1993 C115TLRR - Won't run over 2k

[FJ Texas]

Good Afternoon, new to this forum; have a 1993 115 2-stroke. Was working fine now seems to be stuck in safe mode. Motor is hard starting and will not go over 2000 rpm. it seems to "choke itself out if I push the throttle to anything past 2000rpm. Have cleaned and rebuilt carbs and replaced fuel filters and gas. Any thoughts from the legacy folks on the forum. Leaning towards a stator issue from what I am reading, but have not dived into that yet.

I think I have ruled out fuel or overheat problem, as I tried backing trailer down the ramp, after hard starting, let warm up for a few minutes tried accelerating while still on trailer and it would "choke" itself out over that 2k mark.

The hard starting and reading about the under 2k and over 2k sections of the stator are what are heading me in this direction. Ideas for testing? Thank you.

[TownsendsFJR1300]

Any alarms (especially over heat) showing?

[DennisG01]

Does the fuel bulb stay hard/full? Or does it flatten out?

[FJ Texas]

Thank you for the responses, no alarms and fuel bulb is hard. Thought maybe it was junk in the carbs so I rebuilt those. Starting is now difficult but runs smoothly at idle once it’s running.

note, I just purchased the boat in May and have been bringing it back to life. I don’t know how long it sat prior to my purchase.

[99yam40]

CDI electronics has a web site that you can look at on line with troubleshooting/testing info.

My Brother in law called me a few weeks ago about his 2 stroke 50hp running like you mentioned.
I checked compression and spark on all 3 cylinders and found that OK so we took it to a ramp and backed it i the water and fired it up, he does not have a tack, but when trying to raise RPM even after a warm up the motor would die when you opened up the throttle slowly or fast.
took it back to his house and I went thru the carbs.
the bottom one had some loose stuff on the bowl and I saw the main jet partially plugged.
we cleaned all the jets .
put it back together and it runs fine now.

I do not under stand the motor dying from one carb having a problem, but I did not find anything else wrong with it

a inductive timing light hooked to each plug wire one by one should show if they are loosing spark also you can use a spark tester.

some motors have low and high speed charging coils, so you need to find a manual for you motor and follow the testing procedures in it

You need to test the alarm system to make sure it does alarm when it should

[FJ Texas]

Thank you,will look at that website. I purchased a general Yamaha repair manaul that has a range of motors in it. It could use more detail. But provides great info on concepts and then leaves you to find a source for details. The carbs were my first choice. Really thought that would fix it. Will update later.

[FJ Texas]

Update....I was able to do additional trouble shooting over the weekend. I pulled the Stator test sheet from CDI website (Thank you). Ohm measurements were within the ranges required. So it looks like the Stator is not my main problem.

I picked up a simple ignition test light you connect between the plug wire and the plug. Tested each plug/wire combination. According to the test, no spark (no flashing light during cranking). I know the plugs are good as they are new (replaced in June). My question now is; Is it reasonable to think that the 4 ignition coil assemblies are bad at the same time? Or is it more likely a Coil Pulsar (Did not see a Coil Pulsar test sheet on the CDI website)? If it is likely the 4 ignition coils went bad at the same time I will go that route, but I don't just want to the throw parts at the problem, at the same time, I don't want to dig into the flywheel removal and possibility of damaging something else if that is not necessary. Or does past experience state that when the Coil Pulsar goes bad it surges the ignition coils and it all needs to be replaced?

Thanks again for all the advice and input.

[99yam40]

I would not think the 4 ignition coils are all bad.

I would take peak voltage reading of the inputs to the CDI and the outputs.
that is a lot better than ohm reading
Get a DVA adapter or make one if you do not have the proper meter to get these peak voltage reading.

that web site should have given peak voltage specs for charge coils , and pulser coils
the charge coils furnish the voltage to charge up the caps in CDI
some motors have a low speed and a high speed charge coil

the pulser coil tell the CDI when to send spark to the ignition coils
you need to know what is in spec and what is not.
the peak voltage readings are minimum reading the voltage can be higher