What would be symtoms of stale fuel in a Four Stroke?

[odes20]

Heard about stale fuel as an issue over the years but Ive never had any problems that I have been aware of..

Recently added 85 litres to my tank to go out. Got a big back fire in Suzy 175 at start up in the water to get off the trailer. I had a friend say it was prob stale fuel, but I had added a lot of fresh fuel. The boat had sat idle for about 3 months before hand though.
Appreciate hearing any experiences or info.

Cheers
John

[Spaniard_King]

did the engine run ok after the backfire??

usually a back fire is a result of too much fuel in the inlet manifold from a leaky injector or no spark and a build up of fuel vapour.

Wouldn't think stale fuel would do it.

[odes20]

Yep ran fine and has done since both from cold and when hot.

[Giffo65]

The 4 stroke motor had a dream and thought it was an Etec, and nearly choked in disgust, causing the backfire ! lol
(Giffo now dons helmet, awaits return fire )

[bigpat]

Giffo, you crack me up!
Any 4 stroke injected engine can backfire, I've had our Aurion do it on startup, and racing engines I worked did it often. I wouldn't really worry about it. Normally happens in the exact conditions you had. Computer senses low water temp, and goes into fuel enrichment mode( similar to choke) on start up, so a lot of vapour in the chambers and inlet runners.......

That's exactly why carburettor inboard engines run air filters, though they specifically call them flame arresters.....

[Apollo]

Motor enjoys a good fart in the morning. Nothing wrong with that.

[Fed]

A sneeze or a fart?
Maybe all the Suzuki failing exhausts aren't from corrosion at all, just huge farts.

[odes20]

Just a fart hey? Im happy with that. I love my Zuke, so much so a fart wont be a turn off at all!