1995 Mercury 2.5l 175hp carb ignition issues

[Rider_560]

I really appreciate the help so far! I'll keep you guys in the loop!

[Rider_560]

Fishinmymission, I'll take you up on those boxes if you get your hands on them.

Merclovers, I may take you up on the stator and rectifier if needed. I'm still waiting on the dva.

I appreciate the help

[Merc 2.5]

Try boxes 1st and go from there, unless it just test bad but I doubt it, I been through exact same thing and boxes fixed it, at the time I only changed 1 box and on the 2nd trip the other box went out, swapped to a pair and all was good. Good luck

[Rider_560]

Great. I'd imagine the china boxes could well be why I wasn't reaching full power or rpm originally as well?

[Merc 2.5]

Yes. I believe a few guys got them bad out of the package!! Good ignition parts is always $well spent imo

[Rider_560]

DVA came in today. I believe my multimeter is too cheap. Only one the auto parts store had. $20. Going to borrow one from work tomorrow an retest. My numbers were jumping around probably +/- 15v or so. All values were still in spec, Except my coil values were low.

But my dva numbers were also jumping around.

First question is... stator ohms out of spec but dva readings seem fine. If it passes dva, is it good? Or does it need to pass both.

Stator tests...

Test 1 then 2 ohm...
(Color to ground, CDI spec 5000-7000 ohms)

Blue to ground (1)4480 (2)6360

Blue/white to ground (1)4220 (2)4050

Red to ground (spec 90-160) test (1)123 (2)120

Red/white (spec 90-160) test (1)122 (2)119

Ohm test color to color (spec 3500-4200 ohms)

Red/white to blue/white (bouncing between) 5000-6000

Red to blue (bouncing between) 4000-4500

DVA readings @ 1000rpm test 1 then test 2...

Blue to ground (spec 195v-265v) test (1)230v (2)226v

Blue/white to ground (spec 195v-265v) test (1)210v (2)220v

Red to ground (spec 120v-160v) test (1)140v (2)150v

Red/white to ground (spec 120v-160v) test (1)140v (2)160v

DVA readings @ 3000rpm test 1 then test 2

Blue to ground (spec 255v-345v) test (1)300v (2)330v

Blue/white to ground (spec 255v-345v) test (1)310v (2)320v

Red to ground (spec 230v-320v) test (1)280v (2)295

Red/white to ground (spec 230v-320v) test (1)300v (2)300v

Trigger

Trigger ohmed within spec and all values were very similar. Also had approx. 40 volt while running between every lead and ground. Spec was 4+ volts

So what do you guys think. Stator is good and it is the switch boxes? I am ordering switch boxes tonight and I just don't want to ruin the new ones.

Thanks!

[Rider_560]

Re-did dva this evening with a fluke multimeter. First tests at 1k rpm. All measurements were in spec except stator dva test blue to ground. The volts on 2 coil were low, at first. Same 2 I was having firing issues with before. The volts on cylinder 1 and 5 (started as 2 and 6 then move switch box and firing problem moved with it) were low, around 1.5v, coil 3 was in the 200s (spec 125-175). The dva reading on the blue wire to ground was 295 (spec 195v-265v). Then I revved the engine a couple times (before spark was weak on 1 and 5, revved the engine, back to neutral. Spark then jumped 7/16" gap). Then re-did the dva readings on the coils 145v on all 6. Re-did dva reading on blue to ground, it was 210 (spec 195v-265v). I then checked all circuits at 3000rpm. All were within spec. I then rechecked values at 1000 rpm. All within spec.

I believe the short circuit in the bad switchbox is causing high voltage in the stator and low voltage to the coil. When revved and the short clears, voltage returns to normal at coils and stator. Would this be a plausible assumption? Is my stator likely bad? I have 2 switchboxes arriving tomorrow and don't want to ruin them. I don't mind buying a stator, I just don't think it's bad. I'm going to redo all DVA tests tommorow after the new switchboxes are installed. Would the testing procedure be enough time to ruin the boxes?

Thanks for any help in advance.

[Merc 2.5]

I understand ur concern 100% but I dont wanna say one way or the other but in past experiences when I had a bad box it didntnhurt stator or Visa versa , i would put new boxes on and check fire before you start the engine, sounds like if it sits it wont fire but will when warm,,so theoretically if it fires with new boxes cold,you should be safe to run , if acts same gonna b stator. I'm pretty positive you got the fix on the way, install,test,run, if you fry boxes by testing then I'd have to say you hooked something up wrong

[Rider_560]

Need some help please!! First time using DVA. DVA is attached to fluke multimeter.

I redid readings today immediately after installing new CDI electronics switchboxes. Revved motor to 1k rpm. I'm going off of my tach, not sure how accurate it is. Volts on red and red/white stator leads were low, 95-100v on red and 110v on red/white. Spec is 120v-160v. Blues were in spec. I cut the boat off. Literally for Less than 1 minute. To walk to the truck (attached to the boat) to grab a pen and write down readings. I cranked the boat back up. Never revved it or anything. Slowly revved back to 1k rpm. Specs were then 135v on red, 130v on red/white (spec 120v-160v). Blue checked 205v, blue/white 195v (spec 195v-265v).

I then revved to 3k rpm, to check those specs. 268v on blue, 275v on blue/white (spec 255v-345v). 270v on red, 268v on red/white (spec 230v-320v). I was going to cool and recheck but ran out of gas.

My stator may be bad but I'm not 100% convinced. I had 138v-145v at all 6 coils the whole time. Spec is 125v-175v. What do you guys think, is my stator good to run?

[Rider_560]

Again, I'm not sure how accurate rpm tach on dash is. All were in spec on second start up. Motor was no warmer or cooler for second startup.

[Merc 2.5]

Do you have a extra stator to try?

[Rider_560]

I dont

[Rider_560]

I was going to recheck tomorrow when I get more gas. Based on that, would you consider my stator bad?

[Merc 2.5]

Can u send me a pic of yours?

[Merc 2.5]

Based on ur readings it was out of spec but let me ask. Did boxes fix firing issue?