My thundercat

[Roflhat]

Originally Posted by tinker

Great photographs, what camera do you use?

Just my iphone, whichever number it is maybe 13? The drone shot isn't mine, that was taken by James Booth

[RickW]

How big is the fleet now I am losing track!

[tinker]

Well there very good, suppose the location helps.

[Roflhat]

Originally Posted by RickW

How big is the fleet now I am losing track!

Sold the blue one, so currently 3 cats although selling the Black ceasar. May also sell the yellow one to be honest, it's great fun but once you're used to a regular sized thundercat it doesnt quite scratch the itch

Originally Posted by tinker

Well there very good, suppose the location helps.

Thanks, yes as you say probably hard to get a bad photo when the suns out in Balfours Bay!

[Roflhat]

Despite having the dullest June on record got out a couple times



Can't believe it's 10 years since I started this thread

[Steve509926]

Happy 10th year anniversary

Lovely pics.

[Roflhat]

Originally Posted by Steve509926

Happy 10th year anniversary

Lovely pics.

Thanks, doesn't feel like that long!

[Roflhat]

Considering moving from the 70hp Yamaha down to a 50hp. Was even thinking of going to a four stroke, Tohatsu 50hp being the lightest.

Did a speed run or two towards the end of last year, only up to around 58 knots but felt real fear for the first time on the thundercat. Wasn't sketchy or anything just concerned about damaging my spine again. It still pops audibly 4/5 times a day when I stand up, not painful but it never used to do that pre Coniston '21.

Shame as I'd still love to hit 70 knots/80mph but I do feel I would need an active front wing in order to keep the boat stable at those speeds. I did continue developing it with help from a few folk but it's complex.

For now just happy using the boat for fun and various adventures, which is why I'm thinking of going to a 50hp. Haven't gone anywhere near full throttle with the 70hp for ages now. Also doesn't have tilt which would be handy, and having to remove the cowling to start the engine each time is a little annoying. I could change that but putting chokes back in the carbs but seems a shame to detune the engine which runs absolutely brilliantly.

[Fenlander]

Stunning images.

I'd reinforce the view... look after your back.

From 40-55yrs I took chances over-lifting farm equipment with several instant punishments for doing so. Added to near on 20yrs shifting thousands of hay and straw bales each year by hand the wear and tear means I have to be very careful what I move now in retirement affecting the size of OB I can manage amongst other things.

[Roflhat]

Couple shots from recent camping trips out in the boat. First photo is at Campay just north of Little Bernera. Can fit through that arch on a calm day.
Second night I wished I'd taken a bigger anchor, would've slept better for it




New engine, going to try it out on the old blue Ceasar to check it all works as it should. Will get the head skimmed at some point, but will be able to run regular 95 octane in this one. Yamaha 50hp 2 stroke, 1997. Not sure if I'll sell the 70 though, such a brilliant engine

[Roflhat]

Got the 50 up and running. Had to machine an aluminium spacer and a plastic bush which were missing from the tiller assembly, made them up on a lathe.
Ran up alright but not perfect and took a lot of pulling. So pulled the carbs off and cleaned them, changed the fuel pump and cleaned out the filter. New set of plugs, started and ran better. Need to get her out on the water, have put it on the old blue cat for testing.

Will probably skim the head 1mm, need to do a squish test. The block is 6h4 which is 40hp, but the carbs look to be 50hp and the opening has been radiused with a dremel at some point so presumably ex race. Hoping it's still got the 50hp exhaust tuner, can't imagine anyone would bother changing that to a 40hp one when they changed powerhead.

Nice to have an engine that tilts up!

[Roflhat]

Tried the 50 out today, unfortunately it runs terribly. Takes a lot of pulls to get going then cuts out in gear and won't take any throttle. Pretty sure there's some bearing noise coming from the crank too. Going to pull it apart and rebuild it, was probably going to do it this winter anyway so not too big a deal. Will do a couple of tweaks to get some better flow out of it but nothing drastic

[smallribber]

You certainly like messing with outboards.... Don't blame you

[Roflhat]

Any excuse to pull a 2 stroke apart and play with it!

[Roflhat]

Pulled the Yamaha apart today, everything is in really nice condition no broken bolts or nasty surprises. Powerhead bolts were definitely not torqued, barely even tight in fact so opossibly an air leak there.
Bottom bearing on the crankshaft is a bit noisy so it was that I was hearing. The others fortunately are alright so that saved a chunk of change not requiring a crank rebuild. Pistons are 0.50mm oversize and the ports have been played with but look ok.

Made up earth wires for the coils, did this on my 70 and never had any issues with them since. Removed the temperature sensor and some other sensor from the cylinder head


Head before, taking it to get machined down don't know how much but so the beginning of the squish band is flush. I reckon it's around 1mm


Very very clean for a 1997 motor, even the paint is pretty good. I've put new control cables on already, old ones were split and rusty. Also new clamps for them, instead of the DIY bracket that was holding them on


I've ordered new decals for the cowling, the newer mid 2000's onwards style. Pretty sure the paint colour is the same or very similar so should look alright.



Was going to take the exhaust out and maybe modify it but the engine mount bolts are well stuck. Engine mounts look alright anyway so going to leave that all as is.

Also ordered a set of Boyesen carbon reeds, wasn't going to bother but don't want to do all this and then have a steel reed break and end up in a cylinder

[Roflhat]

New stickers arrived for the cowling

[Roflhat]

Found a wire from the trigger coils to the CDI that wasn't connected which explains the poor running - only on 2 cylinders of the 3

[Fenlander]

>>wire from the trigger coils to the CDI that wasn't connected

One of those lucky day moments that don't come often, hope it does sort it.

Are the stickers a thickish vinyl or more of a transfer than needs a clear coat over?

[Roflhat]

It’s one of those problems I could have spent weeks chasing, glad I took the engine apart now.

They’re pretty thick and good quality stickers, got them from outboard graphics.com
Seem close to genuine

[Roflhat]

Got down to Taransay yesterday, a bit fresh on the way out F5 but had a fantastic time

https://www.youtube.com/watch?v=CTBWPLbKRYo