Ive emailed you. the engine is quite a long way away, but a courier could deal with it. I would guess the height might be the same but you might have to shorten the shaft. Pure speculation though, im sure someone with more knowledge here on Gm engines will know.
I replaced a YSE 12 with a 2 GM 20 because the new engine could use the same height beds. I think you'll find Yanmar use a standard height between bed and prop-shaft for their smaller engines. There's a post in the technical section about living with a 2GM 20. It's worth a look. You'll probably need to change the exhaust manifold.
The advantage of Beta is that the engine family is widely used for construction equipment such as mini diggers. Spares are widely available both original equipment and third party. They are far less expensive than Yanmar.
I have attached some photos of our Beta 20 installation. I have (lots) more, which I can send you by email if you are interested. I think that the 14HP, 16HP and 20HP are very similar dimensions, so any would fit. It just depends how much money you have!
There are a number of gearbox options, which make a slight difference to the height and length of the engine. We have the TMC40 which is the smallest, and we put in 30 mm (I think ) spacers to make up the height difference. If doing it again I would make them 10 mm higher as the flexible mounts ended up very close to the top of their adjustment (I will put 10 mm packing under them at some point, but I had adjusted the alignment by that time, and could not face doing it again). The engine ended up just too high for our engine box, so we had to raise the top a bit.
One (no cost ) gearbox option that Beta have is one with a 8 or 10 deg down angle. That would make the installation much easier, with no need to raise the engine box.
I have included a photo of the rudder strap bolts. If you are removing the engine, I suggest that you take to opportunity to glass in the area around these bolts, as they are very prone to corrosion (crevice??), and can result in a leak if not changed regularly. Glassing them in solves this problem, but you only have access if the engine is out.
I hope that you find a good solution, and I am happy to give more details of the installation if you need it.
My only thought is that you are running out of time now. Our installation took a lot longer than expected, so we lost a good chunk of the sailing season last year. I think that you said that your current engine is running ok at the moment. Have you considered just keeping your old engine going for another season, so that would give you time to investigate different engine options in the next months, and then plan to have the installation done next Autumn / Winter when you will have more time.
Good luck, Nick
I'd note that I [we] purchased my Yanmar at the Earls Court Boat Show. The stand is manned both by 'Yanmar' people - the importer - E.P. Barrus and by Yanmar dealers. I was tipped off to ask for a 25% discount because they want to make sales at the show. I hate haggling but my co-owner is a hard man and very very good at it. He did the deal with the local [to me] Yanmar dealer at 25% off. It did take about 20 minutes. Useful to have a Beta leaflet in hand. I did, near the end, promise to buy all the spares from the same dealer.
Because the sale was at the show I much suspect that Barrus gave a special show price to the dealer. That's the way it generally works at such shows. So the dealer was able to give a better price...although he acted as if he was giving his last pint of blood.
I collected the engine from Barrus and saved £75.00. It fitted in my then company estate car.
£3,800 for an engine! For twice that I can buy a brand new engine attached to a sports car with 8" Colour Touch Screen, Apple CarPlay™ & Bluetooth® Integration.
Thanks for this Peter,
Sadly I don't want to wait for the show as I sold my old GM10 engine before all this business began.
On a brighter note it looks like I have found a recon GM10 from a local guy in Cornwall should be ready next week.
I have been speaking to Barrus who as you say are the main UK importer for Yanmar. Turns out Yanmar had a problem with their engine block supplier and pulled production on GM10 while they sorted it. Latest news is 10 weeks before any more GM10's at Barrus.
Thanks to all especially Nick whose Beta installation looks really neat, but as he says is not an overnight job and i am indeed running out of time.
My God, it's beautiful.