Practical joke damage to Honda 20 HP ignition coil ?

duffdav · September 30, 2006, 12:52:44 PM

Anybody have any idea if running a Honda 20 HP with a plug wire unhooked on one side could damage the ignition coil ? The first thing Friday morning my man running my Norwood complained of no power. It had run fine the previous day. A quick check revealed the plug wire on one side "'had come off ". Apparently one of the other guys playing a joke had took it off as he said they were giggling when he started up.

I put it back on but it still wouldn't run right on that side. The plug looked sooty black so I assumed maybe it had deadened it by not firing under a load of raw gas.... I've heard that can kill a plug. A new plug didn't help. That side seems to fire a little but won't burn the plug clean white. I can switch sides with the plugs...the other cylinder will burn it clean white.
Could maybe by not completing the ground damage the ignition coil by making it trying to complete a circuit elsewhere when the other side is pushing it ? The coils on the Honda are apparently weak. I've replaced the other side twice in the last two years. Them times though I was able to continue to saw on just on cylinder. Now I can't hardly get enough power to turn the blade....it pops, blows and backfires.

It is costing me $100 to have a coil sent air freight for Monday. I wonder if that will even solve the problem as it does appear to fire some but runs atrociously. If not any other ideas on where to look ?

I am going to chew somebody's butt at least a little come Monday if anyone will fess up if their joke caused the problem. It costs me a days production as well. Kind of like the time when a friend with coal trucks rebuilt a whole Mack engine when someone pulled the old tube of grease in the exhaust pipe trick.

Tom · September 30, 2006, 01:01:05 PM

Duffday,
I don't think the coil would be hurt by pulling the wire off of the plug. Sometimes we don't look for the obvious. If the plug is good (will fire on another cylinder) then move the spark plug wire to that other cylinder. It might be that you lost contact inside of the end of the wire where the plug seats when the wire was pulled off of the plug. Sometimes, if you pull on the wire rather than the fitting, the wire will slip back into the rubber fitting.

Moving the wire to the other side might let you know if the wire is damaged. Spark plugs wires do break.

JCam · September 30, 2006, 02:07:40 PM

Welcome to the Forestry Forum.
Hope a new wire fixes your engine.

den · September 30, 2006, 03:06:19 PM

I can't say for Honda, but some engines it will kill the module or coil.
Any real Mechanic will tell you never pull a wire off of a plug to check for spark.
Rember it will jump some were. Use a spark plug and lay it some were it will ground or use a tester (their cheap)and plug one end to the plug wire and ground the other end.
Dennis

Modat22 · September 30, 2006, 09:24:26 PM

it will only hurt the coil of module of it was shorting to ground. Generally the spark won't jump thru the insulation over the plug connector so it shouldn't have shorted.

Like Tom said check and make sure the wire is still in contact with the connector inside the insulator boot. Make sure the cylinder isn't flooded and the spark plug fouled.

Good luck

JimBuis · October 01, 2006, 06:11:47 AM

You might try to find out on Monday whether or not something else was done to it such as pouring water in the gas tank. Reminds me of somebody who pulled a gag on my Mom 30 some years ago by criss-crossing the sparkplug wires on our car. The car popped and backfired and wouldn't hardly run. She sold the car and bought another one. The guy who bought the car told us later that all he had to do was straighten the wires out and it ran perfectly.

Whoever was cutesie with your mill may have decided being cutesie twice would be twice as cute.

Jim

willknot · October 01, 2006, 08:37:08 PM

Hi, you might want to do a compression check. I had a similar problem with a twin kohler, The engine started running on one so I checked and the coil case had cracked allowing the wire to pop out a bit. I changed to coil , still ran on one , changed again still one. Did a compression check and there was none on the one side, a hole was burnt thru the piston. I was talking to a mechanic and said what a coincedence burning a hole in the piston and cracking a coil at the same time. He told me the coil caused the hole in the piston by having the spark jump caused it to be hotter and retarded. Other mechanics have also agreed. Might be worth checking. Good luck and welcome to the forum. ???

