Just sharing my latest engine build ... RCMK 520 twin hybrid and now the Hull too .

Nice work Scott. Looks like it could be a winner.

Super COOOOOOOOL build Scott!!! You've got to post some vids of that bad boy in action!!!!!

Scott, great looking engine. Those carbs remind me of the twin side draft Dellorto's that I used to run on my 1600cc Avenger. I never used the chokes. Just pumped the throttle once, and the carbs would nearly flood the engine. They would squirt fuel 5-6 feet. In winter mornings a squirt of ether helped to get it going. I think that stuff is now banned here - too many druggies sniffing it.
David

I screwed up .... weight distribution with engine in the hull was not where it needed to be. Spent the last week redesigning and building some better suited sponsons.

So much for scratch building going smoothly .... live and learn

Scott.

That's the mark of a true boater: To recognize mistakes and correct them.
I really like the your design of the new sponsons, as they seem to carry and lift much better.
I had my eyes on this before, but I'm a polite old guy, and did'nt dare to play the "wise guy", as you really seem to have a lot of experience.
I wish you luck with your project. She looks much better and more convincing now!
Greetings from Denmark, and

Cheers!

Woodie.

I tell ya what Scott... That is one mean looking setup!!! Fantastic Job!!!! But keep one thing in mind... The beauty of scatch building is... you're the only one who knows if it's right or wrong!!! GREAT JOB!!!!!

Playing with pipes and headers .... this really is an eye opener on what a PITA twins can be when pipes fitted need to be short for max rpm and area or spread you have to work with is so limited :blush:

What ended up kinda fitting without doing custom head pipes was a 105* std on rear cylinder and a 2" offset 90* up front.

As I started figuring header length for pipes wishing to run just don't have much length to play with doing compound bends or profiles. This haphazard looking arraignment may very well just be what will be getting used early on

I can wait for someone to try a 2-in-1 and see what it does...can't be THAT bad...twin and triple 2-stroke snowmobiles use them all the time. I realize, not as good as individual pipes, but so much less trouble! lol

Anyway, how about getting someone like Carmen to make you a header for the front cylinder that goes up and back rather than out and back? Then use the 2" offset header on the rear cylinder and run that pipe as low as you can so you can keep the top pipe low too. Just a thought.

I thought about that arrangement in a bigger Cat to keep exhaust in boat but ran into same issues u did plus servo box
I was thinking u were using the BHH one's for the initial 'splash' like a BHH #10 and #11

Have a #11 and it's no help at all placing pipe along side tub.
A #10 would be the bomb helping out in the stacked pipe idea ... just frankly HATE aluminum head pipes

Have a bit of time yet.

As I had said, looking at my total head pipe length just can't get too creative in compound bends without eating up length taking pipes tuned length out too long :S