danl1950

[danl1950]

Hello,I have a Honda GX620 that has very,very little spark at the plug.I took the machine(board edger)to a small engine mechanic and he told me that both coils were bad so I bought 2 new coils,installed them and shazam,I've got the same problem.I've unpluged the kill wires and nothing changes.Anyone have any suggestions for this shade-tree mechanic?

 

[briggs]

Hello,I have a Honda GX620 that has very,very little spark at the plug.I took the machine(board edger)to a small engine mechanic and he told me that both coils were bad so I bought 2 new coils,installed them and shazam,I've got the same problem.I've unpluged the kill wires and nothing changes.Anyone have any suggestions for this shade-tree mechanic?

how dose the magnet on flywheel look is it rusty if so clean it up with some steel wool is the plug new

 

[robert@honda]

There were a few Service Bulletins for the GX620, and some may or may not apply, depending on the serial number.

1. Air Gap: The ignition coil air gap to the flywheel must be set correctly, 0.4+/-0.2 mm (0.016 +/- 0.008 in.) Loosen the coil, place a long, flexible gap/feeler gauge (set to the proper thickness) under the coil, press and hold it against the flywheel, tighten bolts, remove gauge.

2. Spark Plugs: If run at low speed or under light loads, the original spark plugs may foul, or the engine oil may become fuel-diluted. First, be sure to check the oil level with the dipstick. Next, a hotter plug may help: NGK BPR2E2.

3. Later GX620's (serial 2007986?017570) had some failed rivets holding the decompression parts to separate from the camshaft. A new camshaft with improved rivets may be required. Only engines within the range are affected.

4. Later GX620's (serial 2000000?037853) may have cylinder #2 exhaust valve lifter issues. You can remove the valve cover, manually rotate the engine, and confirm if the exhaust valve is working. An improved lifter assy. is available if the old one has failed.

FYI, OTHER model Honda V-twin engines had an Emissions Recall for the ignition coils, but the GX620 WAS NOT part of this project.

If you'd like copies of these bulletins, drop me a PM with your email. If you are taking the engine back to the shop (and they are a Honda dealer) tell them to check Engine Service Bulletins #15, #19, #27, and #29.

 

[danl1950]

how dose the magnet on flywheel look is it rusty if so clean it up with some steel wool is the plug new

Hello briggs,yes the magnet was kinda rusty,cleaned it with emery cloth but didn't help.Thanks for your support.

 

[danl1950]

There were a few Service Bulletins for the GX620, and some may or may not apply, depending on the serial number.

1. Air Gap: The ignition coil air gap to the flywheel must be set correctly, 0.4+/-0.2 mm (0.016 +/- 0.008 in.) Loosen the coil, place a long, flexible gap/feeler gauge (set to the proper thickness) under the coil, press and hold it against the flywheel, tighten bolts, remove gauge.

2. Spark Plugs: If run at low speed or under light loads, the original spark plugs may foul, or the engine oil may become fuel-diluted. First, be sure to check the oil level with the dipstick. Next, a hotter plug may help: NGK BPR2E2.

3. Later GX620's (serial 2007986?017570) had some failed rivets holding the decompression parts to separate from the camshaft. A new camshaft with improved rivets may be required. Only engines within the range are affected.

4. Later GX620's (serial 2000000?037853) may have cylinder #2 exhaust valve lifter issues. You can remove the valve cover, manually rotate the engine, and confirm if the exhaust valve is working. An improved lifter assy. is available if the old one has failed.

FYI, OTHER model Honda V-twin engines had an Emissions Recall for the ignition coils, but the GX620 WAS NOT part of this project.

If you'd like copies of these bulletins, drop me a PM with your email. If you are taking the engine back to the shop (and they are a Honda dealer) tell them to check Engine Service Bulletins #15, #19, #27, and #29.

Good morning,thanks for the air gap info.I don't have a manual for this engine and have been unable to find that measurement.Broke a plug so I'm headed to town for 2 new ones and to see if I can find someone to check these coils,both old and new.I have a multi-tester and both sets of coils have the same ohm reading.Maybe I'm not using the tester correctly,I'm not very street-wise when it comes to electricity.Thank you for all the info.

