Tohatsu 18hp lower casing

[topshelf]

I have managed to crack and hole the gearbox casing on a tohatsu 18hp 2006 model , four stroke. If I can get a casing is it a easy job to switch parts over? Do I need special tools? I have a basic knowledge of engines but never done any thing like this. Is there a book/ manual that will give pointers? I haven't taken it to my local marine shop yet as I'm still away on holiday. I am prepared for cost of casing and shop fees meaning its a write off .

[Fenlander]

Yes it's a faff as you will likely need pullers and the ability to set up clearances. Normally folks would look at buying a complete used gearbox.

At the very least I'd want to see the makers repair manual check exactly what's involved before buying a casing.

[Choppergeoff]

Google the engine for a manual, and print it off. I have a 15hp Parsun ,which is akin to Yamaha and possibly others. They are readily available.

[gaelforce]

I had a j crack on my honda 50 casing. I tried epoxy, didn't work. Got it TIG welded and no trouble since.

[topshelf]

Hi, Update, So I collected it today, they have replaced a gasket that goes between the power head and engine casing, it showed signs of fluid passing into the exhaust, so we think it was the engine oil running into the exhaust then out the bottom, will see next week when its stood upright in my garage for a few weeks. I still cant get to grips with downloading a photo on here ,sorry.

[spartacus]

These really are separate faults. If the engine is losing oil, then assuming this was impact damage that fault may or may not be resolved with gasket for the power head.

There was a useful video from Stu recently on his Dangar Marine YouTube channel about an oil leak due to corrosion on a Yamaha F70. That was fairly involved and there was hoists, TIG welding, the works with guys who do this for a living.

The leg then if it’s holed on the gear box, then potentially it can be welded, but you’re looking at rebuilding the drive shaft and prop shaft with new seals which is no mean feat, as you need to use shims to get everything set up within tolerance. Assuming the engine oil issue is resolved, I’d be looking at a second hand leg rather than a strip and rebuild unless you’re spanner handy and have access to the technical literature for the engine.

[topshelf]

Thanks Spartacus, having had my panic head on after I noticed it I saw what looked like a crack to the shaft from the outer casing and a hole that I had not noticed before. it turned out the crack was just paint related and the hole was a drain hole for the lower casing, I had my panic eyes on, the engine oil was leaking through the gasket and into the exhaust , this in turn ran down the leg and exited through this hole that I had not noticed before. will see after the weekend if it has sorted it.
cheers