Vapour lock

[Spaniard_King]

Hey Kev,

Vapor locks do occurr, mainly when there is a fuel leak and the bulb allows fuel to flow back to the tank, hence air will leak into the fuel system.

I would be putting as much pressure as you can on the primer bulb without rupturing a blood vessel ;D at the same time look around the engine with engine cowl off for any sort of fuel leak. Hopefully you will find something to fix.

The other thing is if the fuel bulb is not of recent time it could be worth replacing.

cheers

Garry

[QldKev]

Went out for a run yesterday; boat run excellent all day. Got home, got the hose out for a flush and no start. After 15 mins playing around; good spark etc, no fuel. Fuel bulb felt hard, took the hose off after the fuel pump and pumped the fuel bulb and only air / fuel vapour. Pumped 3 times until fuel came out, put it back together and it started straight away. How many people have heard of outboards with vapour locks? The engine is a 1977 Merc 850, has never done this prior. Also does everyone have the fuel priming bulb at the start or at the engine end of the fuel line. My other boats have always been at the start, this is at the engine end and in direct sun ??

[Hagar]

Odd one Kev

The primer bulb should pump past the fuel pump until the carby floats rise and shut off the flow when the carby's are primed . Possibly something sticking in the fuel pump ? . Garry is the man for this so hopefully he will see the post . I would get the primer bulb out of the sun if I could if only to stop it perishing .

Chris

[QldKev]

Thanks for the replies; #will have a look this weekend for any fuel leaks. #I did notice where we took the fuel hose off after the pump there was no clamp on it; maybe this is the cause. #Also Probably a good time to look at replacing the fuel hose. #Not to sure how old it is, so could be good insurance to throw this on in the spares box.

[youngfisho]

I had the same problem you described with my motor having stalled after a run out to the fishing grounds, putting it into gear after having stopped for an hour and the motor would conk out. I would check the bulb and hey presto no fuel. I changed all of the fittings used SWAN 8mm fuel hose and made sure all fittings were new. Solved the problem. I still give the bulb a squeeze though if I have been fishing in the one spot for a while to ensure the fuel is up to the motor on starting.


andrew

ps: the problem always seemed worse when the motor had been run for a little while (more air able to enter the fuel line whilst running for longer periods and also because the auto choke function doesnt kick in when the motor is warmed therefore slower idle speed and decreased fuel pressure)

[Gone_fishin]

Hi

First I would make sure that you have no leaks or blockages
It genarally happens when you have a leak and with the heat it will become an air lock