94 OMC 115 stator or rectifier going out?

Ever since I bought this thing I've had a problem at WOT. After about 5 minutes it immediately cuts from 5200 RPM to 4700 RPM and won't run higher for the rest of the day, except for occasional bursts up to 5200 RPM.<br /><br />I thought it was a fuel problem at first and completely reworked the fuel system all the way from gas pickup to carbs. It runs a little smoother now but still has the problem at WOT.<br /><br />I am convinced it is the ignition system. A weird thing happened the last two times I was out. The tach sputtered and then quit. It will occasionally come back on, but it is really sporadic.<br /><br />One thing I did on the engine --- I rerouted the charging harness (back to the correct way). This required unscrewing the terminal strip. Well, my idiot self didn't disconnect the battery. At least one wire, from the engine harness, sparked on the block. I guessed that since ignition was off, it was a wire straight from the battery and wouldn't cause a problem. Am I right?<br /><br />Anyway, with the problems in both the tach circuit and in the ignition, I am thinking the stator is going bad. Does this sound right? Does it sound like I burned up the rectifier also? Could it be the power pack?<br /><br />I am going to do some resistance checks on the rectifier tomorrow. Does anyone have any other electrical tests, with the boat out of water, that they recommened? Anything I should know?<br /><br />Thanks in advance!

Re: 94 OMC 115 stator or rectifier going out?

HI CRAZYJ, I BELIEVE YOUR RECTIFIER IS BAD IN YOUR MOTOR. I HAVE A PAIR OF THESE MOTORS & YOUR PROBLEM SOUNDS JUST LIKE MINE. I WOULD CHECK THE BATTERY VOLTAGE, BEFORE STARTING & MOTOR RUNNING. IF THE RECTIFIER IS BAD THE TACH WILL STOP WORKING & YOUR MOTOR WILL START ACTING UP BECAUSE OF VOLTAGE PROBLEMS FROM THE BATTERY. THE VOLTAGE AT THE BATTERY WILL GIVE YOU THE ANSWER YOU ARE LOOKING FOR. THATS WHERE I WOULD START. HOPE THIS HELPS. (DIRTPOORE96)

Re: 94 OMC 115 stator or rectifier going out?

So a bad rectifier can cause ignition problems in addition to charging and tach problems? It was my understanding that the rectifier was only for the charging circuit.<br /><br />Also to add, I have checked spark with induction timing light at idle before and after the problem. At idle it seems I am getting a consistent spark at all cylinders. I haven't checked spark at WOT.

Re: 94 OMC 115 stator or rectifier going out?

HI CRAZYJ, THE RECTIFIER IS FOR THE CHARGING THE BATTERIES. WHAT HAPPENS IS THE REC STOPS THE CURRENT GOING TO THE BATTERY & THE BATTERY VOLTAGE STARTS TO DROP SLOWLY. THIS DROPS THE TACH, IGNITION PROBLEMS & WILL ALSO SET YOUR ALARMS OFF. HAVE YOU CHECKED YOUR VOLTAGE AT THE BATTERY? (SITTING-RUNNING) THESE RECTIFIERS ARE IMPOSSIBLE TO FIX. IF 1 OF THE 4 DIODES BURNS OUT THEY DO NOT WORK. I THINK I PAID ABOUT $189.00 FOR 1 ONE THE NET.

Re: 94 OMC 115 stator or rectifier going out?

Cj, just replaced the rectifier in my J200. Symptoms were tach acting flakey, battery not charging and odd readings on my voltmeter. Unfortunately, when mine went, it put a short to ground on the battery. Ruined the battery and charred up a bunch of wiring.<br /> <br />It's not to hard to replace but be sure you tag all of the wires and connectors. I got fooled because they used plain orange wire on the power pack side of two connectors. I only checked the wiring harness side for the color coding. Didn't notice till I was putting it back together. There were a few anxious moments when I first cranked it.

Re: 94 OMC 115 stator or rectifier going out?

If a shorted rectifier effects the ignition system it's because of the magnetic flux it can set up under the flywheel.<br /><br />c/6<br /><br />Hooty

Re: 94 OMC 115 stator or rectifier going out?

Is it likely that it is affecting ignition with the mag flux? Does a rectifier typically do this when going bad?<br /><br />I will be doing resistance checks tomorrow on the rectifier.<br /><br />I took the boat out today and got a little more read off of it. For one, the voltmeter on the dash doesn't indicate the battery is getting a charge. It reads the exact same whether engine is on or off, hot or cold. Also, the tachometer quitting coincides exactly with the time the engine loses power after about 5 minutes. The tach needle goes limp and fluctuates for about 15 secs, then dies. So here are the symptoms:<br /><br />- battery never charging<br />- ignition weakens after 5 minutes, rpms drop from 5200 to 4700<br />- tach goes out after 5 minutes, with ignition<br /><br />I am starting to think rectifier also, but still have in mind stator. Are these also not the symptoms of a bad stator?<br /><br />Thanks guys! I know I am being a bit hesitant, I just hate throwing money at parts before I can isolate the problem.

Re: 94 OMC 115 stator or rectifier going out?

