75 Mariner 3 cyl Still no spark.

I have an 89 Mariner 75 3 cyl (ser #OC170850) which died suddenly at the end of the season last year after running flawlessly. I've found that no spark was present at all 3 cylinders. I found that one of the trigger leads (white) was completely disintegrated. Replaced trigger with brand new one. Still no spark at no cylinders. I isolated out the mercury tilt switch/harness/ and regulator and this makes no difference. The stator (red stator upgrade) ohms out at 675 (range 500-700). My question is: could the broken trigger have taken out the switch box?? could the stator or the black adaptor attached be at fault causing the no spark condition even though the stator ohms o.k. Do I need to retime if I replace a trigger or would this even cause a no spark condition if timing is off? Would a burned out switch box cause no sparks if everything is o.k. I'm stumped at this point. The rusted out lead on the trigger looked like the only problem, but I guess there is more...

Any advice is greatly appreciated. This ignition system seems to be problematic in these old Merc/ mariners..

Re: 75 Mariner 3 cyl Still no spark.

I have an 86 Merc75 and I had the same kind of wire disintegration as you described. I replaced the stator and trigger as well. I had no spark on number three (it's a four cylinder). Turned out to be the switchbox. From what I read, yes failures of the other parts in the electrical ignition system can kill the switchbox and it is not uncommon to replace all of them when something goes wrong. On the bright side, the aftermarket parts from CDI and the like are of higher quality than the original Merc parts and should last longer. Good luck.

Re: 75 Mariner 3 cyl Still no spark.

What made you replace the stator if you only noted the trigger problem? I am strongly thinking my trigger took out the switchbox, hence I ordered the CDI switchbox. This one is plastic vs. the factory oem metal one ?less chance of arcing. Anyone else have a damaged trigger take out a switchbox?

Re: 75 Mariner 3 cyl Still no spark.

Switchbox was the problem. I guess that broken trigger leads can take out a switchbox, or maybe it was just a coincidence. It seems a lot of people are having the white wire on the trigger completely disintegrate...Glad I replaced all my mercury parts with CDI/ Rapair--seem much better made..jeff.

Re: 75 Mariner 3 cyl Still no spark.

I have a similar problem on a 80 hp 3 cyl Merc, 1988. When i first bought it i had no charging. The rectifier was bad so i replaced. It charges now ok. I had a on and off again problem with the lower cylinder not fireing. I found the white/ black wire on the trigger to be frayed and the insulation partly missing. I resolderd on new end and used some heat shrink tubeing. This did not help, and i didnt think it will becasue there was still enough wire makeing a circuit before i repaired it. I determined that the switch box was bad. I had voltage from stator and trigger. I repalced switch box with a new cdi one and it ran very well, with only a small hesitation on hevy excelleration from low end. Thought i had problem solved and felt that the hesitation was maybe fuel or altitude related. The problem has gotten worse now after a few trips. ON the latest trip the boat will slow down and even die when trying to plane, or die after getting going . It will restart instantly and run ok at fast idle speed. Then the problem will go away and it runs ok again for a while. I tryed squezing the fuel bulb when this going on and it didnt help at all. Seemed to make it worse once. Im waiting on a Dva meter i ordered and am in limbo now. But trigger and stator ohm out good. I even tryed it with the engine warm an d no difference. Im not sure but i dont think its fuel? Any ideas or thoughts? I have been leaning toward the stator but the frayed wire on trigger has me rethinking that. Im 99% sure that the old switch box was bad. Maybe trigger can cause that? And i hope i have not damaged the new cdi switch box again ? Any ideas? Thanks joe

Re: 75 Mariner 3 cyl Still no spark.

Do not rule the fuel pump and fuel line, check the lines from the tank all the way to the carbs for leaks, the smallest amount of air leaking in causes some of the most frustrations, also change out the fuel filter.

Re: 75 Mariner 3 cyl Still no spark.

Which stator do you have on your 88 merc 3 cyl? Are you up to the red stator yet or has it been replaced with the CDI/rapair?? My red stator ohm'd out o.k but was bad anyhow, could have been the adaptor (long black enclosed box) that was bad. The CDI stator does away with this thing--less chance for problems..good luck.

Re: 75 Mariner 3 cyl Still no spark.

Im not sure which stator i have. I have not taken the flywheel off yet to look at it. Is there away to tell without pulling flywheel off? I was waiting to try dva testing before i take it off. Judgeing by the engine and the friends i got the boat from its probably old merc stuff. The switchbox was an old merc one. Where whould the long black enclossed box be if i have that on mine, under flywheel im guessing? Also, the fuel line and bubble are replaced only a year ago, as was the fuel filter. I will check that again and i bought a fuel pump repair kit. Somebody suggested reduing the fuel pump on a motor that sat for awhile. Thanks and feel free to add an more info. Joe

Re: 75 Mariner 3 cyl Still no spark.

You should be able to tell which stator you have w/o taking the flywheel off. If its maroon/ red, you have the newer red stator and likely the adaptor (which hangs down from the stator, might be sitting next to or behind the starter). If you have a black stator, you won't have an adaptor..plus you likely found your problem. Taking the flywheel is a cinch with the flywheel removal tool that threads in and a buddy to hold the flywheel to prevent it from rotating.

Re: 75 Mariner 3 cyl Still no spark.

