1991 Mariner Mag II low oil rev limiter?

[Knothead]

We have acquired a 91 Mag II that hasn't been run in years (actually hasn't been run much in it's whole life). I had the carbs rebuilt & took the oil injection off. I did not take the low oil module completely off....just unhooked the tan w/blue wire from the module to keep it from sending a signal to the beeper. Took it to the lake yesterday & it cranks easily, but runs terribly. Has a steady miss & seems to be flooding. Would only turn around 3200 rpm. Does this motor have a rev limiter associated with the low oil module? Should I go ahead & unhook the green wire & white wire & completely remove the module?

Thanks,
David

[toyomirage02]

yes take it all the way off,along with the black box on either the side or top off the port side of the mota u dont need it,it also controlls the shift interrupt that ya dont need or you may not have

[Knothead]

I went over last night & disconnected the purple power wire & green wire to the switch box, then took the module completely off the motor. Cranked it on the hose, & it still runs like there's a rev limiter on (which I understood these motors don't have). Also, while revving it to 3000 rpm's a couple of times, the tach started jumping around & lights in gauges started flickering (getting brighter when I'd rev it). I'm thinking stator and/or regulator may be bad.

[pyro]

Usually a motor that won't turn over 3000 rpm has a cooked stator. You need a meter with a DVA adapter to test it-- A bad one won't always show up in a simple ohm test.

[Knothead]

Usually a motor that won't turn over 3000 rpm has a cooked stator. You need a meter with a DVA adapter to test it-- A bad one won't always show up in a simple ohm test.

It will actually rev up to @ 4000 while in neutral, but would only turn 3200 while driving the boat. I did not see the tach doing the "jumping around" while running the boat at the lake, but it started doing it last night on the hose. It also sounded just like a "ricer" car or bike motor at the rev limiter when I held it at 3000 rpm for a couple of seconds.....you know, the "ying..ying..ying.." sound.....

I'll find someone with the adapter to hook it up. I'm thinking the stator is fried.....

Thanks!

[CharlieB53]

The stator has three sets of windings, battery charging, low speed ignition, and high speed ignition.

Unfortunately rev'ing in Neutral won't tell you anything about the ignition as the low speed windings make sufficient voltage you could rev high enough to throw the rods out the side before you made enough load to require the high speed windings to generate voltage.

A DVA Meter or a DVA adaptor for any Volt/Ohm meter is necessary to properly test the stator.

Another possible fault is a bad rectifier/regulator causing the EMT in the stator to impact the high speed windings magnetic field and reduce voltage.

Disconnect both yellow wires from the stator to the Rect/reg and retest motor performance, if it runs fine then order a new rect/reg. If not, get a DVA meter or adaptor.

Always remember, there is NO RETURN on electrical parts, test twice, order once.

[Knothead]

The stator has three sets of windings, battery charging, low speed ignition, and high speed ignition.

Unfortunately rev'ing in Neutral won't tell you anything about the ignition as the low speed windings make sufficient voltage you could rev high enough to throw the rods out the side before you made enough load to require the high speed windings to generate voltage.

A DVA Meter or a DVA adaptor for any Volt/Ohm meter is necessary to properly test the stator.

Another possible fault is a bad rectifier/regulator causing the EMT in the stator to impact the high speed windings magnetic field and reduce voltage.

Disconnect both yellow wires from the stator to the Rect/reg and retest motor performance, if it runs fine then order a new rect/reg. If not, get a DVA meter or adaptor.

Always remember, there is NO RETURN on electrical parts, test twice, order once.

I had a local guy also tell me that the reg/rectifier COULD cause my symptoms, so I'll try unhooking the yellow wires this evening & see how it runs! Thanks for the advice!

[Knothead]

Just unhooked the yellow wires from reg/rec & no change whatsoever, except that tach wouldn't register at all. Sounds like stator time…

[CharlieB53]

DVA test the stator AND the triggers.