 

[robert@honda]

Good morning,thanks for the air gap info.I don't have a manual for this engine and have been unable to find that measurement.Broke a plug so I'm headed to town for 2 new ones and to see if I can find someone to check these coils,both old and new.I have a multi-tester and both sets of coils have the same ohm reading.Maybe I'm not using the tester correctly,I'm not very street-wise when it comes to electricity.Thank you for all the info.

Try the hotter plugs suggested by Honda: NGK BPR2E2.

Here are the coil resistance measurements; note the Primary is in ohms, Secondary is in Kohms.

 

[danl1950]

Try the hotter plugs suggested by Honda: NGK BPR2E2.

Here are the coil resistance measurements; note the Primary is in ohms, Secondary is in Kohms.

I checked the ohm readings on the coils(old and new)and this is what I got.The old coils secondary,18.60 and 17.40,old coils primary 1.3 and 1.1.New coils secondary 18.49 and 18.71,new coils primary 1.5 on each coil.I wasn't sure that I was using the meter correctly because the readings I got weren't in the range you gave me so I contacted an electrician friend of mine and he assured me that the readings I got were correct.The readings I got were much higher on the secondary side of the coil,could it be that the new coils are bad also?I was asked today if there was some kind of module under the flywheel and I couldn't answer that because I haven't taken the flywheel off.Is there a module underneath the flywheel that's faulty causing these coils not to fire?If I unplug the kill wire and spin the engine over,the coils should fire,right?Hope I'm not being too much a bother to you,I just want to get this thing figured out.Thanks

 

[robert@honda]

I checked the ohm readings on the coils(old and new)and this is what I got.The old coils secondary,18.60 and 17.40,old coils primary 1.3 and 1.1.New coils secondary 18.49 and 18.71,new coils primary 1.5 on each coil.I wasn't sure that I was using the meter correctly because the readings I got weren't in the range you gave me so I contacted an electrician friend of mine and he assured me that the readings I got were correct.The readings I got were much higher on the secondary side of the coil,could it be that the new coils are bad also?I was asked today if there was some kind of module under the flywheel and I couldn't answer that because I haven't taken the flywheel off.Is there a module underneath the flywheel that's faulty causing these coils not to fire?If I unplug the kill wire and spin the engine over,the coils should fire,right?Hope I'm not being too much a bother to you,I just want to get this thing figured out.Thanks

Unlikely brand new coils are bad.

Keep in mind, the secondary measurement is in K-ohms, which is thousands-of-ohms. Check the scale selection or range on your meter and confirm it is displaying in K-ohms.

FYI, 7.8 K-ohms = 7800 ohms (move the decimal three places to the right) and 8.6 K-ohms = 8600 ohms.

I'm locked out of my service library right now, but will look into the flywheel / magnet area to see if there's anything odd there. Stand-by.

 

[danl1950]

Unlikely brand new coils are bad.

Keep in mind, the secondary measurement is in K-ohms, which is thousands-of-ohms. Check the scale selection or range on your meter and confirm it is displaying in K-ohms.

FYI, 7.8 K-ohms = 7800 ohms (move the decimal three places to the right) and 8.6 K-ohms = 8600 ohms.

I'm locked out of my service library right now, but will look into the flywheel / magnet area to see if there's anything odd there. Stand-by.

Took the coils,old and new,to a guy that had a coil tester and 1 of the new coils was defective,both old ones were good.Couldn't think of why these coils weren't firing,so I thought I'd try swapping sides,since both coils are identical on the outside.They're labeled "left" and "right",so I suppose they're wired differently on the inside.I put the "left" one one the right side and cranked the engine and had all kinds of fire,same on the left side.I was afraid it might put the engine out of time but it runs just fine.Please explain why they work on the opposite side that they've been running on for years,just don't make sense to my.

 

[robert@honda]

The GX620 had a number of different coils, ignition, charging, etc., and they were subject to some running changes. Early GX620's had different left and right coils (different part numbers), and later models shared the same part number/coil.

If you could get me the serial number off the side of the engine block, I could narrow it down a bit more. It's in the form of: "GCAD-1234567"