Will

tomboysawyer · October 02, 2006, 12:06:36 PM

Gotta love employees.

If you do get the thing fixed, be sure to change that oil. Must be fulla gasoline by now.

jack · October 02, 2006, 05:12:20 PM

Garwsh, could you get the employee joker to confess? maybe touchin him to that coil wire to CHECK the GROUND.....might do the trick.?
I had a honda engine that stopped workin........checked everything that i thot was obvious, then after breaking a 100.00 bill on stuff...... Some guy comes up to my bench yakin and points to a slit in the spark plug wire.......it was viberating against the cowling, cut thru enought to ground it out.

live and learn.
JAck

duffdav · October 02, 2006, 09:56:27 PM

My ignition new coil came today. Installed it. Still the same spudder and miss problem. I checked the valve clearance. OK at .006 and .010. A compression check give 120 psi. I put a timing light on the plug wire. A flash now and then. Ignition still appears to be the problem. I traced the wire that goes to the ignition coil back to a little black box beside the switch...a wire to each coil and one to the switch harness. I made a jumper wire with spade connecters to reach over the engine to the swap connecters with the other coils. That put the fix on it.

Plano Equipments Webpage http://www.planopower.com/store/honda/gx620qxa.shtml calls it an engine stop diode. The incomplete circuit must have backfed the high voltage charge and damaged it.

>>Gotta love employees.

Right. Their trick will cost me $150+ in parts. A big part of two days of my time trying figure out the problem. A 120 mile round trip to another part of the state Wed. to pick up the diode module and 5 days lost production...well over a $1000 setback. Plus my market was about out of the 10x14 wedges I was going to saw that they bundle with their high value yellow-poplar mining posts. The last time they had to get them from a bigger producer they brought in 12,000 which flooded the market for three months.

>>If you do get the thing fixed, be sure to change that oil. Must be fulla gasoline by now.

Yes. I had better do that. When the coil went out on the other side I ran it for about three weeks before I determined the problem. I wonder if the unburned gas may have washed down the cylinder. I took a compression check as a comparison on it today...it was only 100 psi. The engine doesn't have the power that it originally did 5 years ago...though it's still more powerful that the 23HP Briggs on my Hudson Oscar 36. Used to be you couldn't drag it down even with a dull blade which it will now.

Fla._Deadheader · October 02, 2006, 10:05:00 PM

Sounds to me like a serious decision needs to be made regarding SOME of the helpers :

:

DanG · October 02, 2006, 11:04:39 PM

I imagine this has already happened, but if not, a real serious "prayer meeting" about practical joking around a sawmill is in order! >:(

Fla._Deadheader · October 03, 2006, 07:33:43 AM

I was thinkin about dividing up the damages amongst the helpers, except for the Sawyer. He shoulda knew better than saw with a bad sounding engine. :

:

highpockets · October 03, 2006, 07:49:15 AM

Duffdav,
My ignition new coil came today. Installed it. Still the same spudder and miss problem. I checked the valve clearance. OK at .006 and .010. A compression check give 120 psi. I put a timing light on the plug wire. A flash now and then. Ignition still appears to be the problem. I traced the wire that goes to the ignition coil back to a little black box beside the switch...a wire to each coil and one to the switch harness.I made a jumper wire with spade connecters to reach over the engine to the swap connecters with the other coils. That put the fix on it.

I was reading your comments and can understand the frustration. I fought this similiar problem last year with a 20 h.p. Honda. I bought one coil thinking it was bad. Nothing improved. I lowered the coil to 0.008" as per a Honda dealers recommendation. Nothing seemed to improve. Finally I tore the carburator down for the fourth time and got into the little high speed jets. Boy they are small. Anyway, this seemed to make things better after two months of jacking with this engine.

