spark plug tester question

[wpg manitoba]

I was thinking of purchasing one of those but am not totally familiar with them. My problem is I know my outboard has spark but I am wondering if it is losing spark when it shuts off all of a sudden. Am I able to run an engine with the spark plug tester connected to confirm there is spark when it shuts off?

 

[Silvertip]

Re: spark plug tester question

That's not a spark PLUG tester. It is a SPARK tester. An engine generates spark whether it is actually running or if it is being spun by the starter but NOT running. Yes - a spark tester confirms whether or not spark is present. But after the engine stops, there will obviously be no spark unless you crank the engine.

 

[glenn property of pam]

Re: spark plug tester question

they havent made a spark monitor for years now as fuel injection computers can spot miss fires so theres realy no market for the gauge. if the engine is cutting out then even the best monitor they made back then proberly wouldnt help you as the time between engine power loss and the engine spinning to produce the spark on a outboard in gear would be to close to call. the spark plug tester is to test the strenth of the ignition system it doesnt test the spark plug. plugs are cheap so im not sure they even make a plug tester anymore as its cheaper to replace them then to pay the labor to test them. a modern tach/timing gun can be hooked to the lead and used as a crude tester but that would be to test for a single plug dropping causing a loss of power from a bad coil. you may be better off listing your make and model on the outboard forum with as much detail of what the engine is doing when it cuts out as most outboards (carbs) run on there own once started and the electrical on the boat has to force the engine to stop rather than being required to keep the motor running.

 

[sschefer]

Re: spark plug tester question

Actually, you can buy a inline tester at O'Reily's. They fit on the plug and then the plug wire fits on the end of the tester. These are single units so you'd need to get one for each plug. They are clear plastic and you can see the spark jump. I bought one and tried it and it worked o.k. but I was working on Merc V-6 motors mainly so I went with the CDI tester instead. That type you cannot use with the engine running. For what I think you're trying to do, the inline might work.

 

[wpg manitoba]

Re: spark plug tester question

I didn't understand that to well. I figured when it shutts of that I could see if its still producing spark as the engine comes to a halt? That would indicate to me that the spark is still firing and must be a fuel problem? Sorry, just have limited experience.

 

[sschefer]

Re: spark plug tester question

I didn't understand that to well. I figured when it shutts of that I could see if its still producing spark as the engine comes to a halt? That would indicate to me that the spark is still firing and must be a fuel problem? Sorry, just have limited experience.

Humm, that's probably going to be pretty tough. Then engine won't wind down slow enough for your to see if it's spark or not. If it's a fuel problem it will loose power first and then shut down. It's rare that fuel causes an immediate shutdown as if the key was turned off.

 

[Silvertip]

Re: spark plug tester question

Why don't you tell us what engine you have and what the symptoms are. Does this happen at ANY throttle/speed setting? Does it happen only after the engine is hot. We can probably help but not if we don't know what the symptoms are.

 

[wpg manitoba]

Re: spark plug tester question

1987 mariner 30hp 2 stroke,
Ussually it starts up real easy, but will only run for 30-60 seconds then all of a sudden it just turns off like someone turned the key off. Then usually it won't start again untill an hour later. I should check for spark when it does this I guess, then that would probably confirm it must be fuel.

 

[sschefer]

Re: spark plug tester question

Correct, one of the inexpensive inline spark testers should work just fine for you. Start it, let it stall, put the spark tester on it and then crank it and see if you have spark. It almost sounds like a problem in the lanyard stop switch.

 

[glenn property of pam]

Re: spark plug tester question

check both plug (im presuming thats a twin) as it sounds like a coil that fails when hot.

 

[Jlawsen]

Re: spark plug tester question

check both plug (im presuming thats a twin) as it sounds like a coil that fails when hot.

That's was my first thought until he said 30-60 seconds. I'm thinking that's just about enough time for a worn down lanyard switch to vibrate to the closed positon. It is an 87 and that switch has probably seen a lot of use over the years. I have to agree with sschefer and would at least check it out.

 

[glenn property of pam]

Re: spark plug tester question

i agree with sschefer but if you are going to test one why not take a min and check the other just for good measure.

 

[Jlawsen]

Re: spark plug tester question

i agree with sschefer but if you are going to test one why not take a min and check the other just for good measure.

LOL, yes of course, sorry didn't mean it to sound like the wrong thing to do.

 

[glenn property of pam]

Re: spark plug tester question

lol np 30-60 does sound to quick for a coil unless its been doing it a while but as the op has a hour to wait it wont hurt to test it.

 

[wpg manitoba]

Re: spark plug tester question

forgot to mention though it's not a tiller. When I get a chance thats what I'll do see if it has spark after it shuts down and won't start again.

 

[wpg manitoba]

Re: spark plug tester question

Spark looks good I think it's the fuel pump. From my understanding I can disconnect the fuel line after the pump, crank start it and see if it's pumping anything. Also when it stalls I have noticed it will start up again if I pump the gas alot. It's gotta be the pump for sure.

 

[MH Hawker]

Re: spark plug tester question

I use one of the older style spark gap testers it can show a weak coil,

It can be a fuel line fitting sucking air and wont pull enough. If their is any sign of a leak any place past the primer bulb