Briggs and Stratton Intek v-twin 20hp

[Auto Doc's]

The harness has to be removed from the engine and the diodes uncovered/exposed to test each with an Ohm meter.

When people (DIY and mechanics both) do not understand diodes and testing with a meter, that's when problems happen. I know many self-proclaimed "small engine mechanics" who know nothing about testing anything electrical, they only know to keep replacing parts.

Of course, it does not help that engineers put the tiniest fragile diodes they could in the wire circuit. (Designed to fail)

 

[CLStout]

The harness has to be removed from the engine and the diodes uncovered/exposed to test each with an Ohm meter.

When people (DIY and mechanics both) do not understand diodes and testing with a meter, that's when problems happen. I know many self-proclaimed "small engine mechanics" who know nothing about testing anything electrical, they only know to keep replacing parts.

Of course, it does not help that engineers put the tiniest fragile diodes they could in the wire circuit. (Designed to fail)

Are there alternatives to the diodes?

 

[Forest#2]

Are there alternatives to the diodes?

No. Not really on the Briggs twin Inteks engines.

The diodes usually fail due to a external cause. (for example a leakage current in the ignition switch)
But as you found they can be a real pain when one gets intermittent erratic

I don't remember the 1NXXXX numbers on the diodes I use as replacements, I have it wrote down in the service manual but they have a higher Peak Inverse Voltage rating (PIV) and the amps rating is little bit higher than the OEM. I've never had my replacements fail UNLESS someone connects the battery backwards or jumps to the battery from another battery with wrong polarity OR if the key switch gets rust inside and applies a pos voltage to the kill wire going to the coils. If they fail again I would replace the ign switch. A leakage voltage/current inside the ign switch to the M (kill terminal) will put a forward bias on the diodes and wipe them out fast. When one is bad it upsets the 2 magneto coils ignition internal electronics firing. (the coils are NO LONGER isolated from each other and the opposite coil can possibly fire when the valves are open (fires at wrong time)
The older model Briggs twins used two coils but they did not require the diodes for isolation.

I also do as one of the guys suggests I keep a spare diode harness for the Briggs twin Inteks and just swap the harness and repair the bad one in my spare time. I have electrical testers and know how to test the diodes for reverse leakage, but it's best to just replace the harness or replace both diodes and test because sometimes a diode will get erratic failures (not bad all time)Kinda like being just a little bit pregnant.

I'll make a note and get back to you with the 1NXXXX designation. they are dirt cheap from Radio Shack and if not in stock they can order) or a electronic retailer. (I do not trust doing the ebay or amazon China diodes) After replacing the diodes use heat shrink tubing over the diodes and bare wires.

 

[CLStout]

No. Not really on the Briggs twin Inteks engines.

The diodes usually fail due to a external cause. (for example a leakage current in the ignition switch)
But as you found they can be a real pain when one gets intermittent erratic

I don't remember the 1NXXXX numbers on the diodes I use as replacements, I have it wrote down in the service manual but they have a higher Peak Inverse Voltage rating (PIV) and the amps rating is little bit higher than the OEM. I've never had my replacements fail UNLESS someone connects the battery backwards or jumps to the battery from another battery with wrong polarity OR if the key switch gets rust inside and applies a pos voltage to the kill wire going to the coils. If they fail again I would replace the ign switch. A leakage voltage/current inside the ign switch to the M (kill terminal) will put a forward bias on the diodes and wipe them out fast. When one is bad it upsets the 2 magneto coils ignition internal electronics firing. (the coils are NO LONGER isolated from each other and the opposite coil can possibly fire when the valves are open (fires at wrong time)
The older model Briggs twins used two coils but they did not require the diodes for isolation.

I also do as one of the guys suggests I keep a spare diode harness for the Briggs twin Inteks and just swap the harness and repair the bad one in my spare time. I have electrical testers and know how to test the diodes for reverse leakage, but it's best to just replace the harness or replace both diodes and test because sometimes a diode will get erratic failures (not bad all time)Kinda like being just a little bit pregnant.

I'll make a note and get back to you with the 1NXXXX designation. they are dirt cheap from Radio Shack and if not in stock they can order) or a electronic retailer. (I do not trust doing the ebay or amazon China diodes) After replacing the diodes use heat shrink tubing over the diodes and bare wires.

I was able to locate the correct diode (1N4007) which I purchased and made a new harness. I made a new connection after the plug in the OEM harness for ease of removal in case I have further issues. It was more of a PITA to install the kill switch harness than it was to make it.
I would appreciate it if you could post the numbers for the diodes you used in case mine go belly up.

 

[slomo]

OK, I understand. But it's a new, never been used gauge. This is literally the first time I've had it out of the box. And with the numbers for compression that the manual says it should be, I thought it was a good number. The instructions say it can be used for any type of engine.

New doesn't mean it works, as new. Just stating the obvious.

Most people look at purchase time trying to equate some level of quality.

 

[Forest#2]

I was able to locate the correct diode (1N4007) which I purchased and made a new harness. I made a new connection after the plug in the OEM harness for ease of removal in case I have further issues. It was more of a PITA to install the kill switch harness than it was to make it.
I would appreciate it if you could post the numbers for the diodes you used in case mine go belly up.

I checked and the 1N4007 is what I use. They are trouble free unless molested.
I think maybe a guy by the handle of Star tech on this site recommended those to me few years ago.

 

[CLStout]

I checked and the 1N4007 is what I use. They are trouble free unless molested.
I think maybe a guy by the handle of Star tech on this site recommended those to me few years ago.

Thanks! I have a handful of those that I purchased recently. They seem small compared to the OEM ones, but currently they are working just fine.