1985 Mariner 150 sick.

[robroy]

My Mariner 150 has been acting up the last two trips out. Today I decided to tear into it and see if I could find the problem. The motor has dropped off perfomance, will not plane out easily, and lost about 800 rpm at the top end. I started by checking the plugs, the #1 plug, (top right) appeared some what black compared to the others, I hooked up my muffs, and check for spark. No spark on that plug. I then swapped the coil pack input between 1 and 3 packs. Now plug one fires but 3 don't. Not a coil pack problem. I next went back to the switch box (figures...#1 is on the inside switch box) and swap outputs signals between 1 and 3. Now plug 1 fires, but 3 does not. Bad Switch box? I go and get a new switch box, install it, and now all the cylinders off that switch box are not firing. It did seem to work for a short time, but would cut out at any rpm above 3k, but now I have no spark on any plug coming from that switch box. I decide to install the old switch box back in, now all cylinders, including #1 are firing. Do I have one flakey and one bad switch box?

Any help would be greatly appreciated.

 

[robroy]

Re: 1985 Mariner 150 sick.

Well, took the boat into where I purchased the new switch box after about an hour of testing my original switch box, and the new one they came to the conclusion that the switch box they sold me was completely bad, and my switch box was dead on the #1 output. Got yet another new switch box, installed it while there, and now boat fires on all 6 cylinders. Now for the bad, took to boat out for test run on the lake, and now have a totally new problem. The motor sputters and misses when coming up on the gas. It now tops out at 3200rpm and 30mph. Believe it or not, the motor was running much smoother and would achieve better RPM with the old switch box and #1 cylinder not firing. I am perplexed. Could the bad switch box I got from the shop have caused the stator or trigger to go bad? If the stator was bad, wouldn't I lose spark? even at idle? Not sure what a bad trigger would cause.

 

[robroy]

Re: 1985 Mariner 150 sick.

anyone have an idea?

 

[j_martin]

Re: 1985 Mariner 150 sick.

anyone have an idea?

A DVA test of the charge coils of the stator would either find the problem or clear the stator as suspect.

It's hard to beat systematic diagnostics for cost containment.

hope it helps
John

 

[robroy]

Re: 1985 Mariner 150 sick.

I ohmed out the trigger and the stator, and all were in specs, although the stator was on the very high end of specs. hooked everything back up, threw the muffs on and cranked it over. It started, but did not sound good at all. I checked for spark, and now the entire left side was dead. Looks like I toasted yet another switch box. Hmmmm.....this is getting old quick. Went down to the local repair place and bought another new switch box, a new stator, and new trigger. Installed all these parts, and lo and behold I had spark on all 6 cylinders once again. The motor sounded much better than it had in a while also. Off to the river for a water test. The old motor was a little slow out of the hole, but once up on plane, I was able to acheive 60mph and hit 5900rpm. motor sounded smooth, no miss or anything out of the ordinary. Ran up and down the river for about an hour, and it just got better and better. By the end of the trip, the hole shot, speed and RPM were as good as they've ever been. I'm still not sure what the problem was exactaly, but after 3 switch boxes a trigger, and a stator it's back to it's old self. Still not sure why my stator and trigger were reading good, but I suspect one of them was frying switch boxes.

 

[sschefer]

Re: 1985 Mariner 150 sick.

The two most common ways to fry a switch box:

1. Reverse the pos/neg battery cables.
2. Shorted Coil.


Less common:

1. Excessive cranking without plugs and the plugwires not grounded.
2. Unregulated over voltage from stator.

(in your case your stator resitance is on the high side so my guess is that its probably producing slightly lower voltage than spec's. I'm not toatly sure about your stator. I believe there are both a 9amp and a 16 amp verison. The 16amp usually has a voltage regulator while the 9amp doesn't.

I do see a pattern with your problem. It seems everytime you make a switchbox change the problems come and go. If it was me, I would check all the wiring leads from the stator and from the switchbox to the coils. Clean the wires well first then look for one with a cut or bare spot that might be laying against the block or some other part that's bolted to the block. You should also verify that all of your grounds are good and that there are no broken wires at the connectors.

 

[robroy]

Re: 1985 Mariner 150 sick.

I believe my stator is of the 9amp variaty. Like I said before, not sure what was frying the switch boxes, but I now have over two hours of good running motor, witch is about 1hr and 55 minutes more than I've had in the last two weeks. I had checked all the wires for any kind of damage (chaffing, loose connections, or broken wires at the connectors) didn't find any. Basically all the wires except the ones to the coils are now new. If I did have a shorted coil, wouldn't that coil stop firing? Still not sure what was causing the problem, just hope it is gone for good. Now you have me worried I may being looking for another switch box in the near future. I sure hope not.

 

[sschefer]

Re: 1985 Mariner 150 sick.

I believe my stator is of the 9amp variaty. Like I said before, not sure what was frying the switch boxes, but I now have over two hours of good running motor, witch is about 1hr and 55 minutes more than I've had in the last two weeks. I had checked all the wires for any kind of damage (chaffing, loose connections, or broken wires at the connectors) didn't find any. Basically all the wires except the ones to the coils are now new. If I did have a shorted coil, wouldn't that coil stop firing? Still not sure what was causing the problem, just hope it is gone for good. Now you have me worried I may being looking for another switch box in the near future. I sure hope not.

A shorted coil can act real funny, it depends on how badly it's shorted but most of the documentation I've read claim it could damage a switchbox.

Coils are easy enough to check with an ohm meter just make sure they are within spec's both cold and hot. Sometimes what is not shorted when cold can become shorted when hot, (copper wire expansion and contraction). After market coils run about 25-30 dollars each and an annual replacement although not in the tune up books is something I have on my to-do list.

As for your engine running well now. That's fantastic.. Run it till it drops! If the problem pops up again then take my thoughts into consideration otherwise, don't worry about it and have fun!

 

[robroy]

Re: 1985 Mariner 150 sick.

Thanks for the information, I will be checking the coils both cold and hot prior to going back out on the water. Hopefully all is good.