Tohatsu M3.5 2006 - Service

[Plankton21]

I've a 13 year old 2-stroke 3.5hp Tohatsu engine that I use on my dingy. I use it for 3 weeks a year and at the end of the season flush it, clean the carb, fog it and change the gear oil and generally look after it. At a guess I'd say it done 130 hrs. It still going as good as new. I'm keen that it lasts as it really light and great for what I use it for. By way of looking after should I be thinking of putting a new thermostat in it? Is there anything else I should do to it to extend its life?

[willk]

Originally Posted by Plankton21

I've a 13 year old 2-stroke 3.5hp Tohatsu engine that I use on my dingy. I use it for 3 weeks a year and at the end of the season flush it, clean the carb, fog it and change the gear oil and generally look after it. At a guess I'd say it done 130 hrs. It still going as good as new. I'm keen that it lasts as it really light and great for what I use it for. By way of looking after should I be thinking of putting a new thermostat in it? Is there anything else I should do to it to extend its life?

I have one as well - similar vintage. I don't see an impeller change on your list but presume you are doing occasionally? I'd imagine every few years should cover you - even though the impeller will be OK, cleaning up the pump assy and regreasing the splines/bolts in the leg is important. I tend to check the appearance of the plug as well and clean/regap if required.

[Plankton21]

Yes, sorry should have said, I've changed the impeller every three years, just done this last week and cleaned and grease as necessary. For the spark plug I tend to stick a new one in each year. Have you ever replaced the thermostat ?

[Plankton21]

For that matter does the 2 stroke 3.5 even have a thermostat ?

[spartacus]

I used to have the same engine as an auxilliary.

There's no thermostat on the 2-stroke version at this size. https://www.tohatsu.com/common/owner...0e78c2fe9f.pdf

Service wise, I know you've done the impeller, did you change the gear oil? Use new fibre washers. I'd check the wiring bullet connectors. They oxidise over time, so pull them apart, light sand with sand paper, and reconnect. Lube grease nipples.

I'd also check the fuel filter near the fuel switch. Personally old fuel can cause issues, so drain and refill. Check the sacrificial anode. Often overlooked, pull, wire brush and refit.

Lastly, change the starter rope. Again, often overlooked.