StZ

Hi all,

I have a DLE 30cc with a walbro carb on it. The choke is spring loaded and it is only activated (ie fully closed) when the throttle is at idle. For this reason I must install a servo to activate the choke from the t/x. Having the throttle at idle I would probably have problems priming the engine, hence starting it, not to mention the extra servo, weight etc. What I would like to do is to replace the choke shaft with one that has the indent and the spring/ball to keep it in place whilst open or closed. I had a look at the Walbro web site but the model of my carb is not listed! I would appreciate if you can help me finding the correct part numbers for replacing these parts on the carb.

Thanks
StZ

All Day Dan

My Feedback: (5)

Start here. Dan.
http://thecubden.org/thecubden/how-t...lbro-choke-fix

All Day Dan

My Feedback: (5)

Get the correct parts from here. Dan.
http://wem.walbro.com/walbro/group2.asp?FamilyName=WT

Truckracer

My Feedback: (19)

You could modify the choke shaft for a ball detent in both positions. If you remove the shaft, it will be clear what you would have to do .... and be sure to grind off the swaging on the threaded end of the choke plate screw before removal or you may destroy the shaft.

With this all said, I really wonder what you are trying to accomplish. Most of us get along just fine with the choke configuration as supplied by Walbro or one of the Walbro clones. If there is interaction between the choke and throttle shafts as there is on some Walbro models, for RC use these are disabled or removed as necessary for independent operation. If replacement shafts are required, you might find what you need in the used engine pile at a small engine shop if such a thing exists in Greece. Otherwise it may be a crap shoot to find new replacement parts that will accomplish what you want though you might get lucky the first time around.

All Day Dan

My Feedback: (5)

Truck, I got the correct replacement shaft, ball and spring from one of the online Walbro parts suppliers with no problem. Even if you grind away the metal parts to disable the choke from the throttle you are stuck with a choke that has to be held open by another servo. This is an undesirable situation for those of us who do not want to bother about carrying another servo or don't have the extra channel. Dan.

Truckracer

My Feedback: (19)

I remember what you had to do on the new WT-76 variant but I'm not quite sure the op is facing the same exact problem. Could be, just not clear from his explanation. I have not seen a choke shaft that has ball detents both in the open and closed positions though. Most just hold the choke open and only offer a bit of friction in the closed position. They could exist though.

StZ

Thanks Dan,

I have already seen this page and that is how I got the idea of the choke fix.

StZ

I had a look and I cannot find the parts for my carb. From model no 758 goes to no 760. There is no 759 reference!!!
That is why I posted for your help in this forum.

StZ

Diss-assembly of the choke will be no problem as what it has to be done. The main problem is the spring and ball that is required to do the conversion properly.
The reason for wanting to modify the carb is the extra servo that is required, the extra channel on the r/x, weight and also there is something else that can go wrong with the model. The simplicity of the manual choke is not compared to the alternative. Also as I mentioned I do not know if I would have problems priming the engine and starting it with the choke closed and the throttle at the idle position. As far as I know the starting procedure is to fully close the choke go to WOT and prime until you get an ignition, etc. etc. I do not want to spend most of my time trying to start the engine every time I go to the field.

All Day Dan

My Feedback: (5)

Here are the part numbers for the WT-76-1. They may be the same parts for all the WTs. They are cheap enough to get just to see if they are the right ones for your carburetor. Dan.

Shaft 40-919-1
Ball 89-13-8
Spring 98-162-7

Truckracer

My Feedback: (19)

Not trying to agitate but was wondering how that Walbro model happened to end up on the DLE30. Did you have problems with the original Walbro clone? If so and you had the original carb the parts would probably transfer to your new Walbro.

StZ

Thanks Dan. I will give it a try.

StZ

The DLE was bought from a forum. It is brand new and it has never seen fuel. I do not have another carb to change or use the parts. It did came with the original box, instructions, parts, etc, etc.
Another DLE bought couple months back, had a different carb on it with the usual choke. It has been installed on a model without any problems using manual choke configuration.

