496 mag engine coupler
 

I have a 25 outlaw with a merc 496mag. Last season I noticed a strange vibration when under power. I can really feel it when I am coming out of the water, and it gets a little smoother once on plane. It is not too sever, but enough to tell me that something is not right. I have replaced and/or swapped out everything in the driveline- I tried a completely different drive (with a different prop), and still the vibration remains. I have come to the conclusion that it must be the coupler itself is tweaked or off-center. The problem that I am having is that the coupler that I need seems to be out of stock everywhere that I look. Does anyone know where I can get a new one at a reasonable price? Any suggestions would be helpful. I am trying to get a head start on it before it gets warm in Wisconsin.

Thanks!

Post your engine serial number and I will see tomorrow if I can find one brand new.

Serial number is OM364791

when does it get warm in cheese land?someone told me your boating season starts in august and ends in september.

I just thought about this as someone else I need to post to with an alignment issue. Anyways OEM problem that has pointed to your and his problems. Here it is.

you will need 2 tools for this

a correct spec alignment tool - Gimbal housing alignment tool - Merc part number is 91-805475A-1

next tool is OEM bell housing alignment tool Merc part number 91-863372

I can sell you these tools if needed.

The info is strongly recommended for checking very hard to achieve alignments and or vibrations. We have done this many times.

The first test is to stick the alignment tool all the way in (drive off of course) water supply to the engine and start the engine with the alignment still in and now spinning around. Watch to see how well the alignment tool spins a perfect circle - if not you have a coupler problem of some sort or 4 surely a warped coupler. If not and the coupler is all good the next step to check for pin pointing the problem of the vibration and or miss alignment

If there is a vibration problem when running the engine (drive on ) - remove drive for an engine alignment - this should be checked out very thoroughly and then added steps.

Install the engine alignment tool all the thru the gimbal bearing and into the engine coupler next is slide the bell housing to gimbal housing alignment tool over the end of the alignment tool - the smaller steps towards bell housing (the tool) and up in the housing. ( the smaller steps should be inside of the bell housing case)

check the gap between the alignment tool larger step and the bell hosuing case at 90 degrees and at 270 degrees. THE GAPS should or need to be even.

If they are not the the front engine mounts should be checked for being properly attached ( even if to see if they are loose and or angled). If all correct - then they can be loosened up to see if the engine realigns itself side by side.

If there still is a difference in the 90 and 270 degree gaps after this - there may be a transom thickness issue that should checked out. Or you possible have a engine coupler issue. (warped) or so on.

You're not too far off... in the last few years we've been lucky if it was warm on July 4th! All the more reason to make sure that everything is running right - I don't want to be stuck out in the cold.

Thanks for the tips. I do have the gimbal alignment tool. I will try sticking it in and running it to check for warping of the coupler.

I would be concerned with engine alignment as it will cause vibration and ultimately fail your coupler. Over the years I've had issues with the leveling nut dropping on the engine mounts (tabbed washer not locked properly by OEM), easiest way to see if the motor has moved is to see if there is a gap between the top flange of the motor mount and the top jam nut. Alignment issues can also happen over time through movement in the structure (typically very subtle) or physical damage to the mechanicals.

I have offshore-style mounts, so there is no adjustment. I did check up and down alignment last year, and it was a little off. I ended up shimming the front of the block up a little to get perfect alignment. Still feel the vibration though. I will be checking the side to side alignment as soon as I can get it out of storage.

I finally had the chance to get the boat out of storage, and do some more tests on engine alignment. It appears that the coupler is definitely warped. I inserted the alignment tool, and turned the engine over. The tool wobbles in an orbital pattern as the motor turns- definitely not good. Looks like I will be pulling the motor in the near future. Now the problem is where to get a new coupler at a decent price, and do I need the heavy duty version? Does anyone know where I can order the part?