What is the resistor for on this Crossfire 150R?

currycarts

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Trying to help my 15 yr old rewire this cart. New wiring harness doesn't seem to have a place for it. The resistor is a small rectangular ceramic, (I think), box with 1 end connected to the starter relay. Wire is broken, so I don't know where it goes to. It does have a fuse in the broken wire. I've looked at many wiring diagrams, and am now just confused. Help with this wiring project is much needed, as it's my first attempt at any wiring. After harness was put on, I could hear starter spinning, but it wasn't engaging. I don't think I have it right.
 

itsid

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well, how about you post a picture of the part in question?
"small rectangular" possibly "ceramic"... is just not precise enough to guarantee a good answer.

if it is a ceramic high power resistor (which indeed could be a small off-white caramic square crosssectioned bar)
it has a marking stating the resistance and power rating (4.7k 10W or alike)
and that could tell what it's meant for.

So yeah I'm sorry but :useless:

the only resistor I am aware of on some gy6 150cc engines is the auto-choke protection resistor
it is connected to the voltage regulator and the carburetor (green/purple wire on the carb side and black on the regulator side)
via spade connectors usually.. can't tell what value it has I'm afraid..
I have not seen any resistor on the starter relay yet.


'sid
 

currycarts

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well, how about you post a picture of the part in question?
"small rectangular" possibly "ceramic"... is just not precise enough to guarantee a good answer.

if it is a ceramic high power resistor (which indeed could be a small off-white caramic square crosssectioned bar)
it has a marking stating the resistance and power rating (4.7k 10W or alike)
and that could tell what it's meant for.

So yeah I'm sorry but :useless:

the only resistor I am aware of on some gy6 150cc engines is the auto-choke protection resistor
it is connected to the voltage regulator and the carburetor (green/purple wire on the carb side and black on the regulator side)
via spade connectors usually.. can't tell what value it has I'm afraid..
I have not seen any resistor on the starter relay yet.


'sid
I think you are correct. I will get a pic tomorrow when it's light out. Thank you!
 

itsid

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Ah yeah indeed a resistor..

should have a marking (I think 5 Ohm 5 Watt is the common size)

but yeah with those spade terminals I'm positive it's the auto choke resistor
see that green and yellow wrapped pair with the nice connector
I think that's coming from the carb, right? (colours would suggest so)
it's green is connected to end of the resistor, and the other end has to go to the regulator (a black wire)
it's yellow is connected to a red wire coming from the regulator
not directly however but via a mating connector with a purple and a red wire
the red mates with the yellow, and the purple with the green..
the purple then is in fact directly connected to the resistor.

(I think that stupid kart had such terrible twist on terminal caps for the black and red wires for some unknown reason...)

Anyhow..the yellow red has to be disconnected from the resistor for sure..
NOT WHERE IT BELONGS!

the yellow red is going from the regulator (directly yellow/red) to the starter relay
via a fuse .. nowhere else
that fuse however needs to be in a housing, (twistlock fuse I think... on cheaper occasions heat shrinked)
on the starter relay end of that fuse is another wire attached (red IIRC)
that in turn goes to the brake switch if my memory serves me and then back with another yellow/red wire to the starter relay
(oddly to the other relay terminal the one with the green/yellow wire, not mating with the yellow/red coming from the fuse!)


'sid
 

currycarts

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Thank you SO much! This is just how it was when I got it. I'm going to change things and see what happens. Can you take a look at this and see if it looks like a god diagram to follow? This is a Howhit 150cc with reverse...

One quick question..
If the new wiring harness has a plug for the carb, do we omit this resistor? That's the ONLY electrical component not included in the kit, and there are no wires off the harness FOR the resistor, that I can see.
Thanks!
 

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itsid

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yeah that diagram looks to be correct..
keep in mind that the wire colours might have changed over the course of model years without further notice,
so make sure to follow the wiring electrically to be sure colours match and if not note down the wire colouring
on a print out of said diagram. (for future reference and to not mess up by accident)
A simple multimeter with continuity check will do the trick just fine.

No, you should NOT ommit the resistor, it's an more a part of the carburetor not the wiring harness really.
Reason behind it is, that on some (actually MOST) carbs the coils have a fairly low resistance themselves,
(that way they can be somewhat adjusted by said resistor for different areas and average temperatures)
Powering such carb auto choke with an undampened voltage supply can cause the internal coils to burn out
and the carb will be permanently damaged
on some the auto choke isn't even easily replaceable and you're pretty much screwed.
that'S why on some karts the resistor is a 10Ohm 10Watt unit on some a 5Ohm 5Watt and on some there isn't a resistor at all.

So keep the resistor inline with the ground wire of it's powersupply, that way you can control the voltage drop
and thus keep the carb's auto choke function working.
Since it's to assume that it is meant to work with the carb you got.

The proper carb connector (as can be seen in the diagram)
is a simple length of twin wire with a connector on one end (shrink tubed).
it is NOT part of the wiring harness usually but seperate.
Some harnesses have a very similar -if not identical- connector like the Carter Bros or Hammerhead

So be sure to check all connectors twice!
NEVER make any connection with the battery installed much less the engine running.
Check that a connector is indeed the correct one for the plug you're about to attach
(by following it's wires around comparing that to the diagram while noting down the colour coding)
Never just assume a mating connector to be correct even IF the colours do match!

And (secodly) before finally re-installing the battery make sure there is no short
or missed connection
or loose wire that could touch the frame and short out whilst driving.

'sid
 

currycarts

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I appreciate your info. I seems my safest route is to do the wiring using the diagram exactly as it is. Can you tell me the wire size, by chance, that should be used?
 

itsid

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Sorry.. not really..

personally I tend to use 1.5mm² copper multi stranded wires quite a lot in repairs (that'd be -what- AWG15 ?)
that is usually good for ~15 Amps * and covers most cases without being too thick.

it also fits in most common connectors and thus gives me an easy time working with it.
It's usually overkill for sensors and even most "powered" things don't need anything near 15 amps
(@~13.5V from the regulator that's around 200Watts of power)
then again things like the starter motor or sets of incandecent lights,
most common ground wires and such need bigger wires still.
So it's a good idea to be aware of the powers being fed through.

In your case.. I'd take the same size as 'suggested' by the part you are connecting to whenever possible.
I'd say the carb uses a 1mm² wire [AWG17 ish] for example so I'd stick with that until it's combined with another wire.
that way you unlikely need to wedge a thick wire into a small connector and create an inadvertent short with a stray strand or such.

Some wires will be harder to judge like the CDI or the voltage regulator.. battery or fuses etc.
I usually dial in for the bigger size when in doubt there are very few cases where that could cause issues
(my ecu for example doesn't like a wire to change it's resistance so fixed length and gauge is required for all sensors to work properly)
but on a non fuel injected engine with nearly no sensors at all there is little chance of such things becoming important ;)

'sid

* note: I'm just eyeballing the max amps most of the time.. 10 amps per 1mm² is just so easy to remember..
AND it holds true for well insulated multistranded copper wires
some even exceed that value.. cheap wires doesn't come close but I avoid that at all costs anyways ;)
 
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