I am trying to understand your comments here about swapping the wires on the diodes. Are you saying that you did this swap and found that the other coil then failed, or everything was ok and you did not buy a new diode box?. I looked at my diodes (with a v.o.m.) when I was having what I thought was coil problems and they looked good. I disconnected them and saw no difference.

What I have found is that although my engine will start and run very well, after about an hour or hard work, it will start missing and blowing smoke under load. If I back off the load, it will clear up. I have about come to the conclusion that I am having some valve stems sticking.

This engine is new on a saw I built some six years ago. The guy left it in the weather and I have had a lot of problems with fuel, water, etc. Any follow up you have would be appreciated. I am 61 and have been building engines since the 265 chev but this one is eating my lunch.

Tom · October 03, 2006, 10:17:36 AM

:D There was a day when we would just put some Marvel Mystery Oil in the gas to clean the engine. Things sure were simpler then. :-\ :D

ely · October 03, 2006, 10:17:07 PM

high pockets, this may not apply to your situa. but i will throw it out there anyhow. a fella told me the other day that if your four stroke engine does not run an oil filter then you should run non-detergent oil in it. otherwise it will get build-up on the valve stems and cause them to stick.

sawguy21 · October 03, 2006, 10:44:13 PM

Actually, a non detergent oil will cause the problem, not cure it. The detergents break down the combustion byproducts and allow them to be flushed when the oil is changed. Non detergents work for air compressor or pressure washer pumps where these byproducts do't exist but foaming would be an issue. Also, the detergents that get into the air supply are hard on air tool o-rings, not to mention paint jobs.

submarinesailor · October 04, 2006, 07:26:26 AM

I agree with Sawguy on this. The detergents in oil are designed to suspend particles until they are removed, ether by changing the oil or by a filter.

Bruce

highpockets · October 04, 2006, 07:46:18 PM

I really think this engine has sat up for some four year and needs running. It probably hasn't gotten 50 hours since new.

ely · October 04, 2006, 10:35:41 PM

ok maybe i was drunk that day and heard him in reverse. or he was drunk and spoke in reverse. :D

duffdav · October 05, 2006, 11:17:19 PM

>>I am trying to understand your comments here about swapping the wires on the diodes. Are you saying that you did this swap and found that the other coil then failed, or everything was ok and you did not buy a new diode box?. I looked at my diodes (with a v.o.m.) when I was having what I thought was coil problems and they looked good. I disconnected them and saw no difference. >>

I robbed the connecter going to the problem free side thus disabling that cylinder while correcting the problem side. Your question got me wondering if both sides could share the same connection and maybe I could make a temporarily fix while I await a new diode box which I did order. I made a wire that y'd off from the good outlet wire from the diode box splitting the connection to each coil. Didn't work. Neither cylinder would fire. When I unhooked either coil the opposite side would run fine.

They apparently were short circuiting each other. The purpose of a diode being to limit electricity flow to one direction, this must be the function of the diode box to enable them to share a common wire to the switch harness.

The new diode box came today and I am now firing on both cylinders though another day was lost as the Honda warehouse showed one in stock. The order arrived to the West Virginia dealer only to have it zeroed out...frustrating. Plano Equip. was able to get me one from Texas to West Virginia in 20 hours.

>>What I have found is that although my engine will start and run very well, after about an hour or hard work, it will start missing and blowing smoke under load. If I back off the load, it will clear up. I have about come to the conclusion that I am having some valve stems sticking. >>

The first time my coil went bad it would run maybe up to five minutes then give out when it got hot. Cool off and run OK for a little while. It would clear quit all at once though. Stuck valves would seem to be the most probable cause of your problem.

highpockets · October 06, 2006, 05:58:14 AM

Thanks for the reply. I guess a fellow could use a relay with two sets of contacts instead of the diode box but that is a lot of trouble. The bunch at Plano Equiment have a good wabpage. I had looked at them once as my Honda Dealer in Shreveport is not very helpfull other than relieving the weight of my back pocket.