Stator and trigger testing

[GTMO Boater]

My 1996 Yamaha 225 Saltwater Series engine is intermittently firing on all cylinders. As soon as I accelerate it goes to about 4300 rpms and then bogs down to 1900 rpms an no faster. After fiddling around and checking a few things and starting and restarting I thought it was okay, until the next morning the same thing happened. I changed the spark plugs and saw where it wasn't firing on the # 3 coil. I changed the coil with another and all worked fine. Went to accelerate and after the same amount of time it went to 1900 rpm again. Someone mentioned my Stator or Trigger. Any comments or guidance?

Does anyone have the resistence parameters and what wires to check?

Thanks - GTMO Boater

 

[rodbolt]

Re: Stator and trigger testing

best is to test voltage output.
but first post a complete model number so we can ID which 225 you have.

 

[GTMO Boater]

Re: YAMAHA Stator and trigger testing

Re: YAMAHA Stator and trigger testing

Thanks for the quick response. Sorry I'm kind of a neophyte with this but I think it's an S225TURU. Yamaha 1996 V76x 225 Saltwater Series 30" shaft, Power Tilt and Trim. How do I check the voltage output? I'm in Guantanamo Bay and need to explain in Lehmans terms since there's not too many boat engine mechanics here. Thanks again.

 

[rodbolt]

Re: Stator and trigger testing

ok
you have a 3.1L carbed engine.
does the electic pump run when the key is on?
have you checked the three lift pumps for ruptured diaphrams.
the stator feeds voltage to the charge coil in port and stbd banks.
red to brown 115 v cranking loaded and 150v when running,same for black to the red/blue.
resistance should be 224 to 336 ohms.
pulser coil output,black is common to all 6, is 3v cranking and 16-30v running, resistance is 294-398 ohms.
all voltage tests require a peak reading type meter, RMS wont give proper numbers.
your kinda describing a fuel issue but use the AC part of the digital meter and you can make comparisons.

 

[GTMO Boater]

Re: Stator and trigger testing

Thanks for the info. I checked the trigger and all were in parameters while cold @ 367 ohms. After starting and warming up the engine, the #3 coil stopped firing again. I checked the trigger ohms again and the readings for all were off the chart. I guess the trigger is not working properly when the engine get hot. My friend with the same engine is going to take the trigger off his and see it it works on mine. Hopefully I won't blow his also. Is this a good idea?

When checking the stator it was a bit over 115V-want to say 120v. Is that OK.

Thanks - Mike in Guantanamo Bay

 

[99yam40]

Re: Stator and trigger testing

What are you calling trigger, Pulser coil?
and what does off the chart mean? open or some other high reading?
is that for all the readings?

What meter are you using to take the voltage measurements with?

 

[GTMO Boater]

Re: Stator and trigger testing

Yes, the Pulser Coil. All wires showed 367 on the multimeter while cold but after the engine warmed up the #3 coil stopped firing. We rechecked the readings on the pulser coil wires and all of them were spradic jumping from real high to low various readings.

We switched out the pulser coil from another engine thats identical and the engine ran fine. All I have to do now is find a pulser coil for sale.

Thanks to everyone for your posts.

Mike in Guantanamo Bay

 

[99yam40]

Re: Stator and trigger testing

Are you sure it was not a bad ground or other connection?
Just something to look at.

 

[rodbolt]

Re: Stator and trigger testing

like 99yamaha says, the pulsers on that engine share a common ground wire. inspect it carefully.

 

[GTMO Boater]

Re: Stator and trigger testing

I replaced the stator and everything seemed to run fine. Now the #5 cylinder won't burn at all. I changed the spark plug and it sparks fine, it's not flooding and fuel is correctly flowing, fuel pump is fine, the coils are fine, everything seems to check fine EXCEPT it won't fire.

Where do I go next? Appreciate the assistance in advance.

Mike

 

[99yam40]

Re: Stator and trigger testing

you need good compression , strong spark at the correct time, and correct air/fuel mixture to fire. check until you find what is missing

 

[GTMO Boater]

Re: Stator and trigger testing

Finally got it going. I went back to the basics and started from the start with the fuel since spark was there. The carb was not getting enough gas and had a little blocakge. I removed it, blew it out with some carb spary and now runs like a champ.

THANKS Everyone for your assitance.

Happy in Guantanamo Bay

 

[GTMO Boater]

Re: Stator and trigger testing

Finally got it going. I went back to the basics and started from the start with the fuel since spark was there. The carb was not getting enough gas and had a little blocakge. I removed it, blew it out with some carb spray and now runs like a champ.

THANKS Everyone for your assitance.

Happy in Guantanamo Bay