Spark Plug Question

[i386]

Chrysler 20HP<br />Model: 202HD<br />S/N: 2143<br />1972<br /><br />Reading my parts manual I see the plug specs say use Champion L4J. When I got the motor it was running NGK BR6HS. To make a long story short... After cross referencing and reading plug mfg. specs., the plugs in my motor are itentical to the ones recommended except the heat range is a 6 instead of a 7. Again for clarity: The manual says use a 7 and I have a 6. My plugs are reading wet. Before I start tweaking the fuel and timing should I install the hotter plugs and take another reading to see where I'm at?

 

[eurolarva]

Re: Spark Plug Question

Most chysler users here are substituting L82C champion plugs for the L4J. NAPA says they are the closest cross reference plug. They cost about 2 bucks a piece. If you troll a lot use the L86C. They are the next hotter plug.<br /><br />When you run your motor you want to run slightly rich so your plugs will be a little wet. Maybe try doing a decarb on the motor and try switching to the L82C. See Frequently asked questions on how to decarb.

 

[rbruce63]

Re: Spark Plug Question

I wouldn't put NGK's in my Chrysler, some 4 stroke Mercury's have NGK spark plugs, but their powerheads where made by Yamaha a Japanese manufacturer. <br /><br />There are really no cross equivalent between spark plug manufacturers and each manufacturer employs a different heat range than the other one, and since your Chrysler came originally with L4J then the equivalent would be the L82C.<br /><br />The 20 HP is not a performance motor, having said that, I in my humble opinion wouldn't tinker with spark plug heat ranges nor timing as the consequences could be dire in the piston crowns. This is specially true for 2 stroke motors.

 

[i386]

Re: Spark Plug Question

Good deal. I'll get the L82C's and put them in. As far as tinkering goes, maybe I used the wrong term. Since I just got the motor and don't know what all has been done to it before I got it (like putting in the wrong plugs), I just want to make sure everything is set to spec. I havn't taken her very far up the river yet, and I won't until I feel good about the motor.

 

[rbruce63]

Re: Spark Plug Question

You could experiment with the timing a bit as the proceedure described in the manual opens for experimentation: "10 degrees from top of ramp on cam" that means to advance the timing 10 degrees from the point where the point will not open any further and where do you know is 10 degrees in the stator or cam?<br /><br />I would also in my humble opinion recommend you to make an online boater's ed course recommended by the US Coast Guard as it will put you aware of the risks and the consequences of NVH (noise, vibration and harshness) and may I add heat and dehidration.<br /><br />But please, do enyoy your motor as mine has never left me stranded (enough to call it that)!