstruction and they ran great. No issues starting or idling although I will say they have a faster than normal idle. Now when I had starting issues with my carb we swapped out with another carb off another toro. same issue. Very strange..
like I said once you get it running it purrrs but it is a pain in the butt to start. I suppose once I figure out the trick it will get easier.
My question is,,,, is it even possible to adjust the air fuel mix on this carb? My goal is to leave it as stock as possible. The only thing I would like to see is a lower idle. Now it wants to die when I get down to a normal idle speed. I don't have a tach so I don't know the rpm when it dies. I will try to get some pics and figure out how to load them. THis has been a fun project. I will say I am not impressed at all with the ARF senior telemaster. Very poorly constructed and very cheap materials. I guess you can expect much for $250.00 these days.