Conquest carb jetting

[bluebruin]

I inspected the spark plug cables, I cannot find anything wrong with them, front or back.

I found and read all this info:

TROUBLESHOOTING IGNITION SYSTEMS | smallengineinformation.com

How To Test & Fix Ignition System Problems | Briggs FAQ

Kawasaki FB460V 12.5 hp Won't Start Weak Spark

Some good info about fouling

https://jdagccc.custhelp.com/app/answers/detail/a_id/518/~/spark-plug-fouling-%28gator%29

I decided I want to test the ignition coil on the rear cylinder. I can't find the kawasaki hand tester for sale, and on a forum someone mentioned its $138 if you can find it. I read on another forum, you can use an ANALOG multimeter on the coils just fine. I ordered an analog multimeter on amazon for $20. So I'll use that to test according to page 122 in the FD620D manual. I can test the front coil to see if my multimeter is giving accurate readings, since it seems like that one is working fine. I'm hoping a bad coil could be the cause, it seems that most other possibilities are much more expensive fixes.

[PaSean]

It may save you some time and ag if you get the service manual and follow the diag procedures for the ignition system. Here is a webpage that has it in PDF format. Just scroll through the list until you see the link for your engine and d/load it. I recently found this and it may help you out.

"K&T Parts House Lawn Mower Parts and Chain Saw & Trimmer Parts"

[bluebruin]

It may save you some time and ag if you get the service manual and follow the diag procedures for the ignition system. Here is a webpage that has it in PDF format. Just scroll through the list until you see the link for your engine and d/load it. I recently found this and it may help you out.

"K&T Parts House Lawn Mower Parts and Chain Saw & Trimmer Parts"

thanks yes, I have that manual. That's the one that gives the specs for the readings on the coil on page 122 that I mentioned above. The diagnostics on the other parts of the ignition system seem more complicated (and require the use of the special kawasaki hand meter" lest you damage your motor..according to the manual) so I am hoping for bad coil.

[PaSean]

I don't think you'd damage anything by using pretty much any high impedance analog multi-meter as long as the meter runs off a 9v battery or smaller and it's not a Megger brand. Some of the auto schools I went to said use a meter that operates off of a battery voltage lower than the vehicle power supply voltage and avoid Megger products. I have a Snap-On DVOM that I used for everything but I have a $10.00 Harbor Freight analog meter that I've used allot when I want to see the needle sweep. Maybe someone else here can verify this.

[bluebruin]

I don't think you'd damage anything by using pretty much any high impedance analog multi-meter as long as the meter runs off a 9v battery or smaller and it's not a Megger brand. Some of the auto schools I went to said use a meter that operates off of a battery voltage lower than the vehicle power supply voltage and avoid Megger products. I have a Snap-On DVOM that I used for everything but I have a $10.00 Harbor Freight analog meter that I've used allot when I want to see the needle sweep. Maybe someone else here can verify this.

yeah, i came to the same conclusion so I purchased an analog meter on amazon that runs on a 1.5V battery. I got alligator leads so I can hopefully test it in place. The manual says to unbolt the coil but it looks hard to get tools back there

[Old Tucker]

I forget now what year it was that they changed the head and pistons on the FD620Ds. but the older style took the shorter plugs and the newer engines took a longer plug. On my FD620D when I bought it. The thing was a dog to put it mildly. I did some checking And found they had put the shorter plugs in her. Once I had the right plugs in she was a new engine. But be careful if you put the longer plug in the older engines you will have big repair bill. I thought it around 2000 that they changed the heads and pistons. Check your sin#
But that I do not think, that sounds like your problem. Its sounding more like coil. They can work just fine cold but once they warm up they can give you a weak spark. But then again it could be a number of things.
I also was running the argo 18 inch plastic track but since I switched to the Channel track I found the argo a lot easer to turn. It does not matter if you are on a side hill or in a rut she now turns on a dime. The plastic tracks are now working hard holding up a fence in the back yard

[JohnF]

Caution; You may experience a good tingle if the wire is bad.

LOL My original response mentioned this along the lines of- Now go put on your man panties and reach down in there and jiggle that wire. Also gave a story of a family member showing me which cylinder on a truck wasn't firing by grabbing the wire and watching the spark from his belly to the fender. He could also just grab and hold onto an electric fence (which sucks if you don't know that about him).

