Drift boat motor repair

MT406 · Dec 24, 2023

I purchased a second hand Tohatsu 3.5 4 stroke motor. By the end of summer, it was having problems with idling and throttle response. I’m by no means a mechanic, but could this be possibly due to a gummed up Carb? If that’s the case, how many hours should it take for a mechanic to clean it?

Will be using non ethanol gas moving forward.

Pescaphile · Dec 24, 2023

It should be a very quick job to remove a carb, clean it and open up any blockage(s) in the jets. I don't know about your specific motor, but I've been able to do it in 1/2 hour on a both a 4hp Yamaha and a 2.3 hp Honda. I'd expect no more than 1 hour labor charge from a mechanic for this.

In the future, make sure you drain the carb before any longer layups (more than, say, a week). The non-ethanol gas will help avoid these problems as well.

MT406 · Dec 25, 2023

Thanks. I figured it shouldn’t take too long.

Billy · Dec 25, 2023

Does it run fine at all? Full tank of gas how does it run and idle?

MT406 · Dec 25, 2023

It’s always been a bit erratic and a bit of a pain to start, even with a full tank. I’m hoping it’s due to using ethanol gas. Which I won’t make that mistake again.

SurfnFish · Dec 25, 2023

first thing I always advise when small outboards have these problems is using Sea Foam.
Also a great product to run thrugh any outboard yearly.
For specific 'problem' treatment

https://seafoamworks.com/uploads/2018/12/HOW2_Outboard-Can-Hose-Method.pdf

BCO · Dec 25, 2023

MT406 said:
I purchased a second hand Tohatsu 3.5 4 stroke motor. By the end of summer, it was having problems with idling and throttle response. I’m by no means a mechanic, but could this be possibly due to a gummed up Carb? If that’s the case, how many hours should it take for a mechanic to clean it?

Will be using non ethanol gas moving forward.

First thing for idle issues is replace the spark plug with a properly gapped plug. Check the coil output and flush the fuel system with SeaFoam. Small displacement engine’s that are run at low rpm’s for long periods need periodic checkups.

Chucker · Dec 25, 2023

MT406 said:
It’s always been a bit erratic and a bit of a pain to start, even with a full tank. I’m hoping it’s due to using ethanol gas. Which I won’t make that mistake again.

Don’t pin all your hopes on it being the ethanol in the gas, newer motors are totally fine with it.

SurfnFish · Dec 25, 2023

btw, cleaning whole carbs in an ultra sonic cleaner is the go to forservicing OB's, motorcycles, snowmobiles, lawmowers, etc...Harbor Freight sells them for cheap.

John Svahn · Dec 25, 2023

I have a 20 year old tohatsu 4 stroke and it became erratic at the throttle. Wasn’t the throttle, it was a loose plug wire. Fwiw.

Squatchin · Dec 25, 2023

Good opportunity to upgrade the carburetor and prop to make it a 5hp

Tohatsu 3.5HP to 5HP 4-Stroke Upgrade Kit (Carburetor and Propeller)

This kit converts 3.5hp 4-Stroke Tohatsu outboards (2006 and Newer) to 5hp. It includes the 5hp carburetor as well as an aluminium propeller to take advantage of the extra horsepower. If you already have an aluminium propeller instead of a plastic one, you can simply order this 5hp carburetor...

www.readysetboat.com