Leaky 2.5 tohatsu fuel cap

[stuartwineberg]

Posted this by mistake on the liveaboard site - no wonder I didn't get a reply!

Further to a recent post, my trusty Tohatsu which normally lives on its side has, after a winter stood upright started pouring fuel out from under the filler cap when tilted. There is no apparent damage to the tank and I have first replaced the funnel shaped main seal in the cap and then replaced the whole cap. Before I dole out for a new tank am I missing anything obvious? I was thinking of trying to put a fibre washer in there or even carefully running the top edge of the filler neck of the tank on fine wet and dry to make sure it is flat. I can't see that it is anything but a warped top edge of the tank filler neck. The only clue is that the bloke at the service place said they sell a lot of tanks for this model but aren't sure why

 

[morgandlm]

I had to replace the tank on my outboard due to a leak in the join between the threaded collar and the tank itself. I think probably the result of over tightening or maybe just a design / stress problem. Have a close look at the tank. The replacement tanks are silly money!

Morgan

 

[doug748]

I had exactly the same problem on my old 2 stroke 2.5. I never did solve it but learnt to keep the tank half full and store the thing at an angle. I began to suspect that the tank was split at the neck, there appears to be a seam but I guess if is really a blow moulding flash. If the tank were split it could probably be welded.

You might test the tank by pressure or holding it upside down against your palm (smelly and awkward though)

I would love to know the root of the problem, keep us posted.

 

[NormanS]

I had the same problem with a Mariner 2.5hp two-stroke. I have to transport it in the car boot, so it mattered. I couldn't see the cause of the fault. Tried a new cap, - no better. Eventually replaced the tank, with IIRC a Tohatsu one. It seems that these little outboards are pretty much the same with different badges.

 

[stuartwineberg]

Thanks all - good to know I am not alone. It really does seem to be coming from the cap/filler join, not the filler neck/tank join. I have taken all the cowlings off to make sure it isn't a leak elsewhere. I think the winter temp changes have warped the plastic so I am going to go down the flattening the surface - poss adding a fibre washer route. Will let you know if I resolve it - take silence to mean I had to fork out for a new tank!