Suzuki dt20 fuel problem

"i have a 1988 dt20 3 weeks ag

"i have a 1988 dt20 3 weeks ago it would not start at all, after checking all the obvious, in my wisdom i took the fuel pump off checked and refitted. still would not start, made a cuppa pondered then tried it again and hey presto it started fine. we have used it twice since and the engine starts fine and runs at full revs for about 5 minutes then just dies to a tickover then eventually stops. i have found if i disconnect the fuel supply hose, there is no fuel in it. if i squeeze the bulb while manually operating the non return valve until i get fuel out, reconnect it starts and of it goes agin for another 5 minutes then same again. have checked all lines from tank to carb all seem ok, i am just thinking weather it may be one of the gaskets not sealed on the pump. any ideas would be greatly appreciated as most of our trips are night time.
thanks in advance"

"could be vent line, fuel line

"could be vent line, fuel line or fuel pump"

pump the ball when running. if

pump the ball when running. if it keeps running go to the fuel pump. if You have an anti siphon valve in tank. check that too.

It sounds most like an air lea

It sounds most like an air leak in the fuel line.
To exclude the pump run it with the fuel tank higher than the engine. If its only the pump fuel will feed by syphoning and notor will run. if it is an air leak dont forget the o rings on the fuel line connection to motor. Let us know how you get on.

"update to my fuel problem, we

"update to my fuel problem, we went out today to test the engine, we ran about 3 minutes and it again slowed right down, missing then stopped. the fuel line was full as was the filter. we started it again started steaming and within 30 secs. it done it again but this time i took the fuel supply pipe off and strangely enough after about 10 secs. it revved up until the carb was empty. this happened a couple of times. it seems strangely enough as though it is pumping too much petrol. is this possible ? we only made it back to the marina by connecting the supply pipe until it slowed then disconnecting it. and so forth. this is really doing my head in. any ideas before i have to take it to a specialist?"

"Sounds to me like You may hav

"Sounds to me like You may have problems more than one place, but with one common thing: Dirt!
Small pieces may have blocked the valves in the pump preventing it from working properly. They may now have moved to the carb making the float valve not seal properly and then flood the carb.
Dismantle and clean out/rebuild the carb."