MacGregorSailors.com

I have a 1985 M25 that I'm trying to restore. I was wondering if the pop top ever had a gasket because I see some glue where a gasket would be? If it does have a gasket, then what kind gasket and where do I get one?

Blue Water Yachts

https://shop.bwyachts.com/product-p/4001-1v0.htm

I ordered the gasket and have already installed it on the foredeck hatch and cockpit hatch. Both hatches are a little hard to close with the new gasket installed. Gasket is too thick, hopefully I get some gasket setting so that the hatch's close better.

Before installing the gasket on the pop top, I noticed I was going to have a gap on the starboard and port side of the pop top near the bow end. I installed the gasket today, now I have a gap, see pics. I'm wondering if my pop top itself is from a different Macgregor model boat, or maybe I have the right pop top but the Design/Manufactuing is a little off allowing the gap. Also, with the gasket installed the pop top is resting on the deck. Please help. I'm trying to keep any mosquito's out.

With the clearance to small in some areas and too great in others, it definitely appears as though the pop-top and the opening don't match, whatever the reason.

Moisture is going to be a bigger problem than mosquitos, it looks like, so you will need to build up the edges so that they seal. The challenge will be tapering them so that they seal reasonably well at the ends. I would suggest using plastic trim strips from Home Depot. They are about an inch wide and 1/8 inch thick. You will find them in the trim section. Hopefully you have a belt sander for easing the ends. Attach with Liquid Nails, screws, or bolts. If you use screws or bolts, get the flat-head type and countersink them so they don't cause gaps at the seal.

You seem to be missing the hold down brackets (would go on the long stud in your first picture). If you install those, you should be able to tighten them to pull the sides down.

https://shop.bwyachts.com/product-p/4805-1c2.htm

Alternatively, you could double up the gasket by just sticking a second layer to the top of the first. Or you could look for a taller gasket on McMaster-Carr.

My M25 pop top is also not a prefect fit. I think it's just hard to make two large, slightly curved surfaces match up perfectly, and Macgregor had a strong sense of "good enough."