Hello, forgive me for asking a question that I’m sure this has gotten some discussion in the past. It seems like my web searches have turned up a variety of different opinions. Well, I’m hoping to get some advice from folks that have had real life experience running a similar motor than mine. I have a 71 Johnson 25hp and am curious what you people suggest I run for plugs. I replaced the ignition parts with Sierra coils, condensers and plugs. I had it tuned up over the winter before I started learning to tinker with it myself. At that time, the “mechanic” replaced the plugs with Champion j8C’s, changed the impeller and gear oil.
I recently read the service manual that states my motor calls for Champion J4J’s. I found them for sale online from OMC. Should I keep running the J8C’s or would the J4J’s run better. I have an electric trolling motor I use when trolling for trout and Bass angling. I plan to run the Johnson 25hp at WOT or close, to get to point A to B. I also plan to throw a smaller high speed jet in when trout fishing lakes above 6k feet to 7500’ elevation(local shops near those lakes have me advise on what size jet)
I’ll replace the smaller jet with the stock one when I’m back to my local lower lakes.
The motor was running great using the J8s when it was working. I have been working out some unrelated issues due to coil wires breaking due to bad wire placement and about to replace the upper crankshaft seal to fix a leaking seal I noticed when going through the magneto components. Looking forward to setting the timing once that’s done with my new timing tool.
thanks in advance for any suggestions on what plugs I should run.
Dave
I recently read the service manual that states my motor calls for Champion J4J’s. I found them for sale online from OMC. Should I keep running the J8C’s or would the J4J’s run better. I have an electric trolling motor I use when trolling for trout and Bass angling. I plan to run the Johnson 25hp at WOT or close, to get to point A to B. I also plan to throw a smaller high speed jet in when trout fishing lakes above 6k feet to 7500’ elevation(local shops near those lakes have me advise on what size jet)
I’ll replace the smaller jet with the stock one when I’m back to my local lower lakes.
The motor was running great using the J8s when it was working. I have been working out some unrelated issues due to coil wires breaking due to bad wire placement and about to replace the upper crankshaft seal to fix a leaking seal I noticed when going through the magneto components. Looking forward to setting the timing once that’s done with my new timing tool.
thanks in advance for any suggestions on what plugs I should run.
Dave
