Mounting Bolt Overtightened.

[Eye Fish]

Looking for some input from members who may have experienced a similar issue or are knowledgeable regarding this problem.

Because of supply chain issues, the dealership where we purchased our new Key West FS263 with twin 200s mounted the engines as opposed to the manufacturer doing so at the factory. The boat was delivered in November 2022 and used roughly three days a week since that time. – a little over 50 hours on the engines.

Recently while adding some electronics, the independent technician working in the bilge noted that the lower port engine bracket bolt had apprently been overtightened cracking, at least, the cosmetic fiberglass inside the transom and exposing the core (picture). Which resulted in a small leak when the boat is in the water (the boat is lift stored).

The logical assumption is the bolt was overtightened. However, it also seems logical that bigger washers would have provided more back plating by spreading the stress over a larger area of the transom. Or better yet, a lower bolt transom plate would have provided the same load distribution on the transom as the plates with the Key West logo on the two transom bolts above the water line.

Given the boat just went to the dealership to have the fiberglass repaired and the situation rectified, and they have not started on it yet, should we be asking for larger washers for all four lower bolts or for a lower back plate the same as the top tow bolts be added? Also, any thoughts on what sealant is recommended for the bolts below the waterline would be appreciated.

We love the boat and even more so love Yamaha outboards. This is our fourth boat since stepping down from inboard diesel powered larger models 13 years ago and we would not even consider using any other outboard engines. Our issues here are with the dealership and the job their service department did mounting the engines – not Yamaha. We just want to make sure the engines where mounted properly to begin with and, certainly, that the fix they are proposing is correct and permanent.

Thanks in advance for any thoughts

[panasonic]

That's a tough problem you have there. It may have been overtighten for sure BUT it is in a bad spot right next to that radius in fiberglass. The washer on there now is to close to that curve.

Can the engine be shifted over an inch to keep that bolt away from the radius in the transom? You could use a larger washer then. What about the other mounting bolts...are they in similar spots?

[panasonic]

The proper way to mount the engine to keep from crushing the transom is mount the engine and mark the holes. Remove the engine, drill the holes oversized, pot in stainless steel sleeves that are the same thickness of the transom and the mounting bolts will fit through snugly. Reinstall the engine and put mount bolts through the sleeves with 3M 4200 or equivalent sealant and tighten. The sleeves will keep the bolts from crushing the transom. Do you know what the core of this transom is made of?

[99yam40]

fix should be from the manufacturer; I would not trust it from someone else

[Eye Fish]

Thank you for your input.

The starboard bolts are both fine and with the outside one not being anywhere near the fiberglass curve, bend to be problem.

I believe the bracket holes came pre-drilled from the manufacturer. There are in the picture I took of the boat when it first arrived at the dealership from the manufacturere a month and half before the engines arrived. So I’m assuming these can’t be relocated.

The core is a composite of some sort – not wood. Which in this situation is good as I understand there is very little chance of water penetrating the core material as it would wood.

[TownsendsFJR1300]

On my single, F150, the large washers.'

I've seen "Plates", basically about 2" wide that goes all the way across the transom (where you see my washers) .
That gives even more distribution, which bolts to both upper bolts as one piece...



Yamaha #6.JPG

[DennisG01]

Comparing your first pictures and the one of the transom... it "appears" the engines aren't exactly centered vs the centerline of the boat. Now, I'm only looking at pics and one of them is from an angle, so measure in person. But this is 100% between your Key West dealer and KW, the company. Yes, the larger the washers, the better - but you can only go so big on certain bolts given the proximity to the "curve".

[Eye Fish]

I just spent about an hour at the dealership with owner.



Long story short it looks like KW had their jig misaligned when they drilled the transom holes at the factory. Everything is off site about a half inch to port – which explains why the washer crushed the transom radius on that side in the bilge.



So the dealership is looking to repair the transom and leave the engines where they are.



They said that being off half an inch should not impact structural integrity of the transom, engine performance or engine life. I’m not sure I’m buying that but wanted input from all of you on the Yamaha forum as to whether that sounds or is plausable.



A big part of me wants the boat in the water ASAP and not having to send it back to KW in South Carolina to have new holes drilled a half inch away from the current ones is appealing. But not at the expense of creating bigger problems down the line.



I attached a couple of pictures (Please don’t even ask why the dealership would have poked the transducer wire hole below the waterline for a transom mounted transducer. That is another fish to fry once I’m past the engine mount piece under warranty)



Thanks in advance for any input

[DennisG01]

In reality, no, I don't think 1/2" is going to matter in the real world. But here's the thing... if you accept it, then it becomes YOUR problem to possibly try and explain to someone you sell it to down the road. Granted, most won't even pick up on it, but if they do it could compromise your sale or lower the resale value. There's no reason the holes can't be properly repaired and re-drilled.

[Eye Fish]

Thank You all - this has been very helpful.