Switchbox killing Stator?

[Grant Brown]

A local marine mechanic told me that if my switchbox is going bad then I am killing my stator. True or False?

Background: 1987 Merc. 70 3 cyl. Good compression, carbs. rebuilt and cleaned 2x, new fuel tank and lines. Stator and rectifier replaced last year, coils checked for resistance - all good. No spun prop.

She starts and idles fine, but won't hole shot at all. Takes forever to get on plane, and tops out at 24 mph. After heat soaking for 10-20 min she fires up and blows out a ton of blue smoke then runs great with amazing hole shot and 33-34 mph all rest of day.

Since everything else is good then the mechanic said it's probably the switchbox. Also said I'd better not run it 'cause I'll kill the stator.

Thanks,
Grant Brown
Vancouver, BC

 

[Laddies]

Re: Switchbox killing Stator?

NO, I don't believe that, if he is sure that a switchbox will fix the problem then if it don't fix it he should remove it on a no charge basis, ask him about that I think we both know what the anwser is. A professional mechanic who relies on a OHM meter to test todays ign. systems is selling parts that about all. You have either a ign. system that is running low voltage, which must be tested with a DVA, which I doubt of a fuel deliver problem the blue smoke indicates that a flooding problem while the engine is at rest, aleaking inlet valve or bad fuel pump diaphram. Did this motor ever preform better on this boat, have you checked the RPM at WOT if it's over proped it will never run right. Anyway there a couple of ideas if we had more info we may be of more help

 

[Grant Brown]

Re: Switchbox killing Stator?

Thanks Laddies,

The boat has always done this. But it was intermittent before (I mean not every time I took it out). One vacation it did it when I first got to the lake then not again all week. Now it's every time. One time it caught full power while running and almost tossed my buddy into the transom.

Seems to me that it's running about 5500 rpm at WOT = about 34mph when it's running good. I don't recall the WOT rpm when it's bad. But it uses a lot of fuel.

Someone suggested a bad plug and that the cyl that wasn't firing was loading up with fuel/oil and then burning off when it caught again. Should I replace the plugs?

Oh yeah, what's a DVA?

Grant in Vancouver

 

[Laddies]

Re: Switchbox killing Stator?

If the engine has not had plugs lately it probably wouldn't hurt but in most cases it's a waste of money, you might ck the engine for spark on all 3 cyls, with a spark gap it should jump 7/16 " pretty easily. A DVA is a meter or a adapter that captures peak voltage from a ign. system and is nessicary because it's a an AC system. It's easy to use first you ck. voltage from the high and low speed windings of the stator, next you ck each trigger wires for voltage, if both the stator and trigger pass the voltage tests you test the each coil lead at the switchbox, if they are putting out the required voltage and you are still losing spark on 1 or more cyls you have a bad coil or wire, if the output at the switchbox is low or none, from 1 or more lugs you have a bad box or shorted coil. It's a piece of cake with the proper tools. It does sound like you may be losing a cyl.

 

[Cape Coder]

Re: Switchbox killing Stator?

I have a 1985 60HP 3 cycl my engine wouldn't go past 4,000 RPMs WOT if I just got on it. If I ran it for around 20 mins then opened it up it ran fine 5800 RPMs for the rest of the day. Someone told me to replace the switchbox and that solved the problem. I didn't have the blue smoke that you're having though. I bought the switchbox on boatfix.com & put it in myself. It's easy to do.