merc 4.3 fuel prob

[mkfs9]

Hi all not been here for ages but here's the problem. Boat runs fine for hours steady cruising around 18 ft 1988 searay seville . Seems when we get to half a tank the boat starts to die sometimes stall.starts up straight away though every time. Once this starts it seems to continue but will idle oblong just fine. Breather is fine, checked non return valve on tank seemed clear and functional..any help would be great.five days in a row so something going on thanx from the UK

 

[Fun Times]

Re: merc 4.3 fuel prob

Welcome back! Sounds like you may have an issues on the inside of the fuel tank and if so, hopefully it's only the fuel pickup tube.

The problem could either be the fuel pickup tube screen located at the bottom of the pickup tube is getting clogged up with debris floating by as the fuel level gets lower or you may have a cracked pickup tube that is sucking air as the fuel level gets to a certain spot while on plane vs off plane and the fuel level recovers the crack so not to suck air allowing you to idle home. The pickup tubes are like a plastic type material that could crack.

Also it's important to know what type of material your fuel tank is made out of, as some of today's fuels could start a delamination process to some older fiberglass fuel tanks.

 

[mkfs9]

Re: merc 4.3 fuel prob

Thanx for the reply. Aluminium tank and non return valve which I have checked and seems clear and free. As said with a full tank can plane at modest speed 25 /30 mph for hrs then the boat will hunt bog down sometimes stall. But starts up instantly on the key.

 

[mkfs9]

Re: merc 4.3 fuel prob

Any tips on removing the fuel pick up assembly would be appreciated.

 

[Bt Doctur]

Re: merc 4.3 fuel prob

post some pics. some are welded in place.