I can pick up a new Mac 28cc weedwacker new ,cheap. Will they make a good conversion? I haven't seen it yet. Anybody have any experience with this engine? thanks for any help.

YES, Great Engine to convert. As far as I am aware all you'll need to buy is a Propeller Hub Adapter. I converted a 21cc Mac for my Taylorcraft:

http://www.skylites.freeserve.co.uk/photogal/pc.htm

I know someone else who's converted a 28cc for his Hannibal.

One thing that made me shy away from McCullochs is that the muffler is held on with springs, not bolted on the block like most other engines.

Volfy

Yes, I find that strange for such a company. BUT, in practice I've had no problems with any of the muflers. One does'nt seat properly but after a while the gap seemed to fill up and seal with carbon. Still think they are great engines and the most freely available in the UK.

CH ignitions are high on Macs and sell conversion parts,mounts,mufflers,and ignition conversions for them.....
I think Carr do too........

I guess it's okay if you keep the stock muffler, but using an aftermarket one might take a little work.

I was hoping to go with an ignition setup. How is the mag setup on these? Will I loose or gain weight switching to ignition?

I have a ABBELL muffler from C-H on my two McCulloch 32's. I retained them with the spring and they do just fine.

The C-H ignition saves some weight. It takes weight off the nose of the engine which is more important. It makes the engine hand startable.

Jim

Is the 32 a weedwacker or a chainsaw unit?

They make both and I have both but the ones I was referring to were weed whacker versions.

The Chain saw has a bolt on muffler

I see C&H has a conversion kit for it. Any idea what it will weigh all said and done? Muffler,battery etc.

I never weighed mine. It's heavy compared with a glow engine though. It looks like it was intended to be a model engine because all the unecessary junk unbolts from it. They start and run nice. I put a 1/2" carb on them though.

The electrics beyond what C-H supply's is just standard radio stuff except the battery is a 1400.

I have a 4* 120 I would like to change over to gas and hoping this might be an inexpensive way to do it.

Hi
You can check this link: http://www.rcfaq.com/
follow the "weedwacker" link
They do a step by step conversion of a McGulloch 32 and a Poulan 46

Also see http://www.geocities.com/capecanaver...1071/4star.htm
for an article on putting a Ryobi in a 4/120.
I fly one of these combinations with a CH conversion to get rid of the flywheel and coil and a pound of weight but it can be done either way......

Kevin;
How did your 4* balance with the Ryobi and ignition? Did you have to move the firewall back or move servos or anything? I have a new Ryobi sitting here. thanks; Jim

I picked up the new Mac weedie today. they advertised a 28cc but the unit says it is a 32. Been running it some in the eater to break it in. Will tear it out later and order up the needed stuff from C&H. I already have an ignition and syncrospark unit out of a plane I am restoring so all I need is the mounting stuff. Anybody have any prop #s or recommendations for this engine? Thanks

I moved the firewall back only enough for the extra length of the Ryobi,cut the cheek cowls off and made up a glass nose with the Ryobi mounted inverted and fitted with a Bisson muffler.
The engine battery and black box are snugged up against the firewall inside the fuse,and the R/X and other battery are at the back of the wing mount area.
Three servos are mounted in the tail two for elevators and one for rudder.
With this setup the CG landed smack where it had to be with no extra ballast......
If I can ever master sending photos I ll file some pics here.....

The 18-8 seems the best. I get 7400 with a stock C-H 32 but with a 1/2" Walbro carb on it. I have another 32 that Terry at C-H modified. It turns the 18-8 at 7600. It also has a 1/2" carb. They both look like they were designed to be model engines from the beginning. I have the Abbell mufflers on them held on with the original spring retainers.

Jim

Kevin;
Which Bissom muffler are you using? Will work on a Ryobi and Mac both? Thanks