My thundercat

[Roflhat]

Put the 70 carbs back on to try get some better acceleration

The 50hp stacks fit on these too. Also painted the cowl, getting some custom stickers made




Also got another prop, 11x18p Merc Cleaver but the newer kind. Absolutely mind condish

[Roflhat]

Ran terribly with the stock carbs yesterday, going to order 3x carb rebuild kits and take it from there. Took about 40 pulls to start and would die every time I put it into gear. Getting around 120psi with the TSR head, less than I was expecting but hard to judge anything by static compression.

[Roflhat]

Got the stickers on, looks alright IMO


Also got a new prop, 16p Radice in brass, set a world speed record in 1979 on a Yam 55


Engine is running properly, the gasket on the carb bowl on the bottom carb wasn't seating properly and one of the spark plug tips had come undone. Still dropping onto 2 cylinders occasionally so need to have another look but it's running really well, finally! Dropped it down to 10mm off the transom and tried some of the smaller props to check acceleration.

Got 46 knots with the 14p vengance, acceleration is very good.
49.3 knots with the 10 3/8 x 19p overhub cleaver, acceleration isn't great because the exhaust isn't drilled. Great top end pull though
SOLAS 15p cupped ran ok but not as good as it did on the tohatsu, 46.5 knots with decent acceleration
The 16p Brass needs a different washer at the nut end, the hub is slightly different.
Best of the bunch was definitely the 15G Yamaha, 47.6 knots with incredible acceleration and unreal grip through the turns. Think I'll get this one worked

[Roflhat]

Bit of an update, engine started dropping onto 2 cylinders, then onto 1. Took the plugs out and it was fouling badly (oil). So I'm now running 50:1 with a set of new plugs and it's running much happier now, plugs are perfect.
Engine is now completely standard, even got a standard airbox for it. Runs awesome, feels very smooth thanks to the balanced crank, much more so than the tohatsu at low RPM.

More props and more testing, got a 2 blade brass prop, 10 3/8 x 17p. Unfortunately first time out it spun the hub... so it will be getting sent off to get a new hub.


Best prop is still the 15G yamaha, now getting a consistent 50 knots with it. Really nice prop, although I'd still like a 16G for a bit more top end, the 70hp has no problem spinning up the 15p. Weather hasn't been too great but got out to little Bernera with it.


Also a few more props to try,
18p merc cleaver (another one)


a cut 15G yamaha, meant to be closer to 16p


And this funky looking thing, 9 3/4 x 17p 4 blade Ron Hill

[Roflhat]

Engine has been running perfectly recently, got the 90hp carbs on too. 99kmph with the modified 15G Yam. Also ordered a new boat, brand new Ceasar F10 from South Africa, should be here around the end of the year. Took a while to decide on colour but in the end I went for all black with carbon nose cone -

(that's not it, but same hull)

Also sending the powerhead to BDK Race Engineering to get it ported and some reed block stuffers. They also might CNC new head chambers for the TSR head.


Tore the whole engine down, and I came across this -

the remains of an exhaust pipe..


So currently trying to have that replicated in stainless. Makes me wonder how fast the engine would go with a functional exhaust pipe!
Think I'll get the whole engine painted while it's apart, all satin black with grey decals, stay tuned...

[Squid Boat]

Really fun and knowledgeable threat mate.

Cheers

[Roflhat]

Originally Posted by Squid Boat

Really fun and knowledgeable threat mate.

Cheers

Glad you're enjoying it!

[Roflhat]

Bit of an update, powerhead is still away getting worked on. Got a new exhaust made, looks the goods and is very similar to the original shape.


Had some time while everything was away getting painted to give the trailer a coat, in black of course. With mudflaps too, going to replace the carpet with black.


Photo of all the props:


The new hull is now finished and on it's way, should hopefully be here in February some time. There's a thunderbolt (5.3m) coming up here too, 90hp yamaha going on it.



Looks alright, but not as good as the F10 Ceasar


carbon nose cone and honeycomb boards


Got the engine put back together today, new mounts and exhaust plate gasket. Whole thing was done in satin black with custom decals

[Squid Boat]

Sick.

Cheers

[fel2]

Did you receive your thunderbolt yet ? Can't wait to see some good picture