Honda 20hp, no spark

[Russ Johnson 141]

Hey, OTP.. you say a trailer...enclosed or open? How big if enclosed, and is this engine on a hot water machine?

[Aplus 525]

This is a great thread! It should be oneday enshrined in the library.

(of course it doesn't hurt that I have the exact same skid as Alan.)

[One Tough Pressure 580]

You can also use a briggs fuel pump for a vanguard.

Now a problem that I had was it cutting out. I figured it was vapor locking, so I rerouted the fuel line up the right side, and put a hole in the side of the plastic to pass the line through. It is then a straight shot into the fuel pump.

Scott

If mine was vapor locking, why now and never before? One of the problems I found before I started this thread andafter I replaced the original fuel filter, was that the hose to the fuel pump from the filter was kinked due to the loop that it has to make and I pulled it to hard when getting the old filter off. It still ran but kinked hoses are never good. I ditched that Napa filter and use a racor, same as the burner has. No guessing ig there is any water in the tank now.

Hey, OTP.. you say a trailer...enclosed or open? How big if enclosed, and is this engine on a hot water machine?

Open trailer, hot water

[Scott Stone 604]

Because it is hotter now than it was before, and hopefully, your engine has more time on it that before, so that there might be less vacuum and the pump might not work as well. Mine ran fine for a year or so, and then as soon as it recently started warming up, it started vapor locking. I hav ehad it happen before with the same machine and a different engine.

Scott

[One Tough Pressure 580]

I replaced the fuel filter, and cut open the old one. It had some plastic chips in it from my water in the tank issue a short while back. I had bypassed the fuel filter for a brief moment when checking to see if that would help anything. When the water would not allow starting.

The fuel pomp did not make any changes so I am still searching for answers.

Most of my work is at night, so it is fairly cool. I am not sure that vapor lock is my issue, but you never know. Had major problems today, I lost spark on the right side many times. It would run great for a few minutes then bog on one cylinder, then flat out die. I am pissed, as I have changed many things and as soon as I think I get it fixed, it is something else.

Changed items in last few weeks

fuel filter

plugs

fuel pump

removed and inspected carb twice

removed and flushed gas tank twice

So the next item on the list I guess would be the magneto's. Not sure what they go for or how readily available they are. I also have a new carb solenoid on the way, just in case.

I guess if the oil sensor was flawed that it would cut spark to both plugs and not just one. I have checked the oil a gazillion times just to make sure it is correct and it is fine. Just changed it and oil filter, so I am confident that the filter is not clogged and causing issues.

My last ditch effort if this can not be resolved very quickly will be to ask the local shop to pull a new motor off a skid and replace the whole darn thing. I will then send the current one in to get fixed and have a back up. Afterall, you never know when you might need it.

[Washaway 64]

Call The Manufacturer!!

[PWkid 79]

Hey Alan,I kind of had the same problem on a new motor 23hp vanguard on my machine.My machine would run then it would bog down like it was running out of fuel.I checked fuel filter it was full.I took it to a vanguard service center they said It sounds like the little fuses from the magneto.Long story short I put them on and same thing turns out when they built my skid they pinched my low oil shutdown wire against the belt guard and it was rubbing and causing it to ground out.I finally found the problem, I don't trust to many people to work on my equipment.

[Russ Johnson 141]

A couple of more things to try. Check the gap between the mags and the flywheel. Should be .016" or .4mm. Do you or anyone you know own an electric meter that measures ohms of resistance? The spark plug caps have radio suppressors in them. The resistance through the cap should be 7.5-12.5 K ohms.

Let's keep trying with this, Alan. Hate to see you buy a new engine for a $50.00 part. Troubleshooting is SO much easier when the machine is in front of you. Drive it on out here to KY (lol).

[PLD 14]

The spark plug caps have radio suppressors in them.

Great feature. Now I don't have to worrk about hum when I'm sitting in it listening to AM radio. :)

[Russ Johnson 141]

Go to your room, doolittle.

[One Tough Pressure 580]

A couple of more things to try. Check the gap between the mags and the flywheel. Should be .016" or .4mm. Do you or anyone you know own an electric meter that measures ohms of resistance? The spark plug caps have radio suppressors in them. The resistance through the cap should be 7.5-12.5 K ohms.

Let's keep trying with this, Alan. Hate to see you buy a new engine for a $50.00 part. Troubleshooting is SO much easier when the machine is in front of you. Drive it on out here to KY (lol).

I checked for any pinched wires since I had the cover off a few times and none were found.

I replaced the right side magneto, and since I did not have any reference at the time, gapped it the same as the left side, which is.25mm

All was fine for the first 4 hours then the machine stalled many times in the last hour.

I have a meter so that will be my next task.

I have been told that if I disconnect the diode that goes to the magneto and it runs fine then that is my problem. If it runs fine without the diode then what purpose does it serve?

[Russ Johnson 141]

#7 is the shut down diode assembly. It makes the electricity flow from the coils to ground to shut off spark. There is a possibility that it could be bad. I'll check tomorrow and see if there are any test specs for it.

