j301

My Feedback: (12)

I did as much research as I could and am still stumped so I would like to ask for some help in I.D.ing this motor I came across.

From what I found, the jug was used on everything from a 40cc Jonsered BR 420 chainsaw (Swedish I think?) to one of the Sachs engines (4.2 from what I found), to a 3W35, which is my best guess at what this motor might be. I even found the ID # on a German board that talked, from what I could gather, about it belonging to a 26 or 28cc something or other. That # is 1211001 927, preceded by ++1A.

The carb is a Walbro marked 21-245. At fist I was told it was a G38, so that carb made sense, even though those #'s don't show up on any Walbro charts, I was able to narrow it down to an HDA 48. The more I looked at it, the more I disbelieve its anything Zenoah.

Its obvious that it has been converted to EI, and the module is an older (almost military looking paint job) CH ignition unit. I rebuilt the carb and am able to get the idle down to 1300 and it maxes out at about 6500 on a zinger 18/10, which is the rpm a 3W35 should max at but with a 20/10 from what I read.
Anyone recognize this thing, and if so, what should it run? It also seems to spit fuel out of the front of the carb at full throttle (sustained, not just at run-up).
Thanks for the help,
Jim.

Ed Vollmer

My Feedback: (14)

From the case back it appears to be a 35cc Webra Bully. Originally it had a Webra ignition on it and the pickup wire has been cut off. It appears to have been modified (perhaps by C H Ignitions) to use an ignition that actually works.

j301

My Feedback: (12)

Thanks for the info Ed, did a quick search on the engine and from what I see I think you are right. Its an "oldie but a goodie" from what I can discern from the reading I found. Still cant find much in the way of specks on it though. Seems to run strong, but I am guessing its about 500 to 1000 rmp shy of what it should be turning.
Guess I'll keep toying with it to see if I want to brave sending it up.
Thanks again.
Jim

Pelle Gris

My Bully is converted to Rcexl ignition, and did just around 7800-7900rpm on an APC 18x10.
Silencer was a 50cc can originally from a DA 50.

j301

My Feedback: (12)

Thanks Pelle, I checked the timing and its at 30 deg btc, stock carb with a rebuild and a ch ignition. What might be holding this motor to 6500 do you think?

a70eliminator

I wonder if the substitute muffler has anything to do with the carburator eruption, and the rpm limit due to backpressure.

j301

My Feedback: (12)

You know I was thinking about that, the "muffler" (or exhaust redirection unit I should say) looked funny to me anyway, but I've read about people testing/running this motor without one all together. I agree it seems too small, but I am having problems even finding something that could take its place. Have to expect these issues when dealing with equipment manufactured the same time Micheal J Fox was traveling around time in a DeLorean...!

Pelle Gris

Mine did 8200rpm open exhaust, and 7900 with the DA 50 can on a 8,66in header, all on the APC 18x10.
I don´t know the type of "muffler" that´s attached, but it does not look like it does much in the way of silencing the engine, so I would guess that you might as well run it without. It could be that this is holding the engine back.

j301

My Feedback: (12)

I read in another thread that you had changed your carb to a WT610, did you ever get that to work for you? One problem I am having is that the power and idle needles on mine (HDA48) are missing the washer/o-rings which I think would lead to some issues, unless this carb just doesnt need them (its actually marked 21-245). I can get a 610 fairly cheep, but if I could just find the o-rings that would be even cheaper but no one local has any clue if the o-rings are interchangeable, etc. Very frustrating, but the carb is rebuilt so I would kind of like to see it through, plus if the 610 is going to cause issues I would be no better off. It seems par for the course when you get a "good deal" on a motor!

daveopam

My Feedback: (9)

Have you checked to see if the muffler has been port matched to the cylinder? Might be a few hundred RPM there.

david

earlwb

The carbs on these types of engines tends to spit fuel out of them when running. That is normal. You can improve the running by using a short intake stack on them too. The intake stack helps to reduce the spitting and stabilize the gas vaport cloud that forms right outside the intake of the carb. So the engine tends to run better and it helps the fuel consumption too.
Yeah I would agree it looks like a Webra Bully engine too. I would double check what looks like a wire on the back of the crankcase to ensure it isn't an air leak. I couldn't tell it if was a wire or a tap for a pulse pump or something.

j301

My Feedback: (12)

That is a good Idea, I will do that next. I've heard the bolt pattern is the same as a G45, anyone know if this is accurate?

From what I was able to find, I think Ed is correct that it is from the old ignition pick up used on the original module. From what I understand it was a bad design. I will double check to see if its leaking air, every little bit helps. I did look into velocity stacks and I am sure the Zenoah will fit, just have to get one ordered. Thanks for the ideas. I would love to get to a point where I could trust this motor in the air. It's heavy, but I am in to war birds anyway and I figure this would be good for something like an ESM F4U or Bearcat.

