I recently picked up a box of 10 weed whacker engines for cheap and I want to use one of the engines in my next boat build but I really dont know to much about this engine. The only label on the engine says its a Mcculloch Mac 80 engine with a serial of 00011792. If anyone has any information on this engine regarding cc's or hp or really anything it will be greatly appreciated. Also, when I purchased this box of engines, a few of them were "water cooled" as the guy I bought them from was going to use them in his boats but never got around to it. The thing is though it has a water jacket type cooling that has a few fins machined down and has copper tubing wound around it. would that actually cool it good enough? Thanks

here are a few more pics and then a pic of the water cooling that is on 3 of the engines I have.

It looks a lot like a Mac that I have that is 21cc. Mine has roller instead of ball main bearings. Fine for a boat; not so good for an airplane engine.

AV8TOR

Wholly old timers !!! Thos Mac 80s were clones of an ECHO SRM-200 engine from back in the mid 80's early 90's era.
Ignitions in those are RPM limited at @ 11K if memory is correct. Bore is 32mm stroke 26mm, displacement 21cc's

Hate to burst your bubble, but engines are not worth a hoot as a boat engine, without being able to spin them up to higher rpm you can't get any HP from them ... been there & attempted that .... 20 years ago !!

Transfer ports are really small and casting allows very little opening up larger. 2 bolt cylinder and if i remember the 80's correctly, piston was chrome plated and cylinder bare aluminum. The 95's were aluminum piston & chrome bore.

Sorry to sound so negative, but these engines and the trimmers they were on were part of the start of disposable power equipment and the final nail in the coffin for Mc Culloch corp.

You worry me Scott
Is there any motor you have not tried to hot up
Or even worse are you trying to hot up something that we dont know about yet

haha yea I knew it was a pretty old engine. all the engines I have are from the 80's and 90's. I do have a ryobi 31cc but I dont like how the recoil isnt in back and it is too tall to put in the boat. Im really not looking for like a 60mph boat around 30 is good for me lol. All this is, is a project to keep me busy. Im planning on building the maxcatv1-l. Thanks for the free plans. But yea, like I said, i'm not out for top speed. plus I probably will only be using the boat a couple times a year. So, Im probably just going to use what I have and hope for the best lol.

Yea, been down the road of Small engine mechanics for near 30 years now. From @ 1978 to 1999 worked as a commercial small engine mechanic in a shop catering too loggers and commercial landscapers. If it was built by Homelite, McCulloch. Poulan/weedeater, Pioneer/partner, Echo, Shindaiwa, Green Machine/Zenoah, Honda, Jonsered, Husqvarna, Stihl and countless others .... been there & tweaked on it

I also have an old sears/ craftsman weed wacker engine i'm considering using. Its a kioritz 21.2cc engine that has idk if its points or a magneto thats in the same housing as the recoil which is in the back. It also is about a good pound less then the mcculloch engine. I can probably knock another half pound off. if anyone has any input on this engine let me know lol. thanks

the Ryobi would work ok if you flipped the engine upside down, which would pretty much just involve rotating the pullstart location to the other side. it's limitation is it's crankshaft and connecting rod, doesn't like to survive life above 8000rpm (well, 8000 as a safe limit that is).

kioritz are well built strong running engines, but the ryobi would have more power

Post a picture .. tell ya exactly what you have

here are the pics. the last one is blurry and dark but it still visible. if you need more let me know. And one last question. the way a few of the engines i have have the middle fins machined down and have that copper tubing wrapped around it(pic in first post) would that be sufficent cooling? thanks

I can't answer that question, but if you don't have the fan schroud for that kioritz, I wouldn't run it as is, for air cooling you need the schroud

you do worry me Scott. Vaine , you must remember Scott is a motor head just like me. He competes big time and HP is his game. but sometimes its not all about the HP. As a motor that is probably one of the easiest to work on a convert to marine. it has lots of old articals showing how to watercool it, and the crank is solid with bearings at both ends. its also very compact and has its own clutch which is one of the reasons it was popular.

