1) Any fuel tank that old needs to be replaced no matter how good it
appears to be.
2) Diesel requires a baffled tank.

wrote:
Several manufacturers offer 'Atomic 4 Replacement' diesel engines.
Most are based on the same Kubota 3 cylinder block, the only difference
being the 'marinization' of the engine.
Too, Yanmar has a similar size / weight engine not based on Kubota.

Here's the list;

Universal M3-20B
Phasor Marine P3-20-SM
Beta Marine BD722

Yanmar 3YM20
Westerbeke 20B2 or 30B3
Vetus M 3.09 (Mitsubishi?)

If weight is a concern, the first 3 (the Kubota derivatives) have a
'dry' weight of around 230 lbs. The last three are closer to 290 lbs.

The cost of the basic engine + standard gear reduction (less high-end
meter/light panel or other options) is *around* 6 - 8K$US. Often the
best deals are had at boat shows, so if you're looking to save $,
enquire at a major show. This price does *not* include installation;
you get the engine on a wooden pallet.

I expect that the fuel tank *could* be reused, but only after careful
inspection for corrosion. The shaft and drive train may need to be
replaced, depending on the physical dimensions of the installtion. I
do *not* believe there are *any* "drop in, plug and play" Atomic 4 swap
outs.

MW