I’m having a MAC attack

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JPriami

Active Member
Joined
Sep 12, 2005
Messages
40
I’m having a MAC attack

I was looking to buy a used or near new catamaran made by aeromarine or some other more reputable company. But I already have a 32” cat that’s 36” over all length that’s brand new made by a company that people seem to dislike. It’s the Proboat Thundercat 31. I got it last week and broke it in. It has the .32 dynamite marine engine in it. Well on break in I noticed that this thing is incredibly stable. So I feel it could handle a lot more speed maybe. Right now I’d say it’s running about 35MPH with a Prather 220 prop. I can’t turn a much larger prop because the engine doesn’t get up to RPM.

So I feel the engine is weak. So as a back up plan to not getting a different boat. I thought about just working with what I have here & upgrading the engine. I like what I see in the specs about the MAC engines. It started out with wanting the MAC .45 but the MAC .84 isn’t much more in price. I have a few questions though & hope that some of you could answer them if I decide to upgrade the boats engine.

1. Do you think the boat will handle a .45 or .84?

2.Will a .45 or .84 fit in this boat?

3. What cable collet should I get that will adapt the MAC.45 or the .84 to a 3/16 flex shaft?

4. What belt & starter system should I look at buying? I am new to belt starting all mine have been pull starts or tiger drives.

5. What exhaust pipe works best with the mAC .45 or the .84?

6. What type of fuel should I use for break in?

7. What type of plugs run best in these engines?

Now please keep in mind that I haven’t decided to do this for sure yet. I am still thinking of waiting to find a good used cat for the money as I am sure I will have around $600 or more tied up in just getting the engine & what all I need to get it in & running. It’s just a thought I am kicking around & use what I have.

Here is a picture of the inside hull of the Thundercat I already have for reference.

pic link
 
I would put a Mac 67 in it as I think the 84 , which I run in hydro's, is a monster for that boat . Put the 67 in it and gut the 3/16 cable and use 1/4 " cable with an X - 460 for starters and you will be blown away with the explosive power !! Good luck with her !
 
I’m having a MAC attack

I was looking to buy a used or near new catamaran made by aeromarine or some other more reputable company. But I already have a 32” cat that’s 36” over all length that’s brand new made by a company that people seem to dislike. It’s the Proboat Thundercat 31. I got it last week and broke it in. It has the .32 dynamite marine engine in it. Well on break in I noticed that this thing is incredibly stable. So I feel it could handle a lot more speed maybe. Right now I’d say it’s running about 35MPH with a Prather 220 prop. I can’t turn a much larger prop because the engine doesn’t get up to RPM.

So I feel the engine is weak. So as a back up plan to not getting a different boat. I thought about just working with what I have here & upgrading the engine. I like what I see in the specs about the MAC engines. It started out with wanting the MAC .45 but the MAC .84 isn’t much more in price. I have a few questions though & hope that some of you could answer them if I decide to upgrade the boats engine.

1. Do you think the boat will handle a .45 or .84?

2.Will a .45 or .84 fit in this boat?

3. What cable collet should I get that will adapt the MAC.45 or the .84 to a 3/16 flex shaft?

4. What belt & starter system should I look at buying? I am new to belt starting all mine have been pull starts or tiger drives.

5. What exhaust pipe works best with the mAC .45 or the .84?

6. What type of fuel should I use for break in?

7. What type of plugs run best in these engines?

Now please keep in mind that I haven’t decided to do this for sure yet. I am still thinking of waiting to find a good used cat for the money as I am sure I will have around $600 or more tied up in just getting the engine & what all I need to get it in & running. It’s just a thought I am kicking around & use what I have.

Here is a picture of the inside hull of the Thundercat I already have for reference.

pic link

Only Mac motors available are what the guys on this board are selling. New Macks are not available, nor does anyone know when they will be. Onece in a while someone will sell a new one. Keep checking the board or post a WTB. Good luck.

Bill
 
I run a sprint cat 36 inch with a picco 67 using a 1/4 shaft to 3/16 also running a x460 prop at around 60 mph i would go with the 45 engine.Reason being its shorter and wont use as much fuel.Not sure of your tank size but the 67 i have take 20 oz to finish a race.Plus your hardware isnt the best.
 
Honestly, that hull looks fairly light and at 32" a good .21 should get you to 50+ mph. Yes a good .21 will make much more power than THAT .32!

Unless you build a lower profile radio box, it will interfer with a rear exhaust engine.

If you use a crank induction .21 with 180 degree header it will be an almost "drop-in" refit.

We have the crank induction MAC .21's going for $275. It pushes our 32" mono to 50 mph.

This engine is converted from our MAC 21 Outboard which can be seen on the home page of cmdracing.com

Good boating,

Andy
 
Last edited by a moderator:
Thanks for all the tips & info. I was looking last night & all the places I seen the Macs I mentioned for sale are out of stock or on order etc. So boaterbill is right. I'll keep an eye out here for one. I think my tank holds is it 250ml? It takes all of my little fuel filler bottle to fill it. But looking at the tank in the boat it has 12oz stamped on it. Guess that isn’t much when feeding a larger beast.
 
Thanks for all the tips & info. I was looking last night & all the places I seen the Macs I mentioned for sale are out of stock or on order etc. So boaterbill is right. I'll keep an eye out here for one. I think my tank holds is it 250ml? It takes all of my little fuel filler bottle to fill it. But looking at the tank in the boat it has 12oz stamped on it. Guess that isn’t much when feeding a larger beast.
12 oz will run a 21 for a LONG time.
 
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