Tohatsu 3.5 2 stroke: Using with a remote tank?

jerrytug

jerrytug

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I don't know much about outboards with remote tanks, do they have a little fuel pump in the engine, to suck fuel along the pipe and up to the carb? Or do those rubber bulby squeezers pressurize the tank?
The reason being, I have a motor and dinghy combination I like and would like to go for longer trips, eg all afternoon, without waiting for the engine to die then refilling the tiny tank on the Tohatsu.
I have a strong feeling that I can't just unclip my fuel pipe from the carb, and connect a remote tank, because the engine won't suck up the fuel. Is that right, thanks Jerry
 
Yes bigger outboards with remotes have a pump but, if you mount your remote tank above the outboard, it should work.

The bulbs simply prime the fuel line, they don't pressurise the tank.
 
How about a normal tank position above the engine ( see thats been suggested already) or a T to the fuel line in the engine which you pump petrol back into the small tank on the engine using the squeez bulb from the external tank every twenty minutes or so! You may need to check the flow back to the main tank with a tap as well to stop it draining the tank in the engine, depends on the non return valve in the squeez bulb. In my view you should be able to fill up the small 1 litre tank with a reasonable number of Squeezes, I recon they pump up to 50cc a squeez, not just for presurising.
 
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The problem with a squeeze bulb would be excess pressure forcing fuel past the needle valve in the float chamber, flooding the carb.
You might get away with something like an SU electric fuel pump which stops when the right pressure is reached.
But... that would mean a battery to power the pump.
An easier solution would be to fill toilet duck-type plastic bottles with fuel. Far easier than using a 5 litre fuel container under way. Just take off the cap, squirt in the petrol and continue on your way.
 
The T connection idea may result in overcoming the float/needle valve when you pump the bulb. Which could flood the carb whilst running. Better to drill a hole in the tank at the top, connect the pipe to that and just pump fuel into the tank. But actually better not to at all.

Is it such an onerous task to refuel now and then?

Otherwise buy a 4HP motor with an internal/external set-up.
I'm sure the OP's motor would sell readily and he could pick up a 4HP for £200-300.
 
jerrytug said:
I don't know much about outboards with remote tanks, do they have a little fuel pump in the engine, to suck fuel along the pipe and up to the carb? Or do those rubber bulby squeezers pressurize the tank?
The reason being, I have a motor and dinghy combination I like and would like to go for longer trips, eg all afternoon, without waiting for the engine to die then refilling the tiny tank on the Tohatsu.
I have a strong feeling that I can't just unclip my fuel pipe from the carb, and connect a remote tank, because the engine won't suck up the fuel. Is that right, thanks Jerry
Click to expand...
I know what you mean in that the fuel does seem to get guzzled through the little tank. I just bought a extra 5l plastic petrol can from Halfords etc.. you dont need to kill the engine to top up the Tohatsu tank...just unscrew the cap, surely?
 
There is a risk of fuel vapour trapped in the cowling being ignited if the engine is running.
I know there is in any situation but a ready high voltage spark and an open fuel can is pushing the boundaries a bit.
 
Gordonmc said:
The problem with a squeeze bulb would be excess pressure forcing fuel past the needle valve in the float chamber, flooding the carb.
You might get away with something like an SU electric fuel pump which stops when the right pressure is reached.
But... that would mean a battery to power the pump.
An easier solution would be to fill toilet duck-type plastic bottles with fuel. Far easier than using a 5 litre fuel container under way. Just take off the cap, squirt in the petrol and continue on your way.
Click to expand...

Im not sure there would be much of an issue with the neddle valve in the float tank of the carb as I would advocate only filling up the small tank when the vent is open allowing all excess pressure to be vented out of the tank vent, indeed you may see fuel flowing out of the vent on the tank cap when its full!
I was thinking who hasnt forgotten to switch the fuel of but left the tank vent closed on a hot day, mine seems to cope with it.
 
Lakesailor said:
There is a risk of fuel vapour trapped in the cowling being ignited if the engine is running.
I know there is in any situation but a ready high voltage spark and an open fuel can is pushing the boundaries a bit.
Click to expand...

Yes you see, that's what I feel as well, and refuelling an outboard is a serious operation, because I am leaning over a nearly red hot engine, pouring hot fuel into it, and the dinghy is bobbing about, I need 3 hands, some always goes in the river and some on the engine, and a bit on me, if the fuel did catch, I would be in a bad position.
I give up on the idea of improvising a remote tank, it would be better to get an engine designed for one, thanks for your suggestions Jerry
 
I just got this, with alternative supply choices (that's the tap aft of the gearlever) for £250


Yamaha401.jpg
 
Lakesailor said:
There is a risk of fuel vapour trapped in the cowling being ignited if the engine is running.
I know there is in any situation but a ready high voltage spark and an open fuel can is pushing the boundaries a bit.
Click to expand...
Wouldnt you have cowlings constantly being blasted off then ? I see your point that you have an added risk if you have an open 5l fuel can too... Ok. Switch it off for 15 seconds .. it doesnt take long to pour 1.25l of fuel.
Admit, £5.50 can does it for me , even if I might be advised to switch off.
 
You should get 1 hours running out the in built tank at full tilt.

I have a pouring spout that stops when the fuel gets to it top very little spillage... I would just fill after every long usage...
 
gjgm said:
Wouldnt you have cowlings constantly being blasted off then ? I see your point that you have an added risk if you have an open 5l fuel can too... Ok. Switch it off for 15 seconds .. it doesnt take long to pour 1.25l of fuel.
Admit, £5.50 can does it for me , even if I might be advised to switch off.
Click to expand...
You do it however you wish. There isn't far to run in a small dinghy. :D

There is way more vapour swirling around as you pour the fuel than after you have finished and screwed down the cap etc.

Usaully a flash over will just be a bit of warmth around the engine. In sunlight you may not even see the flames.
I have seen a chainsaw engulfed in flames whilst refuelling.
I also did inadvertantly set fire to a motorcycle fuel tank (mounted on a grass-track racing car) whilst stick-welding. It was like the biggest Roman Candle you have ever seen.

These days I like to keep fuel and sources of ignition apart.
 
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