tester to jump cylinder

Sylva-Ranger

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I whant to build a kind of tester for myself, for troubleshooting by jumping one a time each cylinder. to insulate and compare cylinders when ignition is OK and not suspected. In fact, that device do the same as pulling sparks-plug wires during engine running, but more safe for the operator and the ignition system , and more easy to do.

​In fact, it's a simple box whit 4 wires (one to each cylinder), a big grund wire that connect to the engine,and 4 switchs to cut each cylinder by conecting to the grund . It's for 2-4 cylinders engines.

​I'm not sure if its better to jump cylinder by the sparks-plug wires or by the primary of each coil ? I think by the sparks-plug wire i'ts more universal for every engine and easy to do ?

​What kind of switch use ? Do a simple 12 volts on/off toggle switch will do the job ? Or the hi voltage (if use on spark plugs wires) will jump the gap directly to the ground side of the switch ?

What di you think about my diagnostic tool ?
 

Sea Rider

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Personally would prefer a spark tester to check jumping spark strength. Grounding spark won't tell its strength.

Happy Boating
 

Sylva-Ranger

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This is not for the same purpose, it's for use afters the spark test, not to replace it
 

Faztbullet

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Break it on the primary imput side....CDI makes a breakout box for this for Johnrudes
 

Sylva-Ranger

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What is benefit to break to the primary side ?

Because on the the secondary side it's universal for most engine make/models........In the primary side there many kind of plug-in, and probably many adaptors to isluate the good wire ?
 

Don Hansen

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On the primary side you're only switching 12 volts. Where are you going to find a switch that will handle the 30K+ on the secondary side without arcing between the open contacts.
 

Sylva-Ranger

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I think to use a metal ground,maybe flat bar activate by a lever Inside de device That mechanically short to another plate that contact by a good size wire routed to engine , or a little device like some stop switch on some old Briggs & Stratton engine........
 

gm280

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Sylva-Ranger, the problem with making anything to switch the high voltage on the secondary side is the high voltage itself. Unless you buy high voltage switches, and they are not going to be easy to find and probably expensive if you do find them, the typical toggle type switch will not handle the high voltage for long before burning out. If you ever opened up a toggle switch, the "make" and "break" lever inside is merely not that large and when it is not in the "make" position, and the contacts are merely thousands of an inch opened. Any spark could easily jump those contacts and burn then quickly. Unless you can construct something that opens such contacts by an inch or more, you will have problems with it eventually. JMHO
 

Silvertip

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Any switch in the high tension circuit will not only jump a sizable gap, but would likely jump up your arm as well as soon as you touched the switch. Therefore, switch the primary side of the system.
 

Sylva-Ranger

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The switch can be easily will be insulated and not operated directly by metal part whit my hand , like i try to explain, and can easily have a gap ok 3" or more to insure that ignition can't jump the gap. On and old Briggs & Stratton you have the grounding clip that stop the engine on the Spark-plug right in your fingers and you don't take the voltage .

​Maybe me and the guy in the link above are not right, but i think i'm better to spend a little bit more time to make a device that jump on the secondary side of any past or present engine, that have to make new adaptor (and spend time to plug/unplug ) to jump primary side each time a new make/model is tested.

​On some model is easy to jump primary side,espeacialy whit wires bolt on the coils, but on some other you have to make plugs/jumping wires that fit correctly and insulated the good wire Inside a many wires plug.

​Do you realy think is impossible do build a tester that work for jumping secondary side ? What to you think about the tester in the link ? me i like the double use (gap tester/jumper) .
 
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ondarvr

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How much do you plan to use this device? It seems like it would be very handy on a 6 cylinder motor, but I can't say that I've needed one very often for personal use.
 
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Sylva-Ranger

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I'm small engine mechanic, i do some repair on snowmobiles, atvs and some small outboards (2-75hp) and i realy think a device like that may be useful for some troubleshootings, on 2 cylinders or more engines.

​On snowmobiles, some time we remove spark-plugs wire one at a time to check if cylinder operated properly. I think a device like will make the job more easy a more safe, for the operator and for the ignition system.


I'm usualy not working on 6 or 8 cylinder , but if is the case, i can use 4 cylinder tester just by not testing all on the same test, just begin by the forst 4 cylinders and after that, test the remaining.

