Conversion of McCulloch 28cc, can someone help?
01-03-2006 | 08:02 PM
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From: East Coast
Conversion of McCulloch 28cc, can someone help?
Here is my McCulloch 28cc weedeater engine. I tore most of it down. Can anyone help me in telling me what needs to be done to it to convert it. I would like to do it myself if I can as I like doing stuff like this. A few questions I have:
-- What needs to be taken off?
-- What needs to be added?
-- What needs to be cut or modified?
-- Is the carburetor ok or does it need a different one? The name on it is Zama, if it isn't going to work, I can obtain a Walbro from an 18cc but not sure if that will work as it is from a smaller engine, or will it? The carburetor, if you look at the picture of it, a choke that is connected to the carburetor, it is a lever that is manually moved. Does this get removed or does it stay?
I appreciate any help I can get, and I thank you in advance for your help. Below are the pix of the engine.
-- What needs to be taken off?
-- What needs to be added?
-- What needs to be cut or modified?
-- Is the carburetor ok or does it need a different one? The name on it is Zama, if it isn't going to work, I can obtain a Walbro from an 18cc but not sure if that will work as it is from a smaller engine, or will it? The carburetor, if you look at the picture of it, a choke that is connected to the carburetor, it is a lever that is manually moved. Does this get removed or does it stay?
I appreciate any help I can get, and I thank you in advance for your help. Below are the pix of the engine.
01-03-2006 | 09:03 PM
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RE: Conversion of McCulloch 28cc, can someone help?
Here is a picture of the finished engine from the Carr Precision Site..... And a C-H version
To work better, you will need a carb from a small chain saw but the stock carb will work with few mods.
You will need to cut down the bolt-on bracket that holds the coil toremove any unnecessary metal as shown in the picture if you are going to use the flywheel? Also the outer fins on the flywheel will need to be turned off.
Carr Precision or C-H ignition sells a back plate mount adaptor or you can make your own fro 3/16" aluminum. There is an existing plastic part of the back plate that needs to be cut down the where it is no bigger than the engine crankcase.
Yours has a different shaft than all of mine have had. It looks like it was a blower or non clutch type whacker? I would show a picture of this to Dave Carr at Carr Precision or Terry Grant at C-H so they can get the right hub for you?
http://home.att.net/~carrprecision/Page3.html
http://www.ch-ignitions.com/
Enjoy,
Jim
To work better, you will need a carb from a small chain saw but the stock carb will work with few mods.
You will need to cut down the bolt-on bracket that holds the coil toremove any unnecessary metal as shown in the picture if you are going to use the flywheel? Also the outer fins on the flywheel will need to be turned off.
Carr Precision or C-H ignition sells a back plate mount adaptor or you can make your own fro 3/16" aluminum. There is an existing plastic part of the back plate that needs to be cut down the where it is no bigger than the engine crankcase.
Yours has a different shaft than all of mine have had. It looks like it was a blower or non clutch type whacker? I would show a picture of this to Dave Carr at Carr Precision or Terry Grant at C-H so they can get the right hub for you?
http://home.att.net/~carrprecision/Page3.html
http://www.ch-ignitions.com/
Enjoy,
Jim
02-22-2006 | 04:27 PM
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From: bbvbv, UNITED KINGDOM
RE: Conversion of McCulloch 28cc, can someone help?
Hi im new to gas engines.
Could anyone explain the pros and cons of 'stock ignition' as opposed to electronic ignition.
I have the McCulloch 28cc. What props do others use with this (flying an edge 540 72") I was thinking of an 18x6 ?
Thanks
Stu
Could anyone explain the pros and cons of 'stock ignition' as opposed to electronic ignition.
I have the McCulloch 28cc. What props do others use with this (flying an edge 540 72") I was thinking of an 18x6 ?
Thanks
Stu
02-22-2006 | 09:06 PM
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RE: Conversion of McCulloch 28cc, can someone help?
The "28" would use a prop in the 18-6 to 18-8 range.
I have some of them. The converted ones have the C-H ignition. I thought it looked cool. They run perfect.
The original magneto flywheel ignition is cheaper, weighs more
Battery ignition gives just a little more power, starts easier, weighs less, and costs a lot more. The battery powered ignition makes the conversion go easier if you buy from C-H. They have all the other parts for your conversion also.
