Starts but dies!!!?

[Hardsuction]

I have a 02' 20ci Tige with a 5.7 mercruiser ski engine -

When you start the engine if fires up fine but then is immediately stopped/cut out!

I have had this problem since i brought the boat and it has been intermittent until now as it won't run at all.

I have been told that it maybe a engine safety mechanism - won't let you run the engine if there is a problem. So it may be a faulty reading/sensor as all dials read fine. Someone also mentioned it could be an earthing problem?

Do these boats have an engine management system? Could a mercruiser agent plug in a diagnostic tool?

My local agent won't touch it as it runs on LPG! Anyone know of a reliable marine mechanic in the Bristol area who won't rip me off, knows his/her stuff and is not scared of gas!

Any help appreciated - the seasons short enough as it is.

[ally606]

sounds like your lanyard (dead man's switch). Make sure it is properly connected and also make sure the wires on the back of it haven't come loose or are corroded.

[Hardsuction]

ally606 - Checked that just to make sure and when the dead man switch is not in place there is no power/electrics at all.

The engine fires, but then after a split second cuts out dead. No spluttering or anything just total cut out.

Thanks though.

[rossl]

When you turn the ignition power on can you here the LPG tank solinoide click to open the valve to let the LPG to the engine?

Rossl

[Hardsuction]

Ross - yes you can hear the solenoid - fuel is getting there as it fires up fine.

Don't think its fuel as no spluttering or trying to run but doesn't.

Something kicks in and stops the engine from running!

[rossl]

If you are getting fuel, its electric, either the dead man or ignition/starter switch is shorting, these are the only 2 things that can kill a running engine. Cleaning all the connectors is where i would start, remove the deadman and put a wire in there to bypass it for testing, our switch went out on our boat even though the deadman looked good, then move onto the ignition switch. If you need a hand give me a shout and i'll bring my multimeter, should be easy to find.

Rossl