Introducing The Smaller Nashers 380 Aerotec

[Nasher]

Grabbed a couple of hours working on this engine yesterday afternoon.

My initial assessment still holds, in that it’s actually in reasonably good condition, and the friend of the last owner who took it to bits to investigate did a good job of keeping everything.

Luckily all of the head bolts had come out in one piece, a real result on a Suzuki of this age that were put together with chocolate fasteners.
Unfortunately 9 of the 12 M6 bolts holding the exhaust cover plate on the side of the main block had sheared off so needed some TLC.

I tried welding a nut to each one then cooling them rapidly with water, but each one sheared off lower down so I needed to get serious.
Having the block completely stripped and on the bench was a real bonus as I could level it up in my milling machine and mill the remains of the studs off level with the face of the block then drill them out. Luckily I had the correct size Helicoils in the garage, so after giving the block a good clean and smothering the bores in grease to protect them it’s now ready for reassembly.
There is not the slightest hint of a wear ridge at the top of the bores, so it can’t have been used much since it was built in 1984.
When I put it back together I’ll use std size pistons ad rings but put a ‘glaze busting’ stone down the bores to deglaze them.

All of the parts needed are still available, so I’ll be placing an order on Browns Point in the states over the next couple of days once I’ve had a better chance to look for new old stock parts here in the UK.
I’ve already purchased NOS Small end bearings and Gudgeon pin Circlips from a motorcycle shop on ebay for a total cost of less than £10, so I’m off to a good start.
It looks like those are the only parts that carried over from motorcycles so the rest are outboard vendors only.

Nasher

[Nos4r2]

Nice one!

[Nasher]

Originally Posted by Nos4r2

Nice one!

I’m hoping my early bought of feeling smug isn’t going to be brought down in flames.

I did very briefly consider breaking it for a profit, but can’t bring myself to do it.

Nasher.

[Nos4r2]

If you REALLY want the smug feeling to stay, take the crank to a bike shop and get them to press it apart and put a new set of bearings in It should still be a cheap motor afterwards.

[Nasher]

Realised I hadn’t updated this thread with the results of our mucking about with the DT15.

It’s now in one piece having been rebuilt very slowly over the last couple of months as and when funds were available.
It stands us at under £330, not including our time of course.
Nearly all the parts have been ordered and delivered from the states due to the much lower costs.

So apart from cleaning it what did we end up doing?

Lower unit.
New Impellor.
Lower Impellor housing – Repaired.
It was badly corroded so I ended up boring out the centre and machining up a new centre which I pressed into place.
Complete set of new bearings, thrust washers and spacers.
Fresh Oil

Mid section.
New Knob machined for the tilt lock mechanism.
Good clean and grease of everything.

Powerhead
Block stripped back to a single component for cleaning etc.
New Main Bearings, Little ends, Gudgeon pins, Wrist pins, Pistons, Piston Rings, Crankcase seals.
De-glaze the bores.
De-scale waterways.
Helicoil all the 12 Exhaust side plate bolts.
Clean Carb.
Complete set Gaskets.

For the future I’ll Carbon wrap the hood so it matches the DT200EFI on the RIB, but for now they are just going to enjoy it looking a bit ‘Shabby Chic’.

Oh and by the way.

IT RUNS

It's nice and quiet and pumps loads of water.

Nasher.

[Max...]

Nice one Nasher - having had a few SIB's I think the Aerotec/2 smoke 15 combo is about as good as it gets in the all round portable/capable/cost/weight fun boat for £'s (and lbs) you can get.

[Nasher]

Thanks Max.

As soon as I know the 15 is good out on the water I'll probably be able to offload the 9.9 for more than the 15 has cost us.
Win-Win

Nasher.

[Nasher]

One interesting thing I discovered last night is the minimal weight difference between the 9.9 and the 15.

They are completely different physically as at that point in history the Suzuki 9.9 and 15 were not based on the same block, and the 15 being older is a slightly different design. The 15 is physically bigger but only 3kgs heavier when weighed on our bathroom scales.

DT9.9 - 32Kgs
DT15 - 35Kgs

Some of the difference is due to the Autolube tank under the hood of the 9.9, but that only holds about 1L of oil.

Nasher