Thanks for the help. W/O takeing the flywheel off it looks like i hava a black stator. All black as far as i can see. Still waiting on new dva adaptor to test before i remove flywheel or parts. I did replace plug wires, just becasue they look old. I didnt notice any change when running it on the ears here at home, havent gone to lake again. While i dont think its the problem i have noticed some corrision, green color inside the coil where the plug wires hook. I have cleaned them some but very hard to clean out all. It looks like maybe there was some knid of electrical greese in there at one time? Im thinking about replacing them becasue it seeems very tough to really clean that out. I dont think thats my problem though as it was running well with that berfore. Still thinking stator but i guess i m at the point where id like to really learn what im doing. Thanks joe

Re: 75 Mariner 3 cyl Still no spark.

If the stator is black, you likely still have the original stator (impressive).. But that is where your problem probably lies. The black stator has low speed windings and high speed windings. Your low speed sound o.k. but once you get it on plane (high speed windings) you notice your problems. Time to replace the whole stator. Doubt it is the coils, they almost never go bad. Get a 15/16" inch hex socket, flywheel removal tool and pull it off, order the CDI stator, and you'll likely be on your way. While you have the wheel off, check the trigger wires. Pulling the flywheel, installing a new stator, and replacing the flywheel is an hour job if you are taking your time. DOn't forget to put loctite on the 4 allen bolts in the stator or the stator could lift out and get destroyed by the heavy flywheel. Also remember the orientation of the old stator before you take it off (better yet- take a digital pic) jeff

Re: 75 Mariner 3 cyl Still no spark.

Thanks for the advice Jeff. I didnt get a chance to work on boat today but will keep you updated. Still frustrated that my dva tester did not arrive yet. But i agree with you, i have suspected the stator all along. It seems that this is a know Merc Problem? I guess every motor, car, or anything has its known to fail part! I have a flywheel puller that i used on my 4.5 hp Merc that should work for that. And will get socket here soon. I guess then i can get a better look at the Trigger wires? I had some frayed strands and the insulation was broken near the end that hooks to switchbox. And im assueming that the new stators from cdi hook up the same?
BY the way, you have good taste in boats! I have been a Whaler man for along time now! Never have trouble with them, just the engines! I will keep you udated. THanks Joe

Re: 75 Mariner 3 cyl Still no spark.

I'm going to take a guess it was either the white trigger wire or white/black one.. If you see fraying insulation at the switchbox I can only imagine what it must look like coming off the trigger under the flywheel. My trigger wire became green mush and finally fell completely apart.

I would be surprised if a puller for a 4.5hp motor would work for yours, so you'll have to take a look. i found the socket at Ace Hardware for under 10 bucks. CDI parts come with detailed and user friendly instructions. No modifications necessary if you don't have the red stator w/ adaptor. I ordered a whole new ignition system (reg/stator/switchbox) from boatfix.net/com- best prices and quick shipping.. i compare every possible price before committing and they came out by far the cheapest ($398 vs. around 700 retail).. jeff.

Re: 75 Mariner 3 cyl Still no spark.

if you do need a new stator use:

CDI parts- stators can be confusing w/ mercs. These are your options, keep in mind you'll need a regulator if you don't have one.

174-8778K1 (9 amp) or

174-9710K1 (16 amp)

Re: 75 Mariner 3 cyl Still no spark.

Jeff, i appreciate all the input. Im a pretty good at gearhead stuff, but not an expert. I m a electrician maintence guy at a newspaper and have done same in a steel mill. I guess i suffer from wanting to really understand what is going on with how it works. I am learning here! Funny but i have had very good luck with two smaller Mercs over the years but not so great on two midsize models.
Anyway, the white/black trigger wire had some corrison,strands missing and the insulation broke down on the switch box end. Sounds like anothere common problem? Probably makes sense to replace that too, especially if the wire looks bad when i get flywheel off. I agree that boatfix is good, i bought switch box from them last year.
Also, did you have to reset your timing when you changed all this? For some reason the idea of setting timing and sink of carbs looks very scary to me! Id think it will not change by replacing the stator.
Take care and i will keep you informed here. Thanks Joe

Re: 75 Mariner 3 cyl Still no spark.

Just get a permanent marker and mark the flywheel, maybe line it up with the starter, put in back in the same way (line up the key in the underside of the flywheel). ** clean all grease off the crankshaft before re-installing the flywheel- torque down to 120 ft/lbs- or all your strength possible. I didn't need to adjust timing, this won't change carbs/ link/sync, etc.

Re: 75 Mariner 3 cyl Still no spark.

Well my d va tester finally arrived so im going to play with that now! Where did you buy your trigger? It seems hard to find one for my application? I will keep you posted here. Might just replace both if the wireing is bad. I will keep you informed here .

Re: 75 Mariner 3 cyl Still no spark.

Bought the trigger on Mercurypartsexpress.com (Cape Marine- Bourne, Mass). Just enter your engine serial number and go under the flywheel section...

Re: 75 Mariner 3 cyl Still no spark.

Well i did some dva tests and i think its the trigger. Seems like the trigger voltage is lower than the specs. Still have to relook at that. Funny, but the engine seems to be running worse as im trying to work on it. But nothing clear cut jumps out as the problem. Stator seems ok. Ran into another small problem. I dont have the right flywheel puller. I thought this motor was going to have threads in middle to use puller with bolts but it doesnt. My 4 hp does. Im going to have to find some puller with 3 ways jaws to reach lip on side. Doesnt seem any other way to do it. I think i can borrow one. Beging to get tired of this! I wont quit my day job.

Re: 75 Mariner 3 cyl Still no spark.

Well i ordered new trigger and stator today. The stator seemed ok but since i have to get inside to change trigger i figure ill just change it too. The dva test were interesting but not totally conclusive like i was hopeing. I believe i had low voltage on the trigger wires and as i said before the white/blk wire was correded near the switch box. Dont know really what else to try. Now i got to wait for parts.