Tohatsu 3.5 4 stroke external tank conversion?

[Mg451]

Just acquired a tohatsu 3.5 4stroke it's a 2017. I just put a 6hp carb upgrade kit on it and haven't used it yet so I can't say how long the tiny tank would last but it doesn't look like it'll last long. I saw a YouTube video a guy put a tee fitting in and drilled a hole in the side for the tanks hose connection to fit. But his motor doesn't have a fuel pump mine does. The order of things are..tank to fuel shut off valve to fuel pump to carb. So I'd put my tee before the pump so it'll draw a vacuum to external tank. Just wondering if anyone has done this if the fuel pump is strong enough to draw all that way from the external tank? Or if the primer ball will destroy my fuel pump if I get to pumping it? Any insights?

[maine50]

I knew a Tohatsu 4-5-6 hp outboards were the same motor except the carburetor. Where did you find that the 3.5 could be converted (upgrades) to a higher hp with with a 6hp carb?

[rslifkin]

Originally Posted by maine50

I knew a Tohatsu 4-5-6 hp outboards were the same motor except the carburetor. Where did you find that the 3.5 could be converted (upgrades) to a higher hp with with a 6hp carb?

I've seen 5hp carbs available for the 3.5hp, although I've never seen it actually sold originally as a 5hp. It's a different engine than the 4/5/6.

[Mg451]

According to Google a bunch of places sell the carb and a aluminum prop

https://www.readysetboat.com/tohatsu-3-and-a-half-hp-to-5hp-upgrade-kit-carburetor-and-propeller.html

I went on amazon and got a 6hp tohatsu carb and it fit right on.

Boat Engine 3JE-03200-0 3JE032000 3JE032000M Carburetor Assy for Tohatsu & for Nissan 4-stroke 6HP MFS6C NFS6C Outboard Motor https://a.co/d/fapeGNI

Don't know what the motor did before I got it. Or if the p.o. already converted it but the new one appears ti be the same one i took off it by looking at it. I already had the aluminium prop on so i assumed it was already converted. B
I didn't fuss w the jets etc.

[Mg451]

P.s for any one stumbling on this thread having problems with a 3.5 running there a filter inline inside the fuel line attaches to the upsteam end of the fuel cock. You'd never know it was there.

[tkeithlu]

I don't anticipate a problem with the pump. Lifting gasoline two feet from a vented tank takes about 0.6 psi. If the pump can't do that, it's not a pump. As for the bulb, yeah, that can be some psi applied if you really squeeze that sucker, but if it's a vane pump you'll at worst force gasoline past the vanes, with no damage, and if it's a diaphram pump you'll push the diaphram against its housing. Stop squeezing when you see gas squirt out the top of the carb jets.