Its a mystery!!!

[9D280]

Originally Posted by scratch-boy

Dear All,
81 Mercury Blueband thunderbolt,
<snip>
All opinions welcome

There's not a snowball's chance that's an '81 motor. The clamshell (what the Blueband eventuially evolved into) died out in about '82 after much modification (in 1981 it would have CDI ignition). I would hazard a guess at nearer '71 or earlier (Nos, can you confirm?), but having said that if it's a runner don't let that put you off. The good thing about older engines is they are generally less fussty about fuel quality & have a lot less electrical gubbins to go wrong. They are also nice &* light for their size.

Back to the toobs tho' - if you don't get any bubbles, increase the percentage of washing up liquid in your mix. If the leak is big enough and you have a low percentage of soap, it could be destroying the biubbles before they have time to form. I had that on mine - "standard" mix found nothing but a cup full of 50/50 in the area I was sure the leak was and bingo, bubble central.

Boat was, like a skating rink afterwards (my leak was on the inside), so remember to hose it down before you go out! :Thumbs:

[scratch-boy]

Sorry that was a fat finger moment on my part, the engine number is 9252652 so if my research is from a good source the engine is 71, but looks to have been loved. There still seem to be parts about but wanted to check it in the water hence the desire on the tubes.

Good info on the extra washing up liquid, I'll get myself down to Tesco and purchase a case load

[paul tilley]

the worst leak i have experienced was on a new boat that started to leak whilst at a show ,the tube deflated slightly from hard to soft but never went flat approx 3 months later after covering with neat washing up liquid we found a couple of areas where someone had put lots of pinprick holes in it ,possibly an envious competitor of the manufacturer involved or just a dickhead .we never found out who did it but it shows how hard they can be to find

[Poly]

Originally Posted by scratch-boy

the other question could be whether I am better scrapping the hull and selling the motor, trailer etc and looking to start again while adding the money for new tubes but doubt this will stretch to an SR4 which seems to be the choice for a smallish Rib.

I don't know what Paul's quoted you for a retube but unless he was feeling particularly charitable I'd have thought that you would be into the territory of a seaworthy (but old and not spotless) SR4.

Its not impossible for you to make your money back on the boat/engine/trailer on ebay - especially if sold separately.

I might be completely wrong but I would think £2.5-3k would get you a ready to use SR4 with 40+ HP engine (probably with PTT) and servicable trailer?

[9D280]

Originally Posted by scratch-boy

Sorry that was a fat finger moment on my part, the engine number is 9252652 so if my research is from a good source the engine is 71, but looks to have been loved. There still seem to be parts about but wanted to check it in the water hence the desire on the tubes.

Wow, I think I might go buy a lottery ticket! The ironic thing is that I thought mine was an 80s model, but having had it dismantled down to it's piston rings I now know someone put a later livery cowl on it!

I think those engines tend to be either 100% OK or long dead. I don't think there are many "iffy" ones out there, as they tended to die quite conclusivley, so many cooked themselves or gubbed the pistons with too much spark advance. (worth getitng some shrink wrap or tape round the free end of your spark stop screw. Locknut on mine let go & it unwound. The engine stopped as the spark plugs were shorted by the metal that came off the top of the piston at what turned out to be about 38 deree advance!.....

The top cyls on them tended to run a bit lean, I believe if you up the size of your top carb jet by 2 thou' (according to the Ishop parts lists) it helps cure that. If you pull all the plugs, make sure the top one isn't spectacularly less oily than the lower two. (I'm not sure if that problem only happened with the later CDI ignition, so you may be OK, but worth a look) If so, get the next size up jet - they're only about a fiver.

you'd be amazed how many official OEM spares are actually avaialble considering the age of them - and plenty of aftermarket stuff too.

[paul tilley]

i could sell you a 4mtr searider very tatty with 40 hp mariner on a very tatty trailer