HEY CRAZYJ, YOU ARE NARROWING IT DOWN VERY QUICKLY. THE ONLY PART BETWEEN THE BATTERY & THE STATOR IS THE RECTIFIER. DOES THAT GIVE YOU YOUR ANSWER. PULL THE REC. OFF THE MOTOR & DO AN OHM'S TEST ON THE DIODES. IF YOU HAVE A MANUAL, YOU CAN DO THIS TEST EASILY WITH AN OHM METER. IF NOT, LET ME KNOW & I CAN GET YOU THE INSTRUCTIONS.

Re: 94 OMC 115 stator or rectifier going out?

CJ, be cautious. To me it sounds like you rectifier is dying a slow death. Sooner or later, one of the diodes will go and chances are you will have a dead short to ground. This will provide a direct path from your battery to ground, the equivalent of connecting the two battery terminals with a peice of wire. If this happens, all you can do is tune for minimum smoke.<br />I was lucky, my battery was almost dead (due to the rectifier not working) when the short occurred. All I did was melt some of the protective nylon sleeves around the rectivier/power pack. If the battery had been fully charged, I probably would be selling the entire rig to the insurance company.

Re: 94 OMC 115 stator or rectifier going out?

Thanks guys, my multimeter should be in my mailbox today!<br /><br />Is it possible to totally disconnect the rectifier while running to see if it is the culprit of the ignition system problems also?

Re: 94 OMC 115 stator or rectifier going out?

HI CRAZYJ, YES IT IS POSSIBLE TO DISCONNECT THE RECTIFER. DISCONNECT THE RED WIRE FROM THE SIDE OF THE MOTOR WHERE THE MAIN RED CABLE FROM THE BATTERY IS CONNECTED. DO NOT REMOVE THE RECTIFIER FROM THE BLOCK & START, YOU WILL PUMP WATER ALL OVER THE ENGINE. THE REC. IS WATER COOLED FROM THE WATER PUMP.

Re: 94 OMC 115 stator or rectifier going out?

Welp, just got back from the lake and I am still getting same rpm problems, even after disconnecting the rectifier.<br /><br />This time it started good at high rpms but it only lasted for about one minute, rather than the 5 minutes it had before. There were several times on the lake where for about 1-2 minutes, it would start running good, but then drop back down. It seems to be definitely an ignition issue because of the sharp changes. I still am waiting on my multimeter in the mail so that I can test the stator voltage.

Re: 94 OMC 115 stator or rectifier going out?

just got back from the lake (AGAIN!) and found out a little more.<br /><br />The problem with the ignition is from the last cylinder not sparking at all, when hot. I switched the coils with another cylinder and I still get have the problem with the one cylinder. I also switched the plugs, same thing. I forgot to try switching any spark plug wires, coil wires, etc, and can't reproduce it at home in the driveway to test. So it is looking like to me the problem is the power pack. Sound familiar to anyone? Could it be the stator? or anything else?<br /><br />The rectifier seems dead as a door nail. I checked resistance across both yellows to red, both directions.. and nothing. infinite resistance. Is this normal for a bad rectifier to be this dead? or could my multimeter be bad?<br /><br />Across the two yellow stator wires I am reading 20 VAC at idle and 38 VAC at ~2000 RPM. Sound right?<br /><br />Thanks guys for everything! I'm gonna beat this one!

Re: 94 OMC 115 stator or rectifier going out?

HEY CRAZYJ, THE RECTIFIER IS TOASTED. THROUGH IT OUT & GET A NEW ONE BEFORE YOU DO ANYTHING ELSE WITH YOUR MOTOR. ONE OF THE DIODES IS BURNED OUT. THERE ARE 4 DIODES INSIDE THE RECTIFIER & WHEN 1 GOES THEY ALL GO. THE DIODE IS A LITTLE SWITCH THAT OPENS & CLOSES WITH CURRENT. WHEN 1 BURNS OPEN OR CLOSED, THE REC. DOESN'T WORK ANY MORE. PUT A NEW ONE ON & RUN YOUR MOTOR. IT COULD SOLVE ALL OF THE PROBLEMS YOUR HAVING.

Re: 94 OMC 115 stator or rectifier going out?

Trust the multimeter-<br /><br />You have a bad rectifier--sure clue is the tach problem--no ifs about it.<br /><br />DirtPoore96 nailed it on the head a week ago!<br /><br />But it is fun to test all those other things even though it seems to drive us crazy.<br /><br />Good luck

Re: 94 OMC 115 stator or rectifier going out?

The rectifier has been disconnected for a week and I've been swapping batteries back and forth with my dad's boat.<br /><br />I got a new powerpack that fixed the big problem, the ignition. Now I am running on 4 instead of 3 cylinders. What a difference !!! <br /><br />I think the rectifier might have got zapped because of all the running that we did on land. We had it running for 30-40 mins on land to diagnose the ignition issue. We were running water through it, but I'm not convinced it gets supplied enough water to get all the way up to the rectifier.<br /><br />There is another problem we have now though. This is an inboard jet drive. I am getting a LOT of water in the bilge. The bilge pump can keep up, but I have to run it for about 1/3 of the time. Is this normal?<br /><br />Anyway, I'll probably need to do a lot of running on land to diagnose where the water is coming from so I'll probably hold off on installing the rectifier until I get done with that. There was a crack before in the exhast manifold that was supposedly patched. I am guessing they did a half *** job. How much does the engine weigh if we have to take it out?<br /><br />Thanks guys for the help. I'm going to order the rectifier tomorrow.