I have a SLX270 27 foot. When attempting...

[Makin_Memories]

I have a SLX270 27 foot. When attempting to drive higher than 5 to 10 mph the boat starts shaking and progressively gets worse if I attempt to go any faster. Any thoughts on what might be creating this?

[wingless]

The boat in this video also started shaking at the 2:37marker.

https://www.youtube.com/watch?v=upQ-MXF_ZgI

If yours is shaking as described during normal operation then my first guess would be the propeller. It may be damaged bad enough that a visual inspection would reveal the problem. The damage might require a shop measurement to identify / correct the problem.

[Makin_Memories]

Nothing visual wrong with the prop

[wingless]

Is a spare available to do a swap to see if that corrects the problem?

[kimo]

Twin o
r single engine ? need to isolate if from one or both engines Any vibrations coming from shaft/s

[Makin_Memories]

Single engine

[kimo]

Or props. Cld be either of all above. U cld have picked up loose lines - shaft brngs cld be worn with too much clearance - inbd shaft coupling/s cld have loosened a bit - Props may have backed off shaft taper a bit - engine mountings all tight/secure etc can be all possibilities but first thing is to determine if vibes are coming from engines/transmission or from other sources then you can work backwards from there. If nothing obvious from inside boat then get over the side and just see if prop/s cld be fouled. If again nothing obvious then last resort is u need to haul the boat and check shaft/strut brngs/props etc. Good luck. John.

[Makin_Memories]

Turned out to be from the spark plugs. Once all replaced it ran fine