[One Tough Pressure 580]

I recognize number 7 as the diode, numbers 1 & 3 as the magnetos, but what is number 5?

It would be cheaper to buy a new engine and use it for parts, rather than buy individual parts. I have already bought half an engine with the cost of parts. Just figures.

[Russ Johnson 141]

#5, as well as #6 and #17 are the charging coils, depending on which system your engine has. They are under the flywheel.

[One Tough Pressure 580]

Charging as in battery charging or ? I have not gone under the flywheel as of yet, and I hope I do not have to.

I ran the machine another 3 hours last night and all was fine until the end, when it started to intermittent run rough and backfire on occasion.

It has yet to bog like it was but it still needs some fine tuning.

[Russ Johnson 141]

Yes, charging the battery. The number of coils determines the charging amperage.

I would say that your diode is not at fault, then. They don't get hot and break down. They burn out and don't come back.

You might try re-gapping the ignition coils, .25mm is a little tight.

[One Tough Pressure 580]

Regapping it is then. I will do that tomorrow morning, as it is maintenace day for me. I used the .25mm as that is what the untouched one was.

I have had no problems with the battery, so the coils are good for now.

[One Tough Pressure 580]

Time got a little tight and I did not have time to change anything, before I ran it again. All was fine and no dying, or back giring so for the moment it has cured itself. I will eventually dig into it again, but for now it runs well, so why tweak what is not broken.

[Don Phelps 85]

Because it could still be broken!

:lgbounces

Oh, the drama!!!

[beyoungsr 14]

OTP,

You might find some ideas below if the problem has not been resolved.

20 hp honda gx620 simpson unit it runs for apx 15 min then shuts off will start back up but shuts off after a few minutes anyone have ideas thanks steve steve

06-30-05 13:53:14PM

IP = 64.12.116.10

46132

RE: Honda 20hp trouble

is it a new unit. how long have you had it. was it sitting for a while. more details.

jjs

06-30-05 15:01:17PM

IP = 70.32.79.162

46135

RE: Honda 20hp trouble

check oil, it may have a low oil shutoff.

If thats ok take air filter out and see if it runs better then, if so replace with new one. dave

06-30-05 15:16:40PM

IP = 205.188.116.201

46137

RE: Honda 20hp trouble

Had a similar problem with a Simpson 5000 psi unit and it was the fuel pump.

william

06-30-05 17:12:52PM

IP = 24.211.112.96

46141

RE: Honda 20hp trouble

I have had 4 of them vapr lock on me. After I rerouted the fuel lines, no more problems. I have also had them do this after it had been too long between oil changes. The level was fine, but it still shut down. Probably because the oil was too thin after having way too many hours on it.

Scott Stone

06-30-05 19:40:11PM

IP = 68.98.110.110

46145

RE: Honda 20hp trouble

I just went thru this and one issue was a crimped/pinched fuel line. Honda for some reason had to make a sharp turn on the line where it comes off the filter and goes into the pump. Apparently it shrunk from the heat and pinched it was. It would run fine for awhile then die. Start back up and run fine for a little bit then die again.

Behind the plate that reads Honda 20Hp is the fuel pump, and the line that comes over the top and enters the right side was the culprit. 2 screws will release the plate for a quick check.

PP

06-30-05 20:38:53PM

IP = 68.169.178.97

46149

RE: RE: Honda 20hp trouble

I had the shut off problem for a while with my GX620. It was not as frequent, but it would go down for no reason and start back up with no problem.

Then one day it shut down and refused to re-start. Had it checked, they found a bad fuel solenoid. After that was replaced, never had a problem. Some guy named Frank

06-30-05 20:23:55PM

IP = 70.110.65.249

46148

[One Tough Pressure 580]

OTP,

You might find some ideas below if the problem has not been resolved.

RE: Honda 20hp trouble

I just went thru this and one issue was a crimped/pinched fuel line. Honda for some reason had to make a sharp turn on the line where it comes off the filter and goes into the pump. Apparently it shrunk from the heat and pinched it was. It would run fine for awhile then die. Start back up and run fine for a little bit then die again.

Behind the plate that reads Honda 20Hp is the fuel pump, and the line that comes over the top and enters the right side was the culprit. 2 screws will release the plate for a quick check.

PP

06-30-05 20:38:53PM

IP = 68.169.178.97

46149

Here is me and my problem solved for now. I have beefed up the line and put more slack in it. I may do what Scott did and run the line up the right side to eliminate the sharp bend of the hose and reduce heat that made it shrink. The original fuel line got hard and brittle so when I replaced the fuel filter, I replaced the line, but I guess it was cheap stuff, as it did not last long before shrinking.

Extra fuel line will be part of my [arts box incase I have another episode.

So the recent problems were a bad magneto, and a pinched fuel line. The magneto was easier to diagnose than the fuel line. The fuel pump had debris inside from my brief bypass of it. If my gas was gravity fed to the fuel pump, it may not have been a problem, but the tank is below the engine on this one.