Dear friends,
I have been struggling with various engine problems the past time.
Basically everything under the hood has been gone through, in detail.
Several issues have been worked with and components have been renovated/replaced.
The engine now starts perfectly and runs smoothly, on IDLE (!).
Responding quite fine as well as the accelerator/throttle kicks more fuel in.
However, when put into gear and load increase, the behavior is very strange.
It's extremely weak, coughs and when load increase more it dies.
Starting things up again, engine starts directly but the problem repeats as soon as the smallest load is added..
I have checked:
- Ignition timing (calibrated based on UDC and checked by strobe-light on cyl #1).
- Breaker contact (measured. But as things runs smoothly on idle it cannot be an issue)
- Coil (as it works on idle it cant be poor. Resistance measures are also OK)
- Compression (which shows more or less exact the same numbers for all cylinders)
- Mixture screw, on carburetor (2 to 2.5 laps unscrewed versus the "dead mode")
- New spark splugs
- Wires checked and absolutely no issues.
In regards to the spark plugs, there is obviously a problem as they (all four) turn very black/grimed)
I'm using a new set of NGK B6HS., as recommended by another 170 owner.
So, the question remains - How can the calibration for idle-run be so perfect, but at the same time so bad when load is added?
Obviously I am missing something out here... ?!
Thanks in advance!!
/Thomas