395xp Hard Start, Tuning Issues - Bad Coil?

[gvsu141]

Just a thought, but did you gap the new plugs? Not sure if it's possible for a plug to spark cold and not hot, but wouldn't surprise me. Didn't see you mention you gapped the new plugs so the thought crossed my mind. I would think it really unlikely that two brand new plugs were bad out of the box, but I suppose it could happen.

Just ran out to the garage and checked them, one was at .022, and the other at .023. A tad large, but not enough to cause any issues.

When warm, there was ZERO spark. I have never heard of a gap of .022 causing zero spark. I'm running the 359 later today or tomorrow, i'll swap it out to see.

 

[Campin' Cutter]

Just ran out to the garage and checked them, one was at .022, and the other at .023. A tad large, but not enough to cause any issues.

When warm, there was ZERO spark. I have never heard of a gap of .022 causing zero spark. I'm running the 359 later today or tomorrow, i'll swap it out to see.

Yeah that gap size shouldn't cause issues. Oh well it was worth checking!

 

[sean donato]

There have been plenty of times I've had plugs bad out of the box. We used to get them in foam flats. Think there was 20 something in one flat. We would go through them till we found the right ones to degree them to a race engine. Every once and while we would get a flat with a couple of junkers out of the pack. Wouldn't spark, or had a cylinder drop out once the engine got to temp. Champion was notorious for this. Autolite and ngk not so much. Have had tons of issues with no name spark plugs people get off the internet. Best one was a push mower. Started and ran fine till you tried to mow with it. Stall right out in the grass. New plug and it worked like a champ. Just because it's new doesn't mean it's good.

 

[husqvfixit]

There have been plenty of times I've had plugs bad out of the box. We used to get them in foam flats. Think there was 20 something in one flat. We would go through them till we found the right ones to degree them to a race engine. Every once and while we would get a flat with a couple of junkers out of the pack. Wouldn't spark, or had a cylinder drop out once the engine got to temp. Champion was notorious for this. Autolite and ngk not so much. Have had tons of issues with no name spark plugs people get off the internet. Best one was a push mower. Started and ran fine till you tried to mow with it. Stall right out in the grass. New plug and it worked like a champ. Just because it's new doesn't mean it's good.

Interesting. What trade are you in?

 

[sean donato]

Mechanic, heavy duty diesel specifically, just recently changed carrier path to a ride mechanic. Nit as hard on the body. my uncle raced dirt modified, and my dad raced unlimited offshore 1/4 mile. Some outboard engines require the plugs be indexed so you go through quite a few till you find the right ones. Same for chasing peak engine performance, Indexing the plugs is worth a few extra hp. Every bit helps when your racing a spec class. For example for new junk parts, we had a dodge mini van in. Ecm was bad, went through 3 new ones till we got one that worked the dealer couldn't explain why we got 2 bad ones before we got one that worked. Few moths ago mercury 5.7l i/o had a bad fuel pump, new replacement fuel pump wouldn't maintain the required fuel pressure, replaced with another new fuel pump problem solved. These are rarities but it happens often enough that you need to be aware that it does happen.

 

[husqvfixit]

Sounds like fun!

 

[sean donato]

Yeah was a blast wile it lasted... 2008 kinda killed both off for us. Good times had bay all.