Goofy homemade parts question

[artificialreef]

Hello again folks. I am working on dialing in my 1983 3.7/470 and think i have isolated my problem to the resistor wire from the electric choke to the coil. I bought the mercruiser resistor kit (i think about 25$)but was looking at it and i have a little bit of a background in electronics.
Question. the manual states the wire should read between 1.5 and 2 ohms. Couldnt i have just bought 10ft. of tinned purple marine wire (about 3$)and looped the ends through a 1.5 ohm resistor that costs about .25 cents and solderded and shrink wraped it and made my own for about 3.25$? Isnt a damn resistor a resistor or is this a special marine resistor?

Thanks... Just wondering.

 

[artificialreef]

Re: Goofy homemade parts question

Well, that didnt read correctly. I would cut it and splice the resistor into the wire. The way i typed it looks like i made a loop circuit but i hope you know what i meant.

 

[UncleWillie]

Re: Goofy homemade parts question

The Logic is sound but the execution has a fault.
There is a lot more engineering designed into that simple piece of wire than most people ever imagine.
You will need to consider the power in the circuit.

Let us assume the wire carries 4 amps and it is 1.75 ohms.
Ohms Law (I^2 x R = P) states the wire will dissipate 28 watts.
28 watts across 10 feet is less than 3 watts per foot. The wire gets warm, but you can still touch it.
It limits the current to 4 amps as the voltage drops to 5 volts.

You could change it to a 50 watt resistor. They aren't small or cheap and require a heat sink. (More $$$).
Now all 28 watts are dissipated in less than 3 inches and it will be smoking if it isn't bolted to the heat sink.
The resistive wire is Old School engineering that still has it's place. It is a cost effective solution.
Don't mess with success until you thoroughly understand the circuit.