1998 Yamaha c150 not sitting level

[devin622]

Hey everyone,

Last year while dropping my 21 foot Sea Pro with a 1998 Yamaha C150 outboard into the water for the season, the lower shaft from the outboard mount came out due to a "bumpy" road and my transom bolts not being tight enough. At the ramp I was able to lift the bracket get the shaft back in and attach a c clamp to it. I tightened all outboard bolts and i was on my way. This year while riding behind the boat to put it in the water again i noticed that the aluminum anode looked lopsided, and after further inspection it looks like the whole transom mount was lopsided. This outboard uses a slot style bottom fitting where the lower bolts go thru the transom, and its about 1/2 inch lower on the side that came undone last year. The outboard itself is not level due to this and its really bothering me. Is this something i can fix while the boat is inside the water? Also im not really understanding how this part could have dropped 1/2 an inch when the upper bolts are a fixed position.
Excuse my lack of knowledge in these parts. Motor bracket for reference below.

Thanks,
-Devin

[devin622]

IMG_2287.jpg

[ausnoelm]

Not happy with the other advice?

[DennisG01]

It's a little tough to follow everything you are saying... are you from another country? There might a small language barrier. BUT, I think I understand that you are saying the motor bracket is not "staying put"? Meaning, looking at the engine from behind, the engine is rotating either clockwise or counterclockwise? It also sounds like you tightened some bolts up but did nothing to reseal them? There'd a good chance you let water into the transom since the seal would have been broken.

Now, going only off the information you mentioned, it sounds like the upper mounting holes have gotten elongated. Which brings me back to wondering if the transom core is damaged. It would be a good idea to check your transom to see if it's gone bad. Loosening transom bolts - and especially not resealing them - is usually a pretty good indicator that the transom core is failing.

[99yam40]

I too think the transom is giving way and allowing the motor to move

[devin622]

Theres no wood in the boat, all foam cored, rock solid, I had it checked when i purchased the boat. I never checked the the bolts when i bought the boat 2 years ago. My guess would be the previous owner didnt check them regularly either. Bolts should be checked and torqued to manual specs seasonally, i know this now. I dont believe the bolts loosened at all since the first mishap while transporting. I was planning on taking the boat out, loosening the bolts, leveling the engine and re securing them. How can i go about resealing it while im doing this, does the whole engine need to be removed to reseal it?

[DennisG01]

Some boats have fiberglass floors, but still a wood transom core. Are you sure you don't have a wood transom? Either way, something has elongated and it's unlikely to be the holes in the bracket - and even with a composite core, the holes could still have elongated from being loose. It's just something you'll need to lift the engine off (got a big tree or a garage?) to check. Simply sealing them back up and tightening is not the proper way to do it. Removing (4) bolts, a $30 come-a-long and an hour or two is all you need.