On 2 occasions our Tohatsu has stalled after running for approx 20min. The priming bulb has been empty and we have had to keep squeezing the bulb to keep us moving. I thought it would be something like a blockage in the line or the valve in the fuel tank cap hasn't been opened. When checked the valve has been loose. Not as loose as when first opened, but loose enough. I will check for a blockage later this week.
Is there anything else I should check while I have it off the boat?
Cheers

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valo said..
On 2 occasions our Tohatsu has stalled after running for approx 20min. The priming bulb has been empty and we have had to keep squeezing the bulb to keep us moving. I thought it would be something like a blockage in the line or the valve in the fuel tank cap hasn't been opened. When checked the valve has been loose. Not as loose as when first opened, but loose enough. I will check for a blockage later this week.
Is there anything else I should check while I have it off the boat?
Cheers

Its not difficult to take the cover off and then four screws to undo and clean the carb.
That will eliminate one possible problem and your boat should run better.
You might get a surprise at how much gunk is in there.
Alternately it does sound like a fuel issue so was the valve in the cap open enough?

If the priming bulb is emptying then I would suggest that air is leaking into it, and that a new line, bulb and filter each year or two is good practice. Lines also deteriorate in the sunlight, so a new line would help. And it'd only be $20 to replace.
The motor runs so that's fine unless the carby is dirty. It seems to be a fuel problem upstream from there, so a line replacement/change. You could also empty your tank and rinse with metho because you might have water there too. Last year my mechanic found teaspoon worth of water in the tank.

Thanks.
Forgot to mention that I only had it fully serviced and the water pump impeller replaced about a year ago. It has little use since then.
I will check for cracks and clean out the fuel tank as well.
It isn't the valve in the cap, as last time I opened the cap and left it ajar and I still needed to squeeze the bulb. I will strain the fuel in the tank to see if it has anything in it that could block the hose.
Cheers

Many years ago I had the same problem with a Johnson 6. It had a small internal fuel pump which needed to be replaced.

You also need to clean the fuel needle. 1-19

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Yara said..
Many years ago I had the same problem with a Johnson 6. It had a small internal fuel pump which needed to be replaced.

Thanks Yara. I'll check it. However the mechanic said it was in good nick when he did the service.

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nswsailor said..
You also need to clean the fuel needle. 1-19

Thanks. Will do.

Fuel pump diaphragm split or just baggy...

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Jedibrad said..
Fuel pump diaphragm split or just baggy...

Thanks

Sounds like a similar problem I've had before, and found it to be as Fphil said, air getting into the system, I had to replace the fuel male fitting on the outboard motor, was about $12, easy as and fixed the issue.

Just had a similar problem on my 4 stroke where pumping helped keep it going, but only at idle. A small, internal split where the hose met the motor. Replaced hose and all better.

If its not been used for 12 months it will almost certainly need a carby clean and check the fuel pump while you're at it.
my experience is that sort of thing is almost always the carby.

If the bulb is full of air, it's pulling air from the tank. I had this issue years ago and the problem is air being drawn between the tank and the hose. I think from memory it was a loose pickup tube in my case.

Had the same issue on my 4 stroke 5HP caused by dirty inline fuel filter. It was 2 years old but only had a few hours on it and didn't expect it to be the cause. Not sure if it was crap from the fuel tank or algae that grew in the filter that blocked but after that I got 2 lots of 10 6mm motorbike filters from ebay and now always carry a few spares on the boat. I ordered both the paper and the bronze type to try them out and both seem to do the job the same and at less then $1 each I change them every 6 months or so.

Thanks for all the suggestions. I still haven't had a look at it yet. Was going to on the weekend. Not game to now in case I get caught. Even though I would not be touching anything other people touch, or be anywhere near anyone. I'll just go grocery shopping instead. Much safer.

I had a Tohatsu 5hp 2st and it never let me down. Serviced it every year - it takes about 15 minutes - and it ran faultlessly.
Fuel?!
One should not, but many do, use that rubbish concoction called E10! Did you?

It caused my carby clog up - on my bike - with resiny yellow-brown gunk which hardened and also caused the rubber bits become like soft dough.
After re-building it l used only normal unleaded or better, but E10.