Enjoy,
Jim
I have some of them. The converted ones have the C-H ignition. I thought it looked cool. They run perfect.
The original magneto flywheel ignition is cheaper, weighs more
Battery ignition gives just a little more power, starts easier, weighs less, and costs a lot more. The battery powered ignition makes the conversion go easier if you buy from C-H. They have all the other parts for your conversion also.
Enjoy,
Jim
02-23-2006 | 08:54 AM
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From: Keller, TX
RE: Conversion of McCulloch 28cc, can someone help?
Here are some pics of my Mac 28 conversion. The conversion parts are from Carr Eng, except for the muffler, from Ken Lambert. Milling the fins off the flywheel was done by a fellow club member with a lathe, but this can be done by Dave Carr, also. I also put on an 11mm walbro carb. The combination works well, giving 7850rpm on an APC 16X8 prop on the first tank, then over 8000 as it begins to break in.
02-08-2010 | 05:24 PM
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From: Poplar Bluff,
MO
RE: Conversion of McCulloch 28cc, can someone help?
I have converted severial wacker type engines for RC airplane use. I use C&H ignitions, and have execelent results with them. You can also buy the prop adapter and the mounting plantes from them. They also sell the twist intake manafold, which is a must with the Momelite engines. If you look long enough, you can find Homelite wacker engines for free. Most are 25 CC. You can buy a cylinder and piston kit to up that to 30 CC. Although these engines are low output, with low compresion ratioes, they respond well to a little port work. Mainly the exaust port. In stock form, they don`t breath well. The factory builds this into them for safety reasons. Most will run all day wideopen, with no load, and not blow up. Raise the exaust port 1/4", install a bigger carburator, and a desent free flowing muffler, and that all changes. Set the ignition timing at 28 deg advanced, thats plenty. Mine will pull a thined down 20 X 6 wood prop at 7600 RPM. With a tuned exaust and a 18 X 10, 8300 RPM. I have been flying this engin for two years now with no problems.
Cropduster48
Cropduster48
02-08-2010 | 05:30 PM
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From: Poplar Bluff,
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RE: Conversion of McCulloch 28cc, can someone help?
ORIGINAL: cropduster48
I have converted severial wacker type engines for RC airplane use. I use C&H ignitions, and have execelent results with them. You can also buy the prop adapter and the mounting plantes from them. They also sell the twist intake manafold, which is a must with the Momelite engines. If you look long enough, you can find Homelite wacker engines for free. Most are 25 CC. You can buy a cylinder and piston kit to up that to 30 CC. Although these engines are low output, with low compresion ratioes, they respond well to a little port work. Mainly the exaust port. In stock form, they don`t breath well. The factory builds this into them for safety reasons. Most will run all day wideopen, with no load, and not blow up. Raise the exaust port 1/4'', install a bigger carburator, and a desent free flowing muffler, and that all changes. Set the ignition timing at 28 deg advanced, thats plenty. Mine will pull a thined down 20 X 6 wood prop at 7600 RPM. With a tuned exaust and a 18 X 10, 8300 RPM. I have been flying this engin for two years now with no problems.
Cropduster48
I have converted severial wacker type engines for RC airplane use. I use C&H ignitions, and have execelent results with them. You can also buy the prop adapter and the mounting plantes from them. They also sell the twist intake manafold, which is a must with the Momelite engines. If you look long enough, you can find Homelite wacker engines for free. Most are 25 CC. You can buy a cylinder and piston kit to up that to 30 CC. Although these engines are low output, with low compresion ratioes, they respond well to a little port work. Mainly the exaust port. In stock form, they don`t breath well. The factory builds this into them for safety reasons. Most will run all day wideopen, with no load, and not blow up. Raise the exaust port 1/4'', install a bigger carburator, and a desent free flowing muffler, and that all changes. Set the ignition timing at 28 deg advanced, thats plenty. Mine will pull a thined down 20 X 6 wood prop at 7600 RPM. With a tuned exaust and a 18 X 10, 8300 RPM. I have been flying this engin for two years now with no problems.
Cropduster48
