Ksoulant
Member
I have owned a Jefferson 46 with twin 260hp 3208T for the past few years and have always felt some vibration and of course most of the vibration is at the best cruising RPM (1500-1800). I measured both shafts and couplings with a dial gauge the port drive train was out 5 thousandths and the Starboard was out 20 thousandths. From what I have read this reading should not be more than about 8 thousandths. So at this last haul out for bottom paint I had the yard do the following on the starboard drive train.
Removed prop for balancing.
(It had no dings and was in very good shape with very little balancing needed).
Removed shaft for straightening.
(The prop end was 7 one thousandths out and the coupling end was 15 one thousandths out. It was straightened to 3 and 5).
Removed and refit shaft coupling.
(The coupling was found to be wobbled out and would not face up to the shaft. It was also found that the keyway slot on the shaft was not straight. So they cut a new keyway slot 180 degrees on the shaft, replaced and refaced a new coupling).
Replaced motor mounts.
(2 motor mounts were bad but all 4 were replaced).
Replaced cutlass bearings.
(Cutlass bearings were worn but not bad).
Removed struts and realigned.
(The struts were out of alignment by 1/8th inch they were lowered and realigned).
The boat was launched and 48 hours later the engine was realigned on its new mounts and connected to the new coupling.
After running the boat for the first time the vibration is still there and the shaft and coupling is still out 20 thousandths of a inch. Does anyone know what the problem may be or if there is anything else I can do? Or did I just through 4 grand out the window?
Removed prop for balancing.
(It had no dings and was in very good shape with very little balancing needed).
Removed shaft for straightening.
(The prop end was 7 one thousandths out and the coupling end was 15 one thousandths out. It was straightened to 3 and 5).
Removed and refit shaft coupling.
(The coupling was found to be wobbled out and would not face up to the shaft. It was also found that the keyway slot on the shaft was not straight. So they cut a new keyway slot 180 degrees on the shaft, replaced and refaced a new coupling).
Replaced motor mounts.
(2 motor mounts were bad but all 4 were replaced).
Replaced cutlass bearings.
(Cutlass bearings were worn but not bad).
Removed struts and realigned.
(The struts were out of alignment by 1/8th inch they were lowered and realigned).
The boat was launched and 48 hours later the engine was realigned on its new mounts and connected to the new coupling.
After running the boat for the first time the vibration is still there and the shaft and coupling is still out 20 thousandths of a inch. Does anyone know what the problem may be or if there is anything else I can do? Or did I just through 4 grand out the window?