​I'm conscious that is easyer to build a device that work on primary side, but on some engine the primary side is not always easy to reach in the wiring and sometime work whit multiples special plug-in.

​On many engine whit double coils, the primary is the same for 2 cylinders, that makes if you jump one cylinder by the primary, that means that you jump the oposite cylinder too, and the engine whill stop completely , if its a 2 cyl or on lost 2 cylinders (2 cylinders bank) .

By jumping on the secondary side, the engine will probably continue to work on the oposite cylinder.
 

gm280

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Sylva, Not criticizing your ideas, only offering opinions. But you have to make the final decision for your application. We all only offer suggestions and opinions. The person has to do what they think is best. Just be careful. JMHO
 

Sylva-Ranger

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Sylva, Not criticizing your ideas, only offering opinions. But you have to make the final decision for your application. We all only offer suggestions and opinions. The person has to do what they think is best. Just be careful. JMHO

Thank you gm280

​I'm conscious that people just offer sugestions and opinions.........I'm just tinking, if everyone think is a bad idea to jump to secondary instead of primary, in spite the reasons i explain , may be i'm totally wrong

And i have to admit that is hard for me to use English for talking in a forum (i'm french canadian) and i try to expalin the best i can.



​I like this forum, there lot of knowledge peoples !
 

Sylva-Ranger

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Finaly i make my device just whit a piece of flat bar, old sparks plugs and spark-plug wires, a piece of wood and somes screws, and that work great.

​And no danger to take spark, the buton is make always contact on the iron plate and this plate is always to ground,

​The switchs are just peaces of iron and bolt,, there easy to replace if they camme damage

​Make my first test , just need to make a better ground wire and some smalls and estetic.

​The device can also be use as an adjustable ignition spark-tester, by select the switchs as the desired gap

https://www.youtube.com/watch?v=aoRS...ature=youtu.be
 
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jerryjerry05

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In 1987 I bought something like this from MAC tools.
Called a cylinder balance analyzer.
​Pretty sre it won't work on an outboard unless it has a distributor. but it was good for checking carbs and what cyl. might not be firing.
 

Sylva-Ranger

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Westerday someone bring me a 2005 Merc 25 hp 4 strokes that seem to run uneven or run only on one cylinder.........On that model like many 4 strokes there only one coil for both cylinder (and only one primary wire).

​Compression was ok (just 5 PSI lower on botom cylinder) , inginition was good and inductive RPM reed the same for both..

plug my device and grund the bottom cylinder , no significative RPM drop.........grund the top cylinder and the engine drop and stop.


​Assuming is only one carburetor and seems have no air leak, i decide to check valves clearance : one of the bottom one was very tight........Adjusted the valves and engine now running ok,

I rested whit my device, the RPM now drop exactly the same for both when i ground each one.


​Just need to make a better and more pratical ground wire for my Tools .mabe add a build-in tachometer .
 

cfauvel

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Aug 16, 2005
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645
Westerday someone bring me a 2005 Merc 25 hp 4 strokes that seem to run uneven or run only on one cylinder.........On that model like many 4 strokes there only one coil for both cylinder (and only one primary wire).

​Compression was ok (just 5 PSI lower on botom cylinder) , inginition was good and inductive RPM reed the same for both..

plug my device and grund the bottom cylinder , no significative RPM drop.........grund the top cylinder and the engine drop and stop.


​Assuming is only one carburetor and seems have no air leak, i decide to check valves clearance : one of the bottom one was very tight........Adjusted the valves and engine now running ok,

I rested whit my device, the RPM now drop exactly the same for both when i ground each one.


​Just need to make a better and more pratical ground wire for my Tools .mabe add a build-in tachometer .


just saw what you did on youtube..bravo...ca marche!!
 

Sylva-Ranger

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Jan 17, 2016
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I used my tools many times this summer for diff?rents troubleshooting and i like it.

​The only one thing make different is put a better ground whit better clips whit a larger wire.

​First tinking that grounding switchs , whit just a metal part touching a small srews, will not do the jump and/or spot and burn fast..........but that work verry well again.

​Switching every cylinders, one at a time , and watching and compare RPM drop is a good way to know if every cylinders do their job, and if not witch one is faulty.

​By switching grounding knob at a certains gap, i can figure own strong is the spark on a particular cylinder during engine operation.
 
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