Can a faulty switchbox damage trigger?

[Nautique93]

1983 Mercury 70HP Power loss.
Can a faulty switchbox damage trigger or stator? I replaced stator as readings were well out of spec. Trigger read in spec. Full power returned for a couple of trips, then suddennly dropped to half power. New stator still tested good, but trigger now tested well out of spec. Are these components coming to the end of there life or could my switchbox be damaging them? I initially bought a used switchbox cheap when i first started having problems, and swapping switchboxes didnt affect the symptoms. Tryed swapping switchboxes again when the trigger gave up, with no change. Im worried either one of thses switchboxes could be damaging new parts, and should i spring for a new one of these as well, even though the switchboxes dont appear to be the problem?
Thanks, Peter

 

[Evinrude Boater]

Re: Can a faulty switchbox damage trigger?

Describe "dropped to half power". I take it, it will not rev up past 3000 rpm. If so it's probably the high speed coils in the stator. Go to CDI electronics.com, read through the troubleshooting sections then determine what the problem is. I doubt the used switch box is affecting the trigger or stator.

 

[Nautique93]

Re: Can a faulty switchbox damage trigger?

Thanks, that is correct, wont rev past 3000 rpms. New stator cured this, worked for about 6 hours, then dropped to 3000 rpms again. New stator still checks good, but trigger is now out of spec. Should be 700- 1000, one pair is reading 2500, and the other is 1250. Ive read a faulty trigger would also cause the symptoms im seeing, is this correct? Cant decide whether to replace switchbox as well as trigger. Peter

 

[Evinrude Boater]

Re: Can a faulty switchbox damage trigger?

Sounds like the trigger is buggered too. The CDI site has tests for the switch box and coils which you might also explore.

 

[RaScLeS]

Re: Can a faulty switchbox damage trigger?

double post

 

[RaScLeS]

Re: Can a faulty switchbox damage trigger?

the trigger will cause the same problems, i swapped mine for new,4-6hrs later it was shot, im still finding out if its the trigger or the stator or anything else. does any reader have a good link with test results or a howto diagnose ignition problems on a 79-80 merc 70hp ?

which cylinder on your engine is not firing ? what is the compression and how reliable do you think the 70 is ? ive had one for the summer and its been brutal. i think were on the same boat with our motors keep in touch.

 

[RaScLeS]

Re: Can a faulty switchbox damage trigger?

bump

 

[Laddies]

Re: Can a faulty switchbox damage trigger?

Always use a DVA for best test results.

 

[Nautique93]

Re: Can a faulty switchbox damage trigger?

I have only taken ohm readings, Initially i had a temperamental issue with high speed, Learned how to take ohm readings and what the correct values should be, and found when it was working the readings were in spec, and when it wasnt the stator was well out of spec. Fitted new stator, cured problem for a couple of trips, then suddennly dropped power and wouldnt go over 3500 revs. (When the stator was out of spec it wouldnt go over 3000 revs.) Tested trigger and stator again, this time the trigger is reading way out of spec. The new stator still tests ok. So, i have ordered a new trigger. If this doesnt fix the problem, or if i have problems in the future i will invest in a DVA meter, as it probably would of shown up the trigger problem when i diagnosed the stator, saving me 2 lots of postage to the UK and me taking the flywheel off twice.
I started this thread as i was concerned that the new stator and trigger may be damaged if my switchbox is faulty, which cant be tested without a DVA meter as far as im aware. As no - one has expressed concern that it could, ive just ordered the trigger, hoping that the switchbox is in fact ok.
By the way i dont think im losing a cylindar, ive tested with spark tester but only at idle, so it could be dropping one under power. I believe from my readings that the timing is not advancing correctly/ or at all, causing my problem. We will see if the new trigger cures it!
Peter

 

[RaScLeS]

Re: Can a faulty switchbox damage trigger?

please update it, I think i've got the same issue, so when i get time to do the tests shown it should be inspec and the stator out of spec. will see soon,

when doing the test its with the motor on ? or off for 1 cylinder not firing ? and the black wire on the dva is always on the black wire of the switchbix while doing this ?

 

[Nautique93]

Re: Can a faulty switchbox damage trigger?

I have never tested with a DVA, i believe this is done with the motor running to check the voltages being produced.
If you are ohm testing the stator coil or trigger coil the engine is off, battery disconnected and the wires disconnected from the switchbox. If you leave them on the switchbox while testing i believe you will get false readings.
I will update when my trigger arrives, but it could be up to 6 weeks according to iboats. When i ordered the stator it came in about 3 weeks.
Peter

 

[RaScLeS]

Re: Can a faulty switchbox damage trigger?

how much for the parts ? i got my trigger in a few days for $180cad