Hello,
As some of you know, I've just rigged my caribbean cruiser up with a new water cooling kit as well as two new motors. I'm having a problemw here these motors are not going any where, they certainly spin the prop but once you put it into the water, the thing goes slower than a little nikko boat that runs on two double a's does. I bought the Johnson motors that another forum reviewed and said that they were faster than the t-maxx's. Does anyone have a clue why it is doing this? It was my first run doing the boat, and perhaps it is breaking in the motors? I need help quick because I'm supposed to sell this either tomorrow or tuesday.

Thanks for your help,
Joseph Blossom

Ok, First make sure your prop, or propshaft is not slipping, or binding.

Which Johnson motors did you get? With the internal fan or without it? What's the part #?

Are they wired correctly, running the same way?
Gears not too tight?

Type and partno. would be nice.

Regards, Jan.

They are the Johnson 550's non-fancooled, I'm really not sure what is wrong, Perhaps I'll test the boat with one motor and see how it goes. (I don't have the motor sleeves that had the part number on it because I could not fit my water cooling on over it.) But they say johnson on the front and back.

If you decide to test with one motor, make sure it's a short run, before something smokes....

The prop will be too big for one motor to handle.

IMHO standard 550 won't do in this configuration (too slow. too hot, short runtime).

Regards, Jan.

Well, I've figured out what is the problem, The ESC puts out 7.2v even though there are a total of 14.4 volts running into it, Since it is a mechanical one, I should be able to change it with out a huge hassle, I'll just have to figure out how to in the first place. The mabuchi motors only used 6 volts, and these use 14.4

Does anyone know how to go about changing a mechanical There are two switches where the batteries are connected.

These are in order as the connectors on each switch. So the top two on both of these are also the top two on the switches.

Switch one:
- Black from battery 2
- Black goes to other switch
- Black from battery 1, Black from motors (two wires hooked up to the same connector)

Switch Two:
- Red from battery 1
- Black to the other switch
- Red from battery 2, red from motors

I need to create 14.4 volts, not 7.2 volts

Could you make a diagram and post it?
And a pic of the switches?

I can't make heads or tails of it.

What functions does the switch provide?

Forward, stop and backward?
Stop, half throttle and full throttle forward and half throttle backward?

Regards, Jan.

Just forward I believe, I'm Pretty sure it is go or don't go. I'll get the diagram and pictures of the switches soon.

Hosemeyer,
I'm definitely not sure of what you're using, but by the description it sounds like the two switches are used to change the polarity of the current going to the motors (reverse). The only mechanical speed controlers Ive seen didn't have a voltage limiting function (but I'm NOT familiar with the one you are using). In general, only electronic speed controls do any voltage limiting (and like all general statements, there's always exceptions!).

The easiest, but not always the 'best', way to double the voltage of a supply is to double the number of batteries. Use two 7.2 packs in series. That'll also double the weight, so you see why it isn't always the 'best' way of doing things. The 'other' way around the problem is to find motors that use 6 or 7.2 volts. Also not the easiest thing to do...
- 'Doc

@LtDoc,

In the good old days when ESC's costed a fortune, there were servo-operated microswitches (robbe, among others) that allowed two packs to be wired parallel (=half throttle) and in series (full throttle).
Adding two more switches got you half throttle reverse.

Very crude, very abusive on both batteries and motor, but it worked.

I find it peculiar that in this day and age there are still manufacturers fobbing off their customers with switches....

Regards, Jan.

Well, Can you tell me how you'd wire batteries in a series? Isn't it one battery from the positive going to the negative, and so on?

Here is a diagram, the red is positive, black negative, the little silver slivers under neath the black are what hit the switch when the servo moves.

Hi,

What you've drawn is a series-parallel system, like I mentioned a few posts up.

You should measure (on the motor wires) 7,2V in one position and 14,4V in the other.

Are both switches depressed at the same time when the servo turns, or do they open/close, after each other.

And can you tell me wich connection is NO and wich one NC?

Regards, Jan.

Well, I've figured out what I'm going to do, and I assume it will work. First, make a wire harness, connect red with black, then the other black and red connect them to a connector, then hook it into one of the supplys to give it the full 14.4 volts. (because the speed control works with one battery plugged in)

I got it all fixed. It is going at a good 15.78 volts, which should be plenty for these motors. Thanks for the help! Before I sell it, I'm going to bring it to my lake to make sure it runs well, but I have no doubts now. (The lake is right accross the street.)

OK - How did it work out at the lake? Which Jognson motors did you get (PT#) and where and how much did you pay? Did they work ok or did they get really hot?

Well, The proformance could be better, So far, the original motors seemed to do better, It seems that the boat cannot get off of plane, but it was doing that before I replaced the motors so I'm trying to figure out what it could be other than per haps the trip tabs. I've considered taking them off, or adjusting them, but I'm not sure which way I should adjust them. When I ran them, with a 5 coil water cooling kit over both motors, they seemed to keep a reasonable temperature, I didn't notice any overheating of any sort. Tomorrow I'm going to mess around with the boat until hopefully I can get it off of plane.

Hosemeyer,
I would think that adjusting the trim tabs would certainly be a good option, if there was no noticable difference in performance with the new motors. (Since I've no 'hands on' experience with trim tabs, don't put much 'faith' in what I say about them!)
- 'Doc

It seems that megatech finally released their Hop up kit that was coming soon for the past 2-3 years, Perhaps I can get one for free and see how well it works.

Are the motors you replaced similar to the ones you bought new. The windings in the motor may be the big difference which is causing the speed reduction. you may need more voltage at this point if the new motors have more windings to see a better speed gain. Bigger motors isnt always neccesarilly fast. Other controlling factors are the internal windings of the motors. Larger motors are more torque but with a lot more windings it has less RPM. my Villain EX uses two Monster Max wilds which are 19 turn so i get more RPM then the stock Titan motors which i think are 23 turn.look at the pics on my webspage.

http://blackwidowsinj.tripod.com/MeBluEyz99