Thanks for all all the help so far!

j301

My Feedback: (12)

I checked the wire, no leaks, checked the muffler and it looks like whoever made it did a good job making the case; drilled two holes for the mount screws, then threw it outside to let his pet beaver gnaw a hole in it roughly where its supposed to meet the exhaust port (it must have gotten to eat the gasket for desert as there was none). Looks like I may go with a WT610 carb and give Wackerengines a call and have them make me up a new muffler unless anyone has any better ideas for a muffler that would fit a g38?.

earlwb

A lot of people leave the exhaust gasket off as the softer gasket material tends to compress and then the mufflers screws come loose on you.
The Pitts style mufflers like on your engine are quite common. Several companies make them too.
Many people converted them over to use the modern CDI ignition modules. No fuss no mess going that route, plus you get to pull off some of the heavy items on the front of the engine too.
Walbro seems to have made something like 10,000 different carbs. Mostly it is the jet sizes and bore size is the main difference. Different manufacturers would order carbs to their specs for a engine and get a special part number assigned, so that the carb would be for their particular engine. Helps make people buy parts from you that way.

captinjohn

My Webra Bully has a Bennit exhaust on it with 2 down pipes. Removethe sparkplug and hand prop it over. My engine has high crankcase compression....more than any engine I ever have tested. With the sparkplug in,it should have very high compression. I would remove the cyl and see if the ring is partly stuck in ring grove. If cyl looks good ...make sure piston ring is free without too much end gap. If needed....get a Frank Bowman ring and you may have one of the smoothest engines around. Post a photo with a good side view so we can see entire engine with prop hub in view. The views you posted does not show propshaft and pick-up. Best Regards Capt,n

j301

My Feedback: (12)

Hay captinjohn, I took the plug out and turned it over. It seems to have more case compression then any of my other engines, and with the plug in it turns very smoothly and has good compression, I don't own a compression gauge, but it seems quite good by hand. I've ordered a new muffler and carb and am betting that will wake this guy up. Before I install those I am going to disassemble and clean it, and check the ring and the rest of the innards, and pick up a new plug as well. I would normally have done that first, but from how the mechanics feel at this point I was confident enough to get the parts coming.
Thanks for the input, and now knowing about Bowman's rings is a great resource to have as well. Here are a couple of side shots and one of the prop hub. You can see where CH attached the sensors on the prop shaft. Looks a bit rudimentary but its seemingly effective.

j301

My Feedback: (12)

The saga continues: So I replaced the plug, put on a JTEC muffler, changed out the gaskets on both sides of the carb, replaced the old carb with a WT610, checked the liner and ring. The only way the motor will stay running with the 610 is if it is choked. I opened up the carb and it looked like the diaphragms could need replacing. The carb is unused, but likely has sat for a while. So I got a fresh rebuild kit and cleaned out the carb. Same issue; engine runs through its prime then dies, choke it and I can coax it to idle, but then it dies if the choke is off or under acceleration.
To see if the new gaskets and muffler helped, I put the old carb back on and the numbers did not improve. I can get 6500 with an 18/10, but its not dependable under acceleration. I have to richen the top end to get through the mid range (drops rpm to about 6200). That is why I wanted to try the 610 as it has a pump that should solve this issue, if it ran anyway. I just dont know what else to try at this point. It a bummer as from what everyone is saying it should be a great motor.

Ed Vollmer

My Feedback: (14)

I had a couple of these back in the day when they were the hot ticket. Mine were notorious for case leaks. Do a soap bubble test on the area where the case splits. Take the plug out and daub some soapy water on the split while rotating the crank so that the piston is on the downstroke. That creates pressure in the case and will blow bubbles if the case is leaking.

From your pix it looks like it is at least weeping oil.

j301

My Feedback: (12)

Thanks Ed, if the compression from the bottom of the piston is leaking out the case, I guess this could cause issues with the pulse for the carb? Is there a gasket there? How did you fix yours?
I will give it a shot and see what happens.

Ed Vollmer

My Feedback: (14)

It has been a long time but I likely used a film of Permatex Ultra Copper. I would look for a leak between the intake port surface and the carb also.

Unless it is a major leak I doubt that is causing the pulse problem just because of the volume differential between the crankcase and the pump chamber in the carb. Can you see fuel drawing in the line as you crank the engine? If so, the pump is working.

One thing to check on the carb is to make sure the check valve gasket flappers rest flat against the ports. The check valve gasket may be reversed. I would install a re-build kit in the carb just to be on the safe side.