With that said these motors were around during the start of our great hobby. i have a box-load (40) of them sitting in storage brand new never run. they make great model boat engines and i have even seen a couple that were converted for planes. as long as your not looking to go Mach II. I have several old boats powered by watercooled versions of this Mac/Kiortz engine. they run all day long with no problems . they can run 20-30 mph in 48" hull depending on your set up. its not 50? but its still fun.


these pics are of the first boat i ever built in 1985. it has a mac engine and an AMPs drive on it. Still goin strong today.

good luck

That is a Kioritz/Echo SRM-200DA from the early 80's

A really tough industrial motor too !! ... same bore and stroke 32 x 26 = 21cc
* My first successful marine conversions were done to these exact engines. Still have a box of parts, cylinders,pistons, ignitions, etc.
Hot ticket in the day was to use vertical spark plug cylinder off the PB-200 blower on those cases. Loose the flywheel & clutch and water jacket the cylinder.

If interested in some trick 20+ year old pieces to build one up ? ...... ask, will make ya hell of a deal.

Alright sweet. If the kioritz is a better engine I will definitely use that one. I have 2 or 3 of them that came in that box of engines I bought. Im going to keep the clutch when I first start running the boat just so I can get used to everything and be a little on the safe side. Im pretty much new to rc boats so Im just gonna take things slow to begin with, then take the clutch off as time goes on. Like Nieto said, its not all about hp (well for the time bieing lol) . But Im gonna build the boat then hop it up as time and money comes. I appreciate all the help that I have gotten. IF anyone has any articles how to water cool the engine I would appreciate that too. again thanks for all the help.

Among the parts I have for them, have 2 of the PB cylinders of which one is already modified for an external head and has a water jacket.
@ 4-6 pistons NIB and most low drag single ring ones !! .... xtra rings too. Even a few CDI points conversion chips in there

If you want a major kick in the pants towards running those engines ? ...... $100 + actual ship costs for the lot, and that's a LOT of stuff you can't even buy from echo any longer.


FYI ... if interested

That sounds like a really good deal to me ,id take him up on his kind offer before he changes his mind .
Mart

Thanks for the offer but money is tight currently because Im going to college and class starts next week, but when I get some money to spare and I need the parts I will give you a message if you still have them. Thanks

Just food for thought ...
We are not talking a box of used discards here, MANY are NIB parts and those out of package are like new. There are parts here to built 2 engines and still have some spares.
Basically the spoils of a guy into RC boats who had the access working within the industry to get the best of the best to build this specific engine into a great power plant.

Dam Scott theres quite a few goodies there for the money.
Mart

Mart,

Ya know I have been rat holing this stuff for years !! .... Maybe I should assemble one and install in a double pontoon retrieval boat of some sort. Maybe put into an old hull and sell off as a play boat ?
Damn shame to let it sit collecting dust for another couple decades [:-]

Yea i agree it would make someone a nice play boat or two ,your like me i never throw anything out just in case it comes in.Id sooner give someone something than throw it out or leave it gathering dust.I recently gave someone a spare hull i had lying arround that wasnt quite up to scratch to sell on,it needed a little work but id rather the guy have it than throw it out.Someone would be happy to have those parts for sure.I like the idea of a pontoon retrieval boat there was something similar on ebay ages ago not really a rescue boat more a fun boat but it was quite fun looking.I have to say $100 for those parts seems like a bargain to me,if not build one up and lets see what she runs like.Knowing you it would be a good little runner .
Mart

Funny how the spoils of old school still are spoils [:'(] .... old decrepit & outdated are just paper weights or fishing sinkers in modern eyes.
Sad that where we have come from is so quickly forgotten

By no means is this wisdom, hell I forgot about this stuff too

SHHH Scott or people will start to realise just how old we are .
Mart

I stumbled across this thread looking for Koiritz engines, and damn if I see the same logo as on my mystery engine. Three stacked triangles seems to be the Echo logo. Then the pices in Scotts boxes boxes seem like my engine, in particular I see what looks like the timing module on mine. If Scott or someone familiar with these engines see this could you look at my thread and varify what engine I have, and especially how to remove that timer.[X(]
http://www.rcuniverse.com/forum/m_91...tm.htm#9152905

Thanks
Rod S