Blown Engine?

[dfaulk]

I have a 1998 Mercury 225 EFI. I just recently replaced the fuel pump and this morning I went to run the boat for the first time since the repair. The boat started fine but killed. I tried several times to re-start the engine and it would not re-start. I noticed that a dark fuel/oil mix was draining out of the lower unit where the prop is mounted. Is my engine blown?

 

[rodbolt]

Re: Blown Engine?

I doubt it. a quick compression test will tell. also test the fuel rail pressure and the spark.

 

[WