New Mac .21?

[jaso]

Hi all, just gave my new .21 rigger it's first outing today. Only got to run for about 10 mins total on the water due to time restrictions.

My question is about the set up and run in of my new Mac.21 .

What sort of run in procedures are people using for the Mac and how many tanks before it loosens up a little?

Also I think I remember reading some where about the .45 needing a very open carb at idle ( about 1/3 open) and very rich on the bank to supply enough at WOT on the water. Is this also true for the .21? Do you need large size fuel line or is medium sufficient? I'm running a smaller prop for run in and I've heat cycled it a few times in the shed but I think I might need a little more to help it along.

I have drilled the stinger on the parabolic pipe also.

It sound like a ripper little motor out of the box, Can't wait to get it realy hummin with a good prop and see what it does!

Thanks for any comment in advance.

 

[shoboat]

Jason,

Not too much prop, remember the MAC 21 likes to spin RPM.

Just keep running the motor the Piston and Sleeve will loosen

up the more you run it. I just run the first few tanks really

rich then I slowly start to lean on the motor,I have two that

are working real well. As for the pipe setup, I have all the

Parabolics and I think the Nitro pipe with a stinger is still the

way to go for power and response. And yes they like a rich

setting at idle,I have tried four different carbs on mine and

I have found one to be better than the rest,it was custom-made

for my application. O' Yeah for a 21 rigger try a H-4 you will not

be disappointed.

Thanks,

Mark Sholund

Props-4-U

 

[jaso]

Thanks Mark.I'll get a H4 and give it a go when it's a bit more run in. Anyone else share their thoughts on the Mac .21 or is Mark the only one with any info they want to share? :blink:

 

[Don Ferrette]

H-4 is a good prop for your 21 rigger & MAC 21, works real well on mine!

 

[jaso]

Don, much difference between ya new Mac and last Years one?

 

[John Knight]

Jason,

My son has a rigger with a MAC 21 with a parabolic 21S (short) pipe. Starts well, runs about 25% open for idle. Launches about 1/3 idle. Use a OS remote needle (no 3rd channel yet) and standard fuel lines. Have used a H-4 (pitched up) and a H-5 as well. Just tried a new ABC 1716 prop on it and gained 3-5 mph. I cannot use a H-6 or H-7 on it with a MAC engine. I have a 20 rigger with a NovaRossi and can pull the H-7 with no problem. MAC's generally have less torque than a NR. So smaller prop is the way to go with a MAC. I have an 1816 that I will try this weekend on my rigger. The MAC would not pull it. Close to 10 mph slower than the 1716. Can't live with that.

Do not know which parabolic you have. The 21S can give more rpm's if you can get it dialed in. More difficult than a standard parabolic to dial in and is more sensitive on the needle. The MAC seems to run better with the 21S and my NR runs better with the std parabolic. I need more test time to try the 21S again on mine.

 

[shoboat]

John,

Unless you reduce the 1816 it will not work to well with a MAC 21 motor.

Your Nova Rossi should have no problem with the 1816 or a 1818 prop.

I think you will find most MAC 21's will like the 1714 and 1716 propellers,

and the Nova Rossi 21's will like the 1814,1816,and 1818 propellers. Just

a general rule so far, testing the two different series props. John we

are finding better handling characteristics also with some of the new ABC

propellers.

Thanks,

Mark Sholund

 

[Preston_Hall]

I've heat cycled it a few times in the shed but I think I might need a little more to help it along.

Best break in is in the water. You can heat cycle while running by removing the water line and run rich. Rip thru the turns and cruise the straights. Then start running a lap wide open and cruise again.

 

[Bob Kensill]

I run a Mac 21 in an Eagle SG. Mac parabolic pipe set at 8". Octura 1445 cupped and 65% wildcat fuel. Break it in like you want it to run. Mine is three years old and all original.

 

[jaso]

Thanks All for the info, I just got back on here after being away for training for my work.

I'm running the std parabolic pipe on the recomendation that it's easier to get along with and keep a consistant setting. I might give the short pipe a try later on but first it's run in and get some more props to play with and worry about pipes later on. I've got an old x442 that I ran on the weekend to start run in on and I also have a 1445 to start with once I get a few more tanks of fuel through it.

 

[[email protected]]

anyone using a 640 prop?? I'm breaking in my MAC .21 O/B on a Magnum tunnel today.

 

[izitbrokeyet?]

I use one,

640 is an excellent prop for that motor

you might want to consider propping down for the break-in though.