I'm going to be going from 4.0" exhaust to 4.5" exhaust tips.
Thinking about using poly to seal in the transom cutouts.
Any suggestions?

Thanks,
Dennis

I would get the 3M marine sealer/adhesive for below the waterline if it were me.

Actually I was talking sealing the width or thickness of the wooden transom.
You're right though about sealing in the tips.

Dennis

I would use West Systems Epoxy resin if it were mine!!

I did the same exact thing last year. After cutting out the holes and making sure that everything fits, seal the wood with whatever epoxy you have. It doesn't have to be anything fancy, just a sealant. I used some 5 minute epoxy that was laying around with no problem. DO NOT use 5200 or anything even semi permanent on the tips, you'll pay for that later. I used marine "goop" on the tips themselves to the hull on a recomendation from a trusted source. Don't be afraid of making the holes too big either. I drove myself crazy getting the exact size hole saw only to end up using a drum sander to make things fit.

Rene

Could only find a 4.5" holesaw so I ended up drum sanding to enlarge and finish out the hole.
One done and four mo to go..........

You can put the small hole saw in the middle of the big hole saw and it will line the holes up perfect. Freind of mine hooked me up with that.

Yup that's what I did.
Got the two center holes done on the Fountain.
What a pain in the ass.
Bad part about it is I had to put everything together to make sure I had room for both exhaust
hoses on the center pipes then remove everthing to seal the transom with resin.
This is on a staggard setup
Tight very tight.........
One more hole!

Dennis