What component controls SLOW mode ?

[Sean Lloyd]

1989 gt 150, model # J150STLCEM- My motor went into slow mode and wont reset...no longer alarming, however wont go over 2200 RPM's. Spark in all 6. decent compression(same compression as this spring, all within +/- 10.) What needs to be changed? stator? powerpack? what actually controls SLOW? thermistors in the cyl. sets it off, but what would keep it off?

 

[seahorse5]

Re: What component controls SLOW mode ?

When the tan wire on either cylinderhead temp switch activates and completes a circuit to ground, the powerpack senses the change and limits the engine rpm in the Speed Limiting Overheat Warning, SLOW, mode.

If the tan wire is grounded elsewhere, such as a wire rubbed against the motor block, the motor will also activate SLOW.

Inside the engine wiring harness, there is a diode which isolates the temperature tan wires from the other warning tan wires. If that diode gets shorted internally, any other engine warning - Low oil, No Oil, or Fuel Restriction - will put the motor into SLOW

On rare occasions, a faulty powerpack will stay in SLOW.

 

[jonesg]

Re: What component controls SLOW mode ?

Is the alarm system working?
It might not be SLOW.

Is there an assist shift switch on that yr motor?
Does it have dual power packs?

 

[ezeke]

Re: What component controls SLOW mode ?

The powerpack controls S.L.O.W. The toubleshooting steps shown here may be helpful: http://cdielectronics.com/InstallSheet/113-3865.pdf

See: "ENGINE WILL NOT ACCELERATE BEYOND 2500 RPM (Runs smooth below that RPM)"

 

[Sean Lloyd]

Re: What component controls SLOW mode ?

Thanks guys for your assistance. The warning system is still working. It tested good and still sounds for 1/2 second when key is turned. This motor has only one power pack and it was changed in June because of poor and random spark. I replaced the power pack with a CDI unit and the boat ran like new. Now this...is it possible the power pack is already damaged? Or could it be a manufacturing defect? Is it common for a motor to not come out of SLOW? Did I blow the power pack? Is there some other way to manually reset the SLOW switch through the power pack by sending it some other signal? Sorry in advance for my ignorance, but this is my first experiance with a SLOW mode that wont shut off. Thursday I will retest the power pack per manual instructions. I'll repost tomorrow with all my test results for everything. I just don't want to start replacing parts without an understanding of what caused what. Again thank you for your responses.

 

[Sean Lloyd]

Re: What component controls SLOW mode ?

Sorry jonesg- assist shift? I'm not fimilliar with this. Where would I find that info? Thanks

 

[jonesg]

Re: What component controls SLOW mode ?

How do you know its in SLOW mode?

Check the shift arm inside the lower engine hood, look for a switch that is actuated by the shifter, if it has the switch, unplug it and test for spark again.

I would also clean the plugs on the powerpack from the stator, spray with CRC elec cleaner, look for corrosion.

 

[ezeke]

Re: What component controls SLOW mode ?

Once S.L.O.W. is activated the engine must be turned off AND reach a temperature below 162? F. in order to to disable it.

Since S.L.O.W. is normally only activated by overheating, it would be best to find the source of the problem; either a temperature switch or a short to ground.

It is possible that the blocking diode in your harness has failed, allowing other warning signals to reach your powerpack.