73 4hp Evinrude sparks-very odd problem.

[Nos4r2]

Just been servicing my auxilary and it wouldn't start. Checked spark, cleaned fuel system out etc and all seemed ok.<br /><br />Then I put a strobe on it and found out that it won't spark with the plugs IN, but it WILL spark with the plugs out and touching the casings. I got it to run by closing the plug gaps up, but it ran for about 2 minutes then stopped sparking again-but would still spark with the plugs out.<br /><br /> The plugs had been changed just before the end of last season and have only had 5 minutes of running time.<br /><br />Should I be looking at new plugs or an ignition system failure further back?<br /><br />By the way, does anyone know what the settings for the slow and fast idle screws on the front of the carb should be? They aren't in my manual and the previous owner had been 'playing' with them...<br /><br />Cheers Guys!

 

[OBJ]

Re: 73 4hp Evinrude sparks-very odd problem.

I would take a look at the points first. Sounds like either they are burnt or need re-gapped. Also, while under the flywheel, take a look at the coils. If they are cracked and look like they've seen the better part of use, replace them.<br /><br />Rough needle setting, start with 3/4 open from GENTLY seated on the high speed and 1 turn open on the low speed. Set the high speed first, get the engine up to temp and come down to idle in gear and adjust the low speed for best idle. Carefull not to set the low speed need to lean (closed direction). After you get it to where you like it, open the needle about a quarter turn. This will help to keep it from running to lean.

 

[ezeke]

Re: 73 4hp Evinrude sparks-very odd problem.

Uno itinere non potest perveniri ad tam grande secretum.

 

[Paul Moir]

Re: 73 4hp Evinrude sparks-very odd problem.

I agree with OBJ, try cleaning and regapping the points (.020") for starters. I use 600 grit folded over a thin feeler gauge, and the pressure of the points. Then a quick q-tip (er, cotton swab) of acetone to remove any oil, etc.<br /><br />To prove it's not the plugs, try setting it up to jump a 3/8" gap. The 4hp should do that pretty easily. That simulates firing under compression.

 

[Nos4r2]

Re: 73 4hp Evinrude sparks-very odd problem.

Thanks OBJ and Paul, I'll get under the flywheel in the morning and update this afterwards. I was kinda hoping not to have to but needs must I guess...Spent an hour this afternoon recoiling the starter spring after it fired itself out.<br /><br />I think I kinda got lost on the sparks a bit-the spark was big and strong with the plugs out. Will set up a 3/8 gap tester too.

 

[OBJ]

Re: 73 4hp Evinrude sparks-very odd problem.

ezeke.....you on oil agin???????

 

[ezeke]

Re: 73 4hp Evinrude sparks-very odd problem.

Working up to it, OBJ. <br /><br />Rained all day,40 outside.

 

[OBJ]

Re: 73 4hp Evinrude sparks-very odd problem.

That sucks..... Ran around yesterday in shirtsleeves.....today....froze the kahunies off on the way to the shop......even sleet.

 

[Vic.S]

Re: 73 4hp Evinrude sparks-very odd problem.

As the plugs are almost new they are unlikely to be the trouble. Cleaning and adjusting the points is the next thing to do together with a visual inspection of the coil.<br /><br />So far I don't think anyone has mentioned the condenser. The symptoms described all suggest that it could be the cause of the problem. The only way to check though is to replace it with a new one.<br /><br />The final possibility is that the magnets have lost their power

 

[Nos4r2]

Re: 73 4hp Evinrude sparks-very odd problem.

Got the flywheel off-Coils are covered in deep cracks right through to the windings and points were a bit burnt. Guess I've found the problem... <br /><br />Anyone got the part number for the coils?

 

[Nos4r2]

Re: 73 4hp Evinrude sparks-very odd problem.

Scratch that-its 18-5181 isnt it?

 

[Paul Moir]

Re: 73 4hp Evinrude sparks-very odd problem.

Yes, that's the Sierra aftermarket part. Personally I like them a lot better than the factory part 584477. I get them around here for about $25CAD each. Either way, it looks like they finally got the cracking plastic problem licked.

 

[Nos4r2]

Re: 73 4hp Evinrude sparks-very odd problem.

Hell, anything's got to be better than 32 year old electrics! <br /><br />Cheers Paul.