Optimax 115, 2007 - help needed - cutting off

[dawg11]

I have a 2007 Optimax 115, less than 300hrs. When cold, often cuts off when first put in gear. I think the idle may sound a little rough but it doesn't cut off until I put it in gear. I may have to restart 1, possibly 2 times and then it's fine. Runs good otherwise. I have replaced the plugs a month or two ago but did not check the gap (they are supposed to be pre-gapped .31 I thought?). The old plugs also did the cut off thing but it seems more regular now. There was a time however when I did not have this problem so I'm not sure if the plugs are involved or not. I will take them out, check gap, and re-install if it is worth doing. If the engine is cut off but still warm, I do not have this issue when restarting. I also don't think it cuts off when on muffs and I put it in gear but I can check further if that provides any clues. What is the likely cause? Thanks.

[JOE54]

check plugs for sure need to see what fuel and air psi are doing as well as sensors

[dawg11]

20200624_173214.jpg
Here are the plugs from a couple of months ago. So I need to get a feeler and confirm .031 or .032"? I notice plug 3 is all black. Does that mean anything? I did have coil #2 recently go out so have just now changed all coils.
On the fuel and air valves, can I use a tire gauge that does 150psi? I'm sure that's not by the book but will that suffice for a quick check? Just run it at idle and check those 2 valves?
When you say check the sensors -- what sensors/how?

Thanks.

[dawg11]

update: I found a wire gauge and could not fit .030" under the arm so I know they are not gapped right at .031 like I thought NGK said. I'll try to get it between .030 and .035 but can I still use the black plug 3? Could this cause the cut off I have been having as described in original post? Why is the plug different than the other two? The coil that went bad was the cylinder above (though I did replace all 3 just last week).

[JOE54]

wouldn't use plug,yes possible misfire ,did you use factory oem coils ?problem with flooding or spark problem on that cyl , sugest run cds scan on all switched and sensors at dealer level, and you may have bought a new bad coil chek spark on that cyl when mtr is cool

[dawg11]

I still have the plugs that came out before these so maybe I will use one of those until I know it won't get ruined again. I used aftermarket coils from eBay - there were hundreds sold with good feedback so I thought those would be ok. I did just swap all the coils but the plugs were done approx 2 months ago. I could put a factory old coil back but I don't really know if the old coil or the new coil is the potential problem. Can I use a spark tester (with light/spark window) and determine how good or bad the coil is? I assume #3 is working as when #2 went out, my motor wouldn't really run at all. Does the spark in the tester window need to have consistent, rapid flashes at equal intervals or not necessarily?

[JOE54]

consistant pattern ,may have rfi problem

[SilverFox579]

The correct gap is .032" - .033", check this topic and scroll down to plug recommendations, you'll find the 1.5L Optimax 3rd on the list.

Oil, Battery, Spark Plugs, Fuel and Fuel Additive Recommendations