StZ

Greetings all,

I have made the conversion to the carb with the choke lever having an indent for the ball/spring, which were also installed. However there is a catch: the lever has only one indent for the ball to sit, this is when the choke is closed. When the choke is open I have used the spring from the other lever to force the choke open when rotated. My problem now is the installation of the wire to the front of the engine. As you can see from the photos the choke lever has a long plastic arm. I have made a hole to install a 2mm steel wire to pass through the engine case. However the force needed in combination with the position of the lever makes it difficult to position the choke to the desired location (open or closed). I do not know how to make this work. I cannot remove the plastic from the choke lever without damaging it. Any suggestions ?

Truckracer

My Feedback: (19)

I would cut or otherwise remove the plastic part from the shaft and replace it with a standard aftermarket throttle / choke arm like you have on the throttle. This will give you more linkage and position options than the plastic part. As noted in post #6 above, most choke shafts only have a ball detent in one position which is usually open.

StZ

I was thinking of cutting the plastic to expose the shaft but I do not know what I will find below the plastic. Will I be able to use the shaft as you mentioned? Will it be at the right size/length etc?
That is why I posted on the forum to see if anyone else has done it.

As far as the detents is concerned my other DLE 30cc engine has a carb choke shaft with two indents, one on open position and one on closed position securing it firmly as required.
This one has one indent. Who knows maybe there are some with three or four indents.

Truckracer

My Feedback: (19)

I don't know what the shaft will look like under the plastic but wouldn't hesitate to explore whats hiding under the plastic. The plastic would be completely worthless to me in its current configuration.

You're a modeler ..... you can modify it and make it all work for you!

All Day Dan

My Feedback: (5)

The choke shaft I have for the WT-76-1 carburetor, 40-919-1, has one detent that is for the open position and has its own arm swaged on. The choke is held closed by friction between the ball and shaft. There is a spring on your choke shaft between the plastic handle and the body of the carb, what is that for? Maybe it should be removed. Dan.

StZ

Dan,

I placed the spring on the shaft in order to have always a tension to the open position of the choke. There was no spring on this modification so I removed the one from the initial shaft (the one without detents).
As I mentioned my main concern here is how to make the most easier/appropriate link for the choke to operate from the front of the airplane, inside the cowl. I could try to remove the plastic all together but I would like to avoid that if I can.

All Day Dan

My Feedback: (5)

Here is an image of the choke with the single detent shaft as installed by Walbro. The detent on the shaft keeps the choke open and the groove around the shaft keeps it in place. I have seen guys using a small pushrod to their choke from the front of the cowl. They made up aluminum brackets mounted to the firewall or a convenient spot on the engine to support the rod. In its most forward position the pushrod was always behind the prop. Take an image of you engine on the firewall and what your cowl looks like. Maybe one of the guys can give you some advice. Dan.

StZ

If you have a look at my post no 14 you will see the position of the choke plastic arm as well as its size. The handle is quite long and its diameter small. Whatever link I have tried requires quite a force to make the choke arm turn to the closed position. When trying to open the choke it is easier since there is the spring acting on it helping it to move towards the open position. Any suggestions?

michael wood

My Feedback: (1)

Use A servo to operate the choke to start and shut the engine off. Its easy use channel 5 (landing gear switch) to open and close the choke

you can also set the failsafe on the radio to close the choke if the radio has a failsafe mode Have you every tried to fly A 24oz tank of fuel out at wot and no way to shut the engine down its not fun All my gassers have A choke servo to start the engine and stop the engine if I need to in flight and on the ground

StZ

see my first post

Truckracer

My Feedback: (19)

Here are a couple of photos of a VV 20 and its manual choke linkage. This is the only engine I had handy to take photos of. I have very similar linkages on DLE30 and 35 engines. The geometry of the linkage is a bit different on the 30 and 35 engines but they are basically the same as the 20. This 20 uses aftermarket throttle and choke arms though I have used fabricated solder on or bolt on linkages on other engines as needed. Each engine presents its own challenge. On larger single cylinder engines I prefer to use a choke servo rather than mechanical linkage. I would bin that plastic piece in a heartbeat! Hope this helps.

StZ

It seems that I would have to destroy the plastic knob. One question is however the arms that you are using do they fit exactly on the axle? On mine there is a slight difference in the diameters and the aftermarket arm does not sit parallel to the axle. I have tried to center it with the two grub screws but it is not possible (of course). Where did you buy yours from?