82 evinrude 150hp V6 running rough

cb950

Seaman Apprentice
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Jul 21, 2004
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30
Hello, <br />I have a motor that has an intermittent problem. The plugs all seem to spark, though not very bright(can hardly see it in daylight). I can get the motor to start, it is properly sync'd and linked (I've had the timing at 6, 7 and 8deg) BTDC. When I get it to start it will sometimes idle perfect at 700rpm, and purr, other times it will sputter, and miss, and pop, and eventually stall. If i gun it, it will sometimes work fine, and other times it will bog, or sputter up to speed, or stall. I want to say this is probably an ignition problem, but Here are the only strange things I noticed. The carbs all have different liter per hour ratings on a tag on the side. (the top is 20Lph, the middle is 10, and the bottom is 7). I noticed that with the engine running the middle one seems to be sucking a whole lot more air in then the top or bottom, (just by putting my hand in front of it.) Does anyone know if that is normal? The cylinders all have good equal compression. The only other thing that i noticed, is that the wires coming out of the timer base were smashed in the little guide thing that they go through on the way to the power pack. I got them unsmashed, but shaking them doesn't seem to make the engine misbehave or change anything for that matter. I can't seem to make the engine misbehave, it just sort of intermittently goes back and forth from good to bad, with nearly every start or every time i give it throttle Any ideas of how to go about diagnosing this problem would be greatly appreciated.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 82 evinrude 150hp V6 running rough

Rig up a spark tester where you can set a 7/16" gap.<br /><br />Spark plugs removed. Spark should jump that gap with a strong blue lightning like flame, a real SNAP!<br /><br />If not, disconnect the large RED electrical plug at the engine. Re-check spark. If spark is now as it should be, replace the ignition switch as it is in all probability shorting out.<br /><br />If still no spark, check the stator under the flywheel which is the beginning of the ignition and charging system. If that stator is cracked and/or melting down in any portion, replace it.<br /><br />Note that the engine must crank over at least 300 rpm in order for the magnets in the flywheel to affect the stator.... to have the stator generate approximate 300v AC to the powerpack(s). A slow cranking engine will obviously have a strong effect on the starting of the engine.
 

cb950

Seaman Apprentice
Joined
Jul 21, 2004
Messages
30
Re: 82 evinrude 150hp V6 running rough

I Checked the spark by just holding the plug like a half inch away from the block. They are sparking, but im not sure if it is strong enough. I posted a video below. So then I took my flywheel off, and the stator looks fine, although metal doesn't magnetically stick to it like it does to the flywheel, is that normal? Anyway, I put it back together, c;eaned all the plugs, and i can get the motor to run for about 45 sec perfect, then it starts to crap out, and all my spark plugs look like this<br />
spark.jpg
<br />here is a video of my spark plugs sparking, I don't know if they should spark brighter? spark video <br />Any help would be greatly appreciated. Thanks!
 

angus63

Captain
Joined
May 20, 2002
Messages
3,726
Re: 82 evinrude 150hp V6 running rough

Looks real wet to me.<br />Try UL77V champ plugs gapped at 0.040"<br />Never did like surface gap plugs<br />Good luck
 

walleyehed

Admiral
Joined
Jun 29, 2003
Messages
6,767
Re: 82 evinrude 150hp V6 running rough

UL77V is a surface gap plug....<br />How'bout a QL77JC4 gapped at .040.....
 

angus63

Captain
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May 20, 2002
Messages
3,726
Re: 82 evinrude 150hp V6 running rough

OOPS!!!!<br />Saw that and the L16V on the chart and assumed...<br />Like I said, don't like em, don't use em.....<br />Thanks for the heads up
 

cb950

Seaman Apprentice
Joined
Jul 21, 2004
Messages
30
Re: 82 evinrude 150hp V6 running rough

Thanks guys I will try that. will someone watch my video, and see if it looks like my ignition is FUBAR? That might be why they are getting so wet. You probably have to right click then save as on the link below.<br />Thanks,<br />CB<br /><br /> SPARK VIDEO 3.5mb
 

angus63

Captain
Joined
May 20, 2002
Messages
3,726
Re: 82 evinrude 150hp V6 running rough

Saw it and tough to tell since your gap wasn't a fixed length. Really need to judge it in person.
 

cb950

Seaman Apprentice
Joined
Jul 21, 2004
Messages
30
Re: 82 evinrude 150hp V6 running rough

Allright, <br />I pulled the trigger and spent the 6 dollars on a spark tester. Had no idea they were that cheap! Also bought a fuel pressure guage. gonna test both of these things and get back to you guys. <br /><br />I swapped a blown up force 150 for this engine, there isn't an electric fuel pump for mercury engines that shouldn't be there right?<br /><br />I was reading in my seloc book, and decided to check my cylinder drain check valves. assuming i did the test correctly, (syringe in to the nipples below each carb) it appears they are stuck open. i thought this was weird that all of them would be broken, so i figured I must have misunderstood the test. Would this cause the plugs to foul?
 

Muddy Paws

Seaman Apprentice
Joined
Mar 20, 2005
Messages
31
Re: 82 evinrude 150hp V6 running rough

$6 spark tester? Where did you get it?<br /><br />I was going to make one, but not if they only cost 6 bucks.<br /><br />Is it for one plug at a time?
 

lastout

Petty Officer 3rd Class
Joined
Jul 5, 2003
Messages
93
Re: 82 evinrude 150hp V6 running rough

that tester from harbour freight won't let you test the jump gap. it does no more really than holding the plug to the block the way you were. simply lets you know spark is there.
 

cb950

Seaman Apprentice
Joined
Jul 21, 2004
Messages
30
Re: 82 evinrude 150hp V6 running rough

Fixed it! <br />I got a cheap spark tester from auto zone. It told me at least that the spark is consistent. After I rebult the carbs, (which looked fine inside), got all new ql77jc4 spark plugs, (thanks angus and walleyehed!), broke down the fuel pumps, and cleaned them up, (they looked fine inside), and replaced all the fuel line, (there were some cracks in some pieces), and tested all the ignition parts that i could with a regular multimeter, (the coil resistance was 585ohms, even though it was supposed to be at least 900 as per my seloc book) it fired up, and runs like a top, I'm dropping it in the water to see for sure today. Thank you Everyone for your help!
 
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