To many engine cranks to start

[Rundlewood]

2008 mercruiser 5l mpi efi takes 6 cranks every time to start weather hot or cold etc., have replaced plugs, rotor & cap but still 6 cranks to start every time. Once started engine runs smooth at every RPM, never misses a beat once started. Does seem hard on fuel but have not owned & operated long enough to be sure but compared to other boats I have owned it seems hard on fuel. Any ideas?

 

[alldodge]

What do you mean by 6 cranks?
Turn the key and the engine cranks over several times, stop and crank again, then repeat, or motor cranks over 6 revolutions before it starts

What's your serial number?

 

[wellcraft-classic210]

1 thought

It might be taking a while to build up fuel pressure // Could be a warn fuel pump --

 

[Rundlewood]

Wellcraft-classic 210 - I agree the problem is probably fuel bug if pump was worn it should show at hight rpm & it runs good at high & all other rpm. I am thinking it is a poor seal somewhere allowing pressur ed to release in the fuel system.. do you know what fuel pressure should be & how to check it?

 

[QBhoy]

Hi
Same engine (if it's an mpi)....when you turn the ignition on, can you hear the fuel pump running for a few seconds building up the pressure in the rail and then stopping ?

 

[QBhoy]

Also...if you mean 6 cranks as in revolutions of the engine....this isn't probably far off normal. I've never really been able to tell how many times it turns over before it start.
If you mean you need to crank it 6 times with the key....that's a different ball game.
Mine starts after I turn the key on...listen to fuel pump running them cutting out, then turn key....maybe 3 secs later from cold it will start.

 

[wellcraft-classic210]

Yes -- I would try to see whats going on with fuel pressure when you start it using a pressure gauge if possible. A worn pump can be slow to prime but work OK once primed.

 

[QBhoy]

Turn the key on, listen for fuel pump building up pressure and cutting out...the stick your finger nail into the test point valve on the fuel rail...make sure there are no signs of air. If there is, you may be drawing air on the LP suction side of the pump....or you have just changed fuel filter dry !....probably not though

 

[Rundlewood]

QBhoy - Thank you for your tips they sound very worth while to try. Unfortunately I had to winterize the boat so I will have to wait until spring to try them. I am much more familiar with a curburetor....Where or how can I identify the test point valve on the fuel rail as you suggested?

wellcraft-classic210 - thank you for the info on a worn fuel pump