Continuity of spark plug wires 1999 Johnson 90 v4

[Rom6100]

I’ve been trying to figure out a misfire issue, bought new spark plug wires that I’m not sure might be the issue currently, I have 90hp Johnson with OIS, old wires read 500 ohms, new read 1700-2100 ohms. I replaced power pack and rectifier, Had a voltage issue, now resolved and power pack seemed to fix the misfire briefly. However I put the pack on same time I put new wires on. Not the OMC gray wires but a blue set off amazon. I’m hoping these are the issue. Motor ran better for a little bit then began misfiring again. I’m going to swap the gray omc back tomorrow. I’m new to the OIS system and read they need the gray wires. Any info on this? Thanks so much. Forgot to mention the coils checked ok with continuity of 295.

 

[GA_Boater]

Are the ones from Amazon radio suppression wires? The color of the wires have noting to do with it, wires come in a rainbow of colors. You should be using wire core (stranded) wires.

 

[Rom6100]

They don’t say anything about it so I’m assuming they are not. These are the ones I bought
https://www.amazon.com/gp/aw/d/B07HQ8YHF8?psc=1&ref=ppx_pop_mob_b_asin_title

 

[Chris1956]

500 ohms is correct, according to my service manual.

 

[racerone]

Are we 100% sure that wires on these optical system have the be ----WIRE CORE------Yes or no ???

 

[Chris1956]

I would expect wire core to have zero ohms resistance. The service manual calls for 500 ohms, but does not specify their composition.

 

[McGR]

OIS wires are definitely not solid core like on older OMCs. My understanding has always been that this system is very sensitive to various EMI/RFI interference. Proper plugs and wires are imperative. Are your wires from Amazon OK... hard to say for sure. Generally, I don't have problems using many aftermarket parts, but in my opinion OIS plug wires are one of the items where its best to use OEM.

 

[Rom6100]

So today i removed the amazon wires and out the OMC stock ones back on and not more misfires. Ran great. I replaced them at the same time I replaced the power pack and the rectifier. After those parts I was chasing my tail trying to figure out why the issue. I believe it was the resistance of the other wires causing a problem. Hopefully no more issues. Thanks all for the info on the wires. Good to know the resistance was the same as the manual.

 

[Faztbullet]

The spark plug wires need to be the gray inductive resistor wires - these are not automotive wires. Secondly, the spark plugs should be the factory recommended QL78YC. Use of other spark plugs or wires can cause problems inside the power pack from RFI and MFI noise. CDI Electronics has the spark plug wires available as a set P/N: 931-4921.