Tohatsu 18hp 2-stroke – Simple self-service

[wxmrich]

I’ve been using my Tohatsu engine for over 12 months now and so it could do with a service.

Only problem is I want to start using it in the coming few weeks but can’t really afford a full dealer £100 service, at least not until the summer months anyway!
Could anyone tell me the simple procedures I could carry out at home with basic garage tools and the engine handbook?

I’ve so far planned the following:
- Replace spark plugs (bought from eBay)
- Clean oil filter in engine
- Clean fuel filter in fuel tank
- Replace old fuel in fuel tank
- Possibly replace impellor (no idea why or if this is essential)
Engine was fully flushed and fuel ran out before winter storage in garage wrapped in a duvet!

Any further advice and tips would be great.
P.S on my last outing the engine took about 7 or 8 cord pulls before it started compared to the usual 2 or 3 (1 when warm). I presumed this was a spark plug problem for it to change in the space of a month or so?

Thanks!

[spartacus]

Gear oil needs changed regardless of hours if it's been 12 months. You can get new Tohatsu washers for the fill and drain plugs from a dealer. Inexpensive but worth changing if current washers look tired. Yamlube or Quicksilver gear oil is perfect.

The impeller can be changed every other year. I used to do it annually but have moved to every 2 years. Again this is personal choice, but if in doubt as to when it was last changed, then do it. There's a woodruff key on the drive-shaft, so grease this before seating the new impeller. Remember to grease the water pump housing lightly and turn impeller clockwise. Grease the gearbox bolts before reattaching.

Pull-start cord. This is my take on it - it's difficult to determine condition purely by visual check. I'd replace so you know its good for the season. Bit fiddly but easy enough once tension on pull cord spring has been isolated.

You can check the thermostat. You'll need a new gasket if you remove. Again, relatively inexpensive to purchase. Sometimes the water channel here gets salted up, and good opportunity to inspect condition.

Electric wise, check the bullet connectors for tightness. You can lightly grease the male and female connectors.

Get yourself a grease pump and grease all the nipples on the outboard.

Check the zinc anodes on the outboard. Replace any if particularly corroded. Might be a small one inside thermostat housing, under the anti cavitation plate near the propeller, and one under the outboard saddle.

Remove propeller, check rubber bushing condition, grease prop shaft, add castle nut and thrust washer. Use a new stainless steel split pin.

[Locozodiac]

No need a impeller change, Tohatsu's impeller happens to outlast any other brand on the market due to being elastomer made as opossed to plain rubber found in almost all other OB brands.

As stated change gear box oil with SAR 80/90, 90 grade good quality brand gear oil, well gapped factory recommended spark plugs heat type.

Apply a few droplets of thin oil on choke internal plate's shaft at both sides of carb, with time and use sometimes tends to stick and when choke knob is pushed all the way in plate will not be left at 180° fully opened position inside carb's throat. Oil both extremes of butterfly's shafft too at both sides of carb and arm's white roller shaft.

Lube all sliding and rotating parts specially the whole throttle area for smooth and long lasting plastics parts operation. Remove prop and grease well prop splines

Tohatsu dealer should torque cylinder head and exhaust cover as well when engine is new right after 50 + worked hours, all boaters preforming DIY works skips this which is mentioned in the tech service manual.

Happy Boating

[wxmrich]

Cheers chaps. Looks like I'm gonna need a lot of grease!!

[Flyguy]

I'm being quoted £150 for a service on my Tohatsu 9.8 2 stroke so I want to learn how to do it myself. I have the service manual but doesn't give step by step instructions.
Can anyone suggest the best place to learn to do DIY service?

[Locozodiac]

2 strokes engines needs very little service compared to 4 stroke brothers. If you want state of the art service install an induction hour meter inside cowl. Change spark plugs, gear oil, internal filter clean out every 100 worked hours. Impeller is other story, do last very long compared to other brands. If you don't want to clean carb frequently, run bowl dry after each outing, disconnect engine fuel hose and let engine drop dead.

Fill hydraulic red oil into a small syringe, apply tiny oil droplets onto all rotating parts specially on throttle system each 100 hours too.

Happy Boating

[Flyguy]

Thanks Loc. Service bits ordered.