how do you test the power supply or coils?

[mhcooper84]

to see if they are going bad

 

[Joe Reeves]

Re: how do you test the power supply or coils?

You'll need to tell us the year, make, and hp of the engine you're speaking of, and a explanation of the problem you're having.

 

[mhcooper84]

Re: how do you test the power supply or coils?

82 evinrude 70hp and the problem is it goes fine for about 15 mins and I stop then wait about 10 to 15 and try to start it and it wont crank easy and I cant get it above 2k rpms

 

[mhcooper84]

Re: how do you test the power supply or coils?

any good ideas how to test this?

 

[durban]

Re: how do you test the power supply or coils?

this sounds like a stator problem to me when the motor is cold it will start right , & as the motor warms up so does the stator , when you try & start it again while the stator is still warm it wont start , let it cool down after some time & try again , if it starts then its the stator playing up , simple test to see if your coil is working swop them around .

 

[boobie]

Re: how do you test the power supply or coils?

To test electrical parts on a mtr, you need an OEM Factory service manual, an open air gap spark tester and a multi-meter with a DVA adapter.

 

[Joe Reeves]

Re: how do you test the power supply or coils?

82 evinrude 70hp and the problem is it goes fine for about 15 mins and I stop then wait about 10 to 15 and try to start it and it wont crank easy and I cant get it above 2k rpms

Look under the flywheel at the stator. There are three large coils within that ring that deliver approximately 300 AC volts to the powerpack in order to energize the ignition. Should is be starting to melt down for any reason, it might act normal when cold BUT after it heats up, a voltage drop would exist that would result in weak, erratic, and eventually no ignition.

Should this melt down be taking place, a sticky looking substance would be dripping down upon the timer base and powerhead area. If this is the case, replace the stator.

You need to check the compression... what are the psi readings of each cylinder?

Check the spark... it should be a strong blue lightning like flame that will jump a 7/16" gap, a real SNAP! The 7/16" gap is important! What do you get when the engine is quite cold..... and when it is acting up?

Also.... the term CRANK pertains to having the electric starter "cranking" the engine over. Are you saying that when the engine is hot, the engine CRANKS BUT will not START properly?

 

[snowseeker]

Re: how do you test the power supply or coils?

Look under the flywheel at the stator. There are three large coils within that ring that deliver approximately 300 AC volts to the powerpack in order to energize the ignition. Should is be starting to melt down for any reason, it might act normal when cold BUT after it heats up, a voltage drop would exist that would result in weak, erratic, and eventually no ignition.

Should this melt down be taking place, a sticky looking substance would be dripping down upon the timer base and powerhead area. If this is the case, replace the stator.

You need to check the compression... what are the psi readings of each cylinder?

Check the spark... it should be a strong blue lightning like flame that will jump a 7/16" gap, a real SNAP! The 7/16" gap is important! What do you get when the engine is quite cold..... and when it is acting up?

Also.... the term CRANK pertains to having the electric starter "cranking" the engine over. Are you saying that when the engine is hot, the engine CRANKS BUT will not START properly?

Sorry, I've been searching and reading about a problem I have been having for a couple years now. I just rebuilt a 91 70hp evinrude (motor, carbs, and all). Perfect compression and fuel adjustment. But when the motor sits for a month or more it won't have spark on any cylinders. I have a spare (running) motor that I tried everything from coils, to stator, to flywheel on my motor when there is now spark and nothing seems to fix it. Then randomly it will just fire off and run like normal and start every time like it should even a day or more later. But then it sits for a month and no spark again. The few times I thought I hit the culprit part with one from the donor motor but it acts up again in a month. This last time I didn't get to try the motor before leaving for camping so i had to put up with it at the lake. After pulling plugs, cleaning the fuel off, jiggling some wires, and cranking it for awhile it finally fired and then ran perfect all week. No parts swapping this time.


I am at a loss, even when there is spark it does seem weak and this is the reason I quoted you with your 7/16" comment. With my spark tester if I try to open the gap anywhere past 3/16-1/4" no spark. But like I said I tried coils, plug wires, tried stator, flywheel, different cdi, the works. I would think if it was a bad electrical connection I would have more periodic luck with the ignition.

http://forums.iboats.com/showthread.php?t=97206