rearenginekarts.com

Hi guys,


As far as i know the engines in the mc line were built with the usual manufacturer laziness. Ie: if the part works use it next year.
i've found through a simple number research project that the parts numbers interchangeability of mc 5-91 parts is very good.Asking you guys specific questions has filled in the picture.

Several of us "newbe's" are trying to build mc5 5/6 and 6 motors.
first the flywheel.i'd like to confirm that any 91 series flywheel will work.
true/ false?why
The shroud is different from the later models and i'd like to ask the guys that know to answer some questions.

What we know or think we know:

1. The shroud is different

2.the head was installed with the plug facing the pto side.
true/ false? why?
a.i've been told that the mc 5 5/6 and 6 heads were flipped 180 degrees in later years to protect the spark plugs from chain whip when a chain let go.
true/ false?
b.i've also heard they were flipped because the coil wire on replacement coils was shorter.
true/ false?
c.the likely one that i was told is on the chainsaws people were getting rapped by wet plug wires so mcculloch relocated the plug away from the hand area to stop this , kart motors were changed too.
true/ false?

3. we've been told the shroud is bigger, smaller ect. ect.
my research indicates that the shroud is the same but was modified in later years (a cut out was added) to accommodate the reversed plug direction and taller block.
true/ false? why?

4.the 91 fan and head shroud fit without modification.i know this can be true as i have one that way .
true/ false? why?

5.does filling the opening in the head shroud (with some sort of epoxy) make it look/pass as a mc5 shroud?
true/ false?why
6.Also, can someone please, please ,please post some really good pictures so we can actually see a mc5 shroud.(maybe Ed?)

like i said any help is really great.

thanx dave

Dave, Hope these help. The first 3 are my restored 5 and the last 3 are Lynn Haddocks NOS Mc5
Email me your Phone number and I would be glad to call (its free for me) and talk early engines with you rcubel@hotmail.com

Ron Cubel

http://img.photobucket.com/albums/v518/ ... C-015F.jpg

http://img.photobucket.com/albums/v518/ ... C-014F.jpg

http://img.photobucket.com/albums/v518/ ... C-013F.jpg

http://img.photobucket.com/albums/v518/ ... -1022f.jpg

http://img.photobucket.com/albums/v518/ ... -1011f.jpg

http://img.photobucket.com/albums/v518/ ... c-105f.jpg

Ron,
many thanx
the pix are priceless.
all my questions now are pretty much answered i guess.
i can see that a chainsaw cover was used on the 5's because of the kill switch.
i also had noted that many of my covers looked like they had been cut out with the corners drilled.
the stock mc5 has drilled holes in the same place , i suppose for access to the allen screws on the head underneath.
as i've said manufacturers love using the same stuff over and over.
i'd bet that when they changed the design they had a ton of covers already made so they just "fixed them ".
couple of new questions.
the mc6's seem to have their head in the newer position.with cut covers, is that a correct thought?
2. what tilly was put on the mc5's?
anyway , i will be getting in touch as i can use all the help i can find.
thanx again dave

Mcculloch used the Tillotson HL-63B carb on the Mc-5 which was a 1-40/1-50 series powerhead with 6.5 to 1 compression assembled with a 1.375" stroke tapered PTO crank and the third ports were drilled. Gear drive powerheads used tapered PTO cranks and Mcculloch adapted that style crank PTO for their kart engines. 1-50 saws used the Mcculloch magnesium carb with a manual choke. Later models of the series, 1-51 etc. either used the Tillotson with a manual choke or else the priming (flatback) Mcculloch carb. Adding the back 3 ports to a saw block might take some practice.

Tom,
very cool information .
i will add it to my little book/file on mcculloch engines.
it is a wonder to me how much info is hidden away until you ask.
i have some of those carbs in my pile-o-stuff i've saved from saw breakdowns.
i also have an extremely stuck and corroded 1-40 block that i can use for practice if i ever persuade it to come apart.
i've been soaking it for several weeks in the hopes it will loosen up enough to dis-assemble.
please keep this thread going guys newbes need all the help we can find.
thanx dave