computermonkey

My Feedback: (90)

Hello everyone.
I have a Webra Bully 35cc on glow (has a Walbro HDA-6a carb). I have purchased a Webra ignition unit from Pe (thanks Pe) and a Walbro WT-540 from someone else.

Here's the information I am looking for, what chain saw model did Webra use for the cylinder and piston? I think they are from a Husqvarna chain saw.

I have seen in past ads the Webra Bully with Rcexl and DA ignitions on them, but they where new engines. Does any have this set up that would post?

I also noticed from the pictures that the front crank area has web bracing and the drive washer does not have a skirt on it. Mine engine does not have the web bracing, plus the drive washer has a shirt that covers some of the front crank housing. I also noticed the material between the carb and cylinder is made of a different material, my is aluminum. Is the engine with the web bracing a earlier make?

Being my engine has the skirt on the drive washer I would think it having the Hal sensor at the front of the crank housing would be difficult. What if you remove the brass plug and put the Hal sensor where the factory one would goes? Anyone try this?

Also if anyone has any parts/engines for this or older Fox engines can you please IM me.

Thank you.

pe reivers

Ralph, please be aware that the ignition does not have a Hall sensor, but responds to the vicinity of steel! Thus it will see the passing of the crankpin and react accordingly!
The system is very old, and very industrial. It should give you good service. You could even make an aluminium hub with a steel insert for the sensor to read. No magnets please. Just a steel washer with a bent tab will do.

computermonkey

My Feedback: (90)

Thank you Pe for that information. I haven't pulled the brass plug yet so it good information to know. I see why the engine that have aftermarket ignitions have the sensor by the prop.

Antique

My Feedback: (4)

The ignition engines I have here have a small magnet embedded in the crank pin for the sensor that screws iinto the brass plug hole...No magnet, no spark...
I made 2 1/4 inch thick aluminum rings about 1 3/4 diameter...Press a 3/16x1/16 magnet into the flat side of one, press it onto the hub..Press the other one onto the round part of the front case about .030 from the front one..Mill a slot for the sensor in it, epoxy a sensor bent over 90 degrees into the slot....Check the operation of the ignition before making anything permanent....If you make the hub sensor a slight push fit you can set the timing no matter where the hub fits on the crank...use one or two small setscrews to lock it in place...
The HDA6 carb came with the ignition versions, the glow had a Tillotson....

computermonkey

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Anybody have any information on what Husqvarna cylinder and piston the Webra used?

computermonkey

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Surely there is someone that has knowledge as to what cylinder and piston this engine used.

Question do you think this engine on gas would fly a WildHare 35cc airplane good?

Antique

My Feedback: (4)

Diego Lopez flew a 35 lb scale warbird with one of these....

computermonkey

My Feedback: (90)

Well I checked with 3w, they confirmed that the cylinder and piston used on their 35cc engine was the same but they didn't know what chain saw it came from.

Also have a question, does anyone know of a cdi advance ignition that will work off a magnet set at top dead center. RCExl has to have their magnet set at 28 degrees. Seems like the prop would kick back at the setting.

tkg

My Feedback: (1)

Put the magnet and sensor on the front. Its easy and works just fine. The ignitions that trigger at TDC have had a great deal of reliability problems, no so much as a result of the design, but as a function of a crappy built product.