Hi!

I´ve got a R5 TS-90 with a monopoint injected C3J engine. My problem is this:

When cold it is starting and having a normal idle speed, but as soon it is getting a bit warm the idle speed is getting higher.
it´s almost at 2000rpm.
I´ve checked all hoses around the carburettor for leaks. No leaks.
Even tried to fix the idle speed motor. The motor doesn´t seem to work properly.

Does anyone know how to fix this??

/Jonas in Sweden

I have the same problem, but my revs are not going that high, it’s around 1100. I also took the Idle Speed Control apart and found that by applying 12 volts, I could cause the motor to drive the plunger out (reverse polarity, retracts). The spring-loaded contact in the ISC also makes contact when you push on the plunger.

When I reinstalled the ISG, it seems to retract all the way back, so that the plunger tip cannot move at all.

The Haynes manual says that when you turn off the engine, the plunger should come out (mine does not), then if you pull off the ISG electrical connector and restart the engine it should rev around 3500 +/- 200 rpm. Adjust the tip of the plunger to set high rev rpm. The nut should be heated with a soldering iron to loosen up the loctite thread locker before adjusting.

Then the engine should be turned off, ISG connector reconnected and the computer should set the idle rpm to some level which I have not been able to find in any book.

I tried this, but my ISG is fully retracted and there is no change in my high idle rpm.
My rpm is also lower before the engine warms up. Wander if the temperature sensor has something to do with it.