Tohatsu 3.5 rebuild

M

macd

Well-Known Member
Joined
25 Jan 2004
Messages
10,604
Location
Bricks & mortar: Italy. Boat: Aegean
Visit site
I'm just completing a rebuild of a Tohatsu 3.5B2 (new main bearings and seals). It occurs to me that with these 2-strokes beoming unobtainable in Europe, plenty of such rebuilds might be going on in the coming years. So, I'm just putting the fact of this on the YBW database, as it were, should anyone wish to pick my brains in the future.

It's a straightforward job requiring no special tools, well within the province of a handy amateur.
 
Hi
out of interest as I have one of these engines and have so far been really pleased with it - how many hours/period of use before needing the bottom end rebuild or was this due to a mishap/accident such as running without lub oil in the fuel?
 
Hi to you, too.
I don't think hours is a particular issue. Whatever the brand, most probably succumb to corrosion or abuse in one way or another -- in my case getting dunked. Although I thought I'd cleaned it out adequately, I was obviously mistaken. But the engine seems pretty tolerant, since it soldiered on for another 2 years with just increasingly rattly main bearings (which I lived with, promising myself I'd fix them 'one day'. In the meantime I increased the lube from 50 to 40:1).
Recently the revs showed a tendency to rise on a fixed throttle positon at moderate to high revs, which told me a crankcase seal was on the way out (so the engine was drawing in air from somewhere other than the carb....so running lean...so in danger of detonating to death).
I think if they're serviced and used regularly, they should last for aeons. If it ain't broke, just keep using it...
 
I bought a new 2-stroke just in time for the very reason that they are all so simple to work on. OK, I'm just as happy to work on a 4-stroke and they're are certainly more efficient and eco-friendly .......but a lot more bother. especially if dunked and a pain when transporting in the car with oil everywhere.

The lawn mower is 4-stroke because in that application it makes sense.

Vic
 
I've just replaced the bearings and seals in an old Seabee outboard. I got the parts from simplybearings.co.uk. I have noticed with my 'modern' outboard motor (Crescent 3.9) that the uppermost main bearing suffers from condensation when the outboard is stored in the shed - so hang an old coat over your engine when its not in use!

Neil
 
You must log in or register to reply here.

Share this page

Top