Tohatsu 9.8 MFS (maintenence/storage)

BananaMan

Cadet
Joined
Jul 24, 2023
Messages
16
Hey everyone!

I just purchased a brand new Tohatsu 9.8 for my 12 foot vhaul princecraft.

Just finished reading through my owners manual. Though I would pop in here and see if there were any tips/tricks from the community as far as taking care of the motor and ensuring it lasts a life time.

A few things I plan to do.

1. Ensure I am adding a fuel stabilizer with each tank I burn. (Any recommendations on which fuel stabilizer is best to use?)

2. In the manual it mentioned if you can't purchase ethanol free fuel, to use a filter that separates water. Would this be necessary if using a fuel stabilizer?

3. Long term storage (5-6 months) My thought is to unplug the external tank and let the motor run out of gas while idling. Anything else I should be doing ?

4. Obviously will be changing the gear oil and engine oil as necessary as well.

Thanks in advance for any and all advice.
 

MattFL

Master Chief Petty Officer
Joined
Oct 20, 2010
Messages
856
Really make an effort to find ethanol free fuel, it does make a big difference in how well it stores. I've used StaBil with success, probably any big name brand is OK, but in my experience, strait ethanol free fuel seems to store better than ethanol fuel with stabilizer. Ethanol free fuel with stabilizer stores the best. I'm in S. FL where it's humid. Here if you leave ethanol fuel in the carburetor for even a couple of weeks, it clogs up the tiny pilot jets on small motors, even with stabilizer.

Generally speaking, a fuel/water separator on a boat is a good idea. With small motors they're not always used because the fuel tanks are typically smaller and portable and it's just inconvenient. If your tank is permanently mounted to the boat, or if you have a convenient place to install one, it's a good idea. However plenty of small motors are run without fuel/water separators, just be sure to keep the fuel fresh and water out of the tank. Ethanol fuel is more sensitive to water because the ethanol absorbs water and it makes the fuel gummy and corrosive, and it turns visibly yellow. If it absorbs too much water, the ethanol will separate from the gas. This is my guess as to why they want you to use a fuel/water separator with ethanol fuel specifically.

For storage actually drain the carburetor if it has a drain plug. Even if you run it dry, often there is fuel still in the bowl that can be let out with the drain plug. After draining, pull the rope or hit the starter so it sucks any tiny bit out of the jets in the carburetor. If you use the motor in salt, be sure to flush it after every use and consider spraying it under the hood with silicone spray, this stops corrosion.
 
Last edited:
Top