A broken trigger wire can abut and still fire the cyl until the timing lever moves the wire far enough the ends come apart and the cyl doesn't fire.

There again that NO RETURN thing makes it very important to TEST AND PROVE which parts is at fault.

The high side of the stator usaully will not allow a motor under load to turn 2200 - 2600, the fact you can get to 3200 underway tells me you need to check into things farther.

A failing fuel pump, restricted fuel hose from the lining dying, sloughing off and clogging the hose, air sucking into the fuel system not allowing the fuel pump to move enough fuel to feed the motor, dirty jets.

I'd look at a lot more before starting to toss money and parts at your motor.

A simple DVA test of the stator will determine its health, then you can move on to find the real problem. And save a few (a lot) bucks.

[Knothead]

DVA test the stator AND the triggers.

A broken trigger wire can abut and still fire the cyl until the timing lever moves the wire far enough the ends come apart and the cyl doesn't fire.

There again that NO RETURN thing makes it very important to TEST AND PROVE which parts is at fault.

The high side of the stator usaully will not allow a motor under load to turn 2200 - 2600, the fact you can get to 3200 underway tells me you need to check into things farther.

A failing fuel pump, restricted fuel hose from the lining dying, sloughing off and clogging the hose, air sucking into the fuel system not allowing the fuel pump to move enough fuel to feed the motor, dirty jets.

I'd look at a lot more before starting to toss money and parts at your motor.

A simple DVA test of the stator will determine its health, then you can move on to find the real problem. And save a few (a lot) bucks.

Thanks for the excellent advice! I know the fuel line is new "ethanol proof" blue hose, carbs have been gone through with new kits in each, & fuel pump, too.....

It seems to be flooding (not burning all the fuel), which is why I suspect firing problems. Exhaust area (prop) is turning black & nasty quickly....I'm going to try to test the stator & trigger this afternoon. I think my meter is a DVM meter. If not I'll go by Radio Shack & pick up the resistors & diodes to build an adapter.

I'll report back what I find out......

Again....Thanks!

[pyro]

Does this motor have a pulse/prime fuel pump on the block? If the diaphragm inside fails, it will puke fuel into the crankcase and give you a rich condition. It would still probably clear out after a few seconds of throttle and smoke though.

Not every ignition set jumps from the low to the high side at the same exact RPM. This still sounds like a bad stator to me.

The trigger should have the same resistance between each of the three wires in each switchbox set. Move the timing arm fully back and forth while testing each leg of each trigger set. Remember, like was already mentioned, resistance tests are not reliable. A meter with a DVA adaptor on a motor under load is the only truly reliable test method. For example... My trigger reads about 25K across each delta leg, which oddly enough is about four times higher than the resistance value should actually read, but is still works just fine.

[everyoneknowsjeff]

Hello - I am having a issue similar to this tread - I have what is labeled as a Mariner Magnum II 150 but it has a Mercury head on it and different carbs. From coming out of water to going back in, it developed a problem of not wanting to come out of low RPS and out of the hole. It idles fine in neutral and will run great when out of water on hose in and out of gear - But put it in the water and into gear it will only do about 1500 RPS and not come up. Back to neutral and will rev all the way. Had carbs supposedly rebuilt and he claims to have done a tune up but went to water yesterday and same thing. Cranks and idles great but wont run in gear up to speed.

Is this simular to your problem? or does any one have ideas of what do do now. On a tight budget and guy took $500 to do carbs and tune up already with no result (oh and he cleaned fuel tanks and checked compression and stated they are fine).

[props'n'rocks]

Sounds to me like you have a bad diaphragm in the fuel pump..pull it apart and check to make sure it's not all cracked and brittle..let me know!

[everyoneknowsjeff]

I recently rebuilt the fuel pump with a kit. It is the first time ive done such, but was pretty straight forward and felt like it was done right - Should I re check it?

[props'n'rocks]

If you already did it,,you did it..it's pretty basic, carbs are filling up, bulb goes tight right?