Yamaha F70 Fuel Tank Deformed

[chrisleighbrowne]

I spend a day on my RIB yesterday and went to re-fill after use. I noticed the Yamaha red fuel tank had deformed as though the petrol was fighting a vacuum. When I opened the filler cap/gauge it restored its shape a little but not completely. Any ideas would be gratefully received.

[rkk01]

Breather blocked or closed...?

[chrisleighbrowne]

Not sure where is it located? Sorry fairly new to boating!

[charliee]

breather not fully open - lucky you didn't conk out.

[rkk01]

Fuel tanks need to allow the air to enter as the fuel is drawn in to the engine - i.e. to prevent a vacuum forming and eventually starving the engine... but, at the same time, you don't want your fuel to spill when moving the tank around, or to evaporate away when stored. Mine has a small breather on the filler cap, with a grub screw for "open / run" or "closed /store".

There's been many occasions when the engine has got a bit "lumpy", or has cut completely, and it's because I've forgotten to open the breather valve

[Wightdiver]

Originally Posted by chrisleighbrowne

Not sure where is it located? Sorry fairly new to boating!

Usually a small screw/cap on the main filler cap.

[chrisleighbrowne]

Thanks, all will check this - not been pointed out to me previously though I'm amazed I was under power for several hours with no issues!