Hi all, having some trouble with my 1999 Cobalt 206 Volvo Penta 5.0Gi (PWTR) with a DP-SM outdrive.
About a month ago on after 14 mile run with the boat running at 2800-3100rpm, as I came back off plane I noticed a very pronounced vibration that has not existed before. The vibration now continues, when under load, at certain RPM's. 1400-2000rpm, 2900-3100rpm and then again at 4200ish-4400rpm.
The vibration itself has a wobble feel to it, especially at the lower range. It only occurs in gear, under load.
The props were fine, I had them refinished and balanced just to be sure. The prop-shafts are fine.
I replaced the U-joints (Sierras) and Gimbal Bearing (OEM Volvo), 2 years ago when I felt a very slight abnormal vibration when turning or not trimmed out. This resolved the vibration that time (Which was less than what I am experiencing now)
Alignment is checked yearly. It seems to be fine. I can insert and remove the tool with 3 fingers.
The boat itself runs well, idles fine, can get up to WOT without issue. The high pressure fuel pump is whining, and is going to be replaced along with the Low pressure.
About a month ago on after 14 mile run with the boat running at 2800-3100rpm, as I came back off plane I noticed a very pronounced vibration that has not existed before. The vibration now continues, when under load, at certain RPM's. 1400-2000rpm, 2900-3100rpm and then again at 4200ish-4400rpm.
The vibration itself has a wobble feel to it, especially at the lower range. It only occurs in gear, under load.
The props were fine, I had them refinished and balanced just to be sure. The prop-shafts are fine.
I replaced the U-joints (Sierras) and Gimbal Bearing (OEM Volvo), 2 years ago when I felt a very slight abnormal vibration when turning or not trimmed out. This resolved the vibration that time (Which was less than what I am experiencing now)
Alignment is checked yearly. It seems to be fine. I can insert and remove the tool with 3 fingers.
The boat itself runs well, idles fine, can get up to WOT without issue. The high pressure fuel pump is whining, and is going to be replaced along with the Low pressure.