Flywheel / Coupling Information

[Chris Baranyar]

I have a 2003 Searay 182 Bowrider that was bought new.I have replaced my 2003 inline 3.0 liter displacement Mercruiser engine w/ a new long block engine. I put all the original ancillary components on the new motor. I ran the motor just fine for about 30 hrs. of run in time. Everything was fine. I opened the throttle 2200 RPM max. Everything was good for about 10 minutes, boat got on plane then speed dropped, as vibration started. I was able to run at about 5 to 10 knots with no vibration and made headway back to dock. When I got the boat out of the water I shifted into both forward and reverse (engine not running) . I was able to rotate the propeller in one direction in forward and rotate it in the opposite rotation when shifted in reverse. Is it possible the internals of the coupler bolted to the flywheel has failed. Is there anybody I can get information on the inner components of the coupler? Note I did start the motor after evaluation in neutral. Everything from starting and idling are perfect.

 

[Scott06]

My family had a very similar Sea Ray 170 with a 3.0 for many years ...20.

The coupler is just a rubber hub with female splines that the drive shaft fits into. If engine alignment wasn't check after new engine out in its possible that the coupler let go, especially if rear engine mounts weren't assembled with the washers that go in there .

First check the hub on the prop isn't messed up. Assuming you have a solid delrin hub just take prop off and look at it, will be obvious.

Is it maintaining temp ok when in the water and running? If driveshaft isn't turning on an alpha the water pump impeller won't turn and engine will over heat.

Best way way to check is take 15 min and remove the drive look at drive shaft splines for damage. Look through gimbal bearing into coupler for spline damage or rubber pieces typical of when rubber lets go. Also check drive has no upper gear damage by shifting into gear and turning input shaft feel for roughness and if proper shaft turns. Pop top cap and check drive oil for metal shavings if drive doesn't feel right.

What happened to priginal engine that required replacement

 

[harringtondav]

Problems normally have there root in "what changed". You changed your engine, Scott06 's advice about checking alignment is solid. Get yourself a Merc alignment tool. Reasonable on eBay etc. Any boat owner should own one for regular out drive pulls and inspections.

A misalignment that pulls down engine revs without a lot of noise and commotion may happen, maybe. The alignment bar will check this. Also recheck "all the original ancillary components", especially the fuel system. A fuel starved engine will stutter, fuss and vibrate.

That's my brain dump. Good luck.