If you felt a good jolt (try the other one to compare ) then it would seem the coil is working.

[bluebruin]

received my new analog tester. I am really bummed. both coils check out exactly within specs. I have no idea what the problem is now. What else can cause weak spark?

[ARGOJIM]

If you believe this is the main problem, start it in the dark with the hood off and look for the light show when it acts up, if you see sparks either wire or plug is bad.
If you haven't cleaned the 2 small connections at the wire harness do that after it acts up, change?.

[JohnF]

...What else can cause weak spark?

Forget to get a gift for her birthday. That's a spark killer right there...

Uhm, sorry, sidetracked a bit.

Could be any of FD620ign.jpg

So, you put new plugs in, and you could again, so that we could eliminate broken plugs.
You tested the ignition coils and they test okay.
We don't know about the plug wire - it could be broken.
The way the ignition works the coils will not fire the plugs unless the igniter tells them to. That happens through the W and BY wires on the diagram. If those wires are broken or the connector to the igniter for those wires has corroded enough to open those circuits then the coils won't fire.
We don't know if the igniter is good.
The igniter uses the pulser to time the ignition. I think you said cylinder 2 so pulser coil 2 or the WL or P wire from it or the connector at the igniter.
Also, if the spark is weak, you could have a bad magnet (although it would be weak for both cylinders) or the airspace for an ignition coil way off.

Jim mentioned that it's usually a connector that has corroded or gone wonky. I assume that's what happened to mine because when I was trying to diagnose mine I must have wiggled something just right and it didn't fail again in over 2 years.

It can't hurt to pull each connector, clean them up, add a little dielectric grease on reinstall and see if this fixes it.

[bluebruin]

If you believe this is the main problem, start it in the dark with the hood off and look for the light show when it acts up, if you see sparks either wire or plug is bad.
If you haven't cleaned the 2 small connections at the wire harness do that after it acts up, change?.

the problem is that it doesn't "act up". It just runs on one cylinder all the time. I have only had it run on 2 cylinders 3 times now. Once at my cabin for about 60 seconds, once at home for about 20 seconds, and then after I changed spark plugs it ran for 15 minutes full power. If I go out there right now and start it up, it will be running on once cylinder.

I will have to check all the connections. Doesn't the igniter run both coils? So if it was bad, wouldn't both coils stop working, or be weak? anyway, I'll do as John suggests, try to check and clean any and all connections. I have a new second set of plugs that just came (the BMR2A's this time) that I can try.

[PaSean]

One of these will help determine if you have no spark or weak spark - Kmart.com

[bluebruin]

thanks. I ordered one on amazon for $6 including shipping, worth a shot. what does it do exactly?

[PaSean]

Hook the plug end to your spark plug (plug side) wire and clamp the other end to a good ground. Start or crank the engine and watch the end of the tester. If you have spark it will arc, you'll see and hear it. If it's good spark, it should be blue. If nothing happens, you have no spark at all to that particular cylinder, if it's weak spark it is usually orange and weak sounding as far as the "snap" goes. Try both cylinders so you have something to compare good spark to.

[bluebruin]

well, I found a good deal on a coil pack on ebay for $12 plus $6 shipping, so I went for it. was from a john deere machine with the same engine. Just came last night, and I tested it with my analog meter. Same exact ohm readings as the ones in my engine, and within the specs in the engine manual. So, I wen out to the argo, pulled the plugs the old coil pack and left it in place. Reconnected to the new one just loose in the engine. Started up like a champ. Let it idle for a minute. Then pulled the plug wire off the spark plug, and right away I could see the sparks jumping the gap, the same as I had observed previously on my front plug. Plugged the spark plug back in and took it for a spin. Bingo! everything is as it should be. runs like a champ. I don't think my spark plugs were ever bad in the first place, its just this coil pack was supplying weak spark to probably no spark at times. Its supposed to snow 10-20 inches tomorrow so I'll run it hard for 15-20 minutes again and see how it performs. cross my fingers, this seems like the fix.

its VERY strange that I tested all three coil packs and all three test out perfectly according to the ohm specifications in the manual. I just had a feeling, and a hope, that this might be what was wrong.

if I can get it to run consistently over the next couple weeks, I'll bolt the new ignition coil in place and bring the argo back to the cabin for a high altitude test. If that works, time to move back onto my hardtop build. Thanks for all your help and suggestions in leading me to this point.