130 HP unstable idle

[Donald Breslow]

1990 130 HP. Unable to obtain stable idle with cowl installed.

When idle is set with cowl off to 900 RPM in neutral, it is very stable. When the cowl is installed, the idle slowly drops to 400/500 rpm, and then stalls. Takes about 1 minute to drop to stall. While dropping, opening the cowl about 1 inch or more, idle recovers. Using control lever with cowl on, a fairly big throttle setting can establish a stable 900 RPM idle. When cowl is partially lifted, engine speed can rise to 1500 - 2000 RPM.

Ran compression check. 4 cylinders were 140, 145, 145, and 150.

Suggestions please .

Don Breslow

[TownsendsFJR1300]

Someone posted a similar issue not too long ago but I'm un-able to find the thread (and don't remember the fix).

Someone will chime in witrh the fix, it wasn't anything major as I re-call...

[99yam40]

Sounds like exhaust leaking into cowling causing starvation of O2
or intake hole is plugged with something maybe

Compression #s are higher than I have seen on most 2 strokes, but could be the gauge

[TownsendsFJR1300]

Sounds like exhaust leaking into cowling causing starvation of O2
or intake hole is plugged with something maybe

Compression #s are higher than I have seen on most 2 strokes, but could be the gauge

Yepper, that was the posted fix, exhaust was seeping in choking out the engine.