1991 25HP Merc "kills" at half throttle

inthwtr

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Cant figure this one out. Engine runs fine at low speed but as soon at I (its a tiller) twist it to more than half throttle, it dies. Almost as if the ignotion is "killing" it.
Again, the engine runs fine at just below half throttle.Suggestions please!:%
 

tashasdaddy

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Re: 1991 25HP Merc

Re: 1991 25HP Merc

could you be hitting the kill button by accident, does it have a lanyard that could have a loose fit. have you check the wiring,
 

Laddies

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Re: 1991 25HP Merc

Re: 1991 25HP Merc

Unplug the kill wire at the switchbox (blk/Yellow) be sure it is the one to the kill switch as there are 2, mercurys messup I guess if it don't run then it's probably thr high speed winding on the stator. It can be OHM tested
 

tashasdaddy

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Re: 1991 25HP Merc

Re: 1991 25HP Merc

go t outboardparts.com mercury trouble shooting, there is a step by step procedure. i point you there because our engine faq section is and has been down.
 

inthwtr

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Re: 1991 25HP Merc

Re: 1991 25HP Merc

Laddies said:
Unplug the kill wire at the switchbox (blk/Yellow) be sure it is the one to the kill switch as there are 2, mercurys messup I guess if it don't run then it's probably thr high speed winding on the stator. It can be OHM tested
I have checked the wireing and even tried disconnecting the kill switch. It still does it. Can you explain what a high speed stator does?
 

inthwtr

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Re: 1991 25HP Merc

Re: 1991 25HP Merc

tashasdaddy said:
go t outboardparts.com mercury trouble shooting, there is a step by step procedure. i point you there because our engine faq section is and has been down.

Outboardparts.com seems to be down. I cant get any of the pges tp open
 

Laddies

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Re: 1991 25HP Merc

Re: 1991 25HP Merc

Under the flywheel there are 2 winding that produce the AC electricity to operate the ign system one is for starting and low speed operation as the RPM increases the low speed would produce to many volts for the system so it has a high speed winding that takes over and it also acts as a resistor (for lack of a better term) for the lowspeed for power at about 2500 RPM
 

inthwtr

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Re: 1991 25HP Merc

Re: 1991 25HP Merc

Laddies said:
Under the flywheel there are 2 winding that produce the AC electricity to operate the ign system one is for starting and low speed operation as the RPM increases the low speed would produce to many volts for the system so it has a high speed winding that takes over and it also acts as a resistor (for lack of a better term) for the lowspeed for power at about 2500 RPM
Now this is starting to make sense!!! Where do I get this winding to replace!?!?!? And Thank you!
 

tashasdaddy

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Re: 1991 25HP Merc

Re: 1991 25HP Merc

maxrules.com, mercpartsexpress.com or a dealer.
 
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