Motor stall beyond 3000 rpm-cuts out

[BuilderFL]

1989 Mercury Black Max 200 HP
I would take the boat out and I could get on plane with no problems, but after a while, the motor would bog out, and loose power, it would run about 9 mph and turn 2500 rpm. There will be times that after 5-10 minutes later, the motor will kick in and start running great. Then it would loose power again and if I push beyond 3000 rpm, it would stall and just cuts out, however it's fine if I run at lower rpm.
Any suggestions as to the problem?
Thanks! :sad:

[phatdaddy]

intermitent loss of fire on 3 cyl. one of the power packs going bad? is the fuel ball hard when it is bogging?

[spareparts]

sounds like a switch box, but could be the high speed windings in the stator, you;ll need to check it with a DVA meter and this http://issuu.com/cdielectronics/docs/troubleshootingguide?mode=embed&layout=http%3A%2F%2Fskin.issuu.com%2Fv%2Fcolor%2Fl ayout.xml&backgroundColor=000000&showFlipBtn=true

[BuilderFL]

I just ordered a DVA adpter (ESP640) this morning thinking I was going to need it. I'll check the switch boxes today.
Thanks guys! :beer:

[THEFERMANATOR]

This sounds like the stator to me, but could be a switch box.

[phatdaddy]

builder, do you have a volt gauge on your dash or electronics? is it reading above 13 vlts when running?

[BuilderFL]

Yes its closer to 13.6vdc and its coming from my furuno fish finder. On the voltmeter it's harder to tell, but its over the 12 volts

[phatdaddy]

ok. some times when you have stator issues, the charging system or the tach will act up.

[lathehand]

If it were me I';d be looking to change the stator

[BuilderFL]

phatdaddy, now that you mention the tachometer, I have been getting readings high in the 7k rpms at full throttle and was concerned. But then I connected an external tachometer and the readings were within normal parameters. Just thought I had a bad tachometer. Your think it may be tied to the stator?

[phatdaddy]

that would make me think stator then. does that motor have the 40 amp charging system?

[BuilderFL]

Well got my DVA delivered (tooldiscounter.com) and all tests came in within the CDI parameters. However, I noticed that my lower carburetor was leaking lots of fuel...a stuck float that was cleaned and fixed. Also noticed that there was a water leak coming from behind the middle coils; a hole in the exhaust manifold cover. Took that out, will probably repair from the inside with JB Weld and when I get the gaskets and install them, will test it and keep you informed.
Do you think any of these problems could have cause the original symptoms as reported or just other stuff that needed attention?

[spareparts]

what did the high speed switch box outputs look like. Remember to disconnect the bias wire between the switch boxes when testing out puts(white/black wire) make sure the grounds on all the coils are nice and clean.

[BuilderFL]

Spare, it will be about two weeks before I can get to them. Will be working in San Francisco and then Albuquerque, but I did not remove the bias wire between the switch boxes. Maybe the reason for both to have similar readings.

[BuilderFL]

spare, disconnected the bias wire between the switch boxes (BTW this is a 16 amp flywheel) and these are the max readings to ground with the DVA:
blue=269v
blue/white=284v
red=198v
red/white=177v
What do you think?

[phatdaddy]

builder, i might have one of the older stators. it was a spare i had for my 84 150, but my "new" 94 has the 40 amp. its yours if you need it & i can find it. let me know.

[spareparts]

per CDi your low speed is OK and your high speed is way high
http://www.cdielectronics.com/downloads/Mercury_DVA.pdf

[BuilderFL]

phatdaddy, I would absolutely will take it let me now if you find it. :nice:

[BuilderFL]

Spare, so what does the high speed being way high indicates? A bad stator?

[spareparts]

kinda odd to have something way high, usually it will be low, are you taking the measurements at cranking speed?

[phatdaddy]

builder, i might have misspoke, i just looked through my shed and cannot find my spares. i had a 3 gallon laundry detergent bucket with spare stators & switchboxes that i can't seem to locate. i will look some more and check with a friend that was looking for a switchbox, i might have left it at his house. i will let you know tomorrow night. i HATE it when i know i have/had something and can't find it.

[BuilderFL]

No, Im taking them at idle running speep, at about 900-1000rpm.

[THEFERMANATOR]

No, Im taking them at idle running speep, at about 900-1000rpm.


All measurements are meant to be done at cranking speed with the stator unhooked I believe. I know on OMC's you have to unhook the stator to check it properly, and you need about 200-250 cranking RPM's.

[phatdaddy]

had a rain day today, so i was able to do a more through search. this is the stator i have, i believe it is from the 16 amp system. if you need it , just pm me your address and i will get it in the mail to you

http://i377.photobucket.com/albums/oo214/gls216/IMG_20130205_1639111_zpsf1947ebd.jpg

http://i377.photobucket.com/albums/oo214/gls216/IMG_20130205_163926_zps19b04d4c.jpg

[BuilderFL]

phatdaddy, thats great! But if you dont mind, I would like to hold off until I've deterimine correctly that the stator is the problem. THEFERM is now saying that he thinks that the readings should be taken cranking and not running like I did. I will be back home this weekend and will check again. Again thanks!

[BuilderFL]

I got this other link to use as my guide. Gives both test modes
http://www.outboardignition.com/support/174-5456-16.pdf
Will check again this weekend when Im back home.

[spareparts]

its hard to do a running test with out the engine being loaded, you would have to use a test wheel, a dyno, or hang off the back of the boat while some one is driving. I usually just check it at cranking speed, pull the plugs out, set up a spark board and spin it over, it will usually show up

[BuilderFL]

OK, I will retest at cranking and check the readings. Thanks!

[BuilderFL]

Ok guys, with the bias wire between the switch boxes disconnected (BTW this is a 16 amp flywheel) and plugs out, these are the new max readings to ground with the DVA:

blue=217v
blue/white=222v
red=53v
red/white=53v

Trigger check
wire read to / resistance / dva connected / dva disconnected
brown white 1248 / 5.26 / 5.20
white purple 1268 / 4.81 / 5.77
purple brown 0 / 1.52 / 4.56

According to Mercury CDI trouble shooting, since the readings are within specs when disconnected, the trigger is good and the pack(s) are bad.
What do you think?

[spareparts]

sounds like a switch box, if you replace one and its better, go ahead and replace the otehr one, it won't be long before it takes a dump as well
what was the outputs on the green wires?

[BuilderFL]

Spare, did not check the green wire. Didnt see it in the troubleshooting or just missed it. Will do tomorrow and report back.

[spareparts]

green wires, they are the outputs from the switch boxes to the coils, that should tell you the output voltage

[BuilderFL]

Had a chance to take the boat out yesterday and the motor performed perfectly. I had some spare power packs that I had gotten from bigshrimping back in 2007 and I replaced both of them, even though only one was testing bad. Problem solved!
Thanks Guys :beer:

[phatdaddy]

great news, love it when something on a boat finally gets fixed.

if you want to,pm me your address and i'll send you that stator, won't fit anything i own, you might get some use out of it.

[phatdaddy]

builder, shipped the stator today. i put it in the hands of the federal govt., hope you at least get some of it by wed or thurs.

[BuilderFL]

Phatdaddy, Will let you know when I get it. Thanks! :clap:

[BuilderFL]

George, Got the stator in today's mail. Thanks for your time, effort and the expense of shipping it. You're the man! :beer:

[phatdaddy]

wow, that was quick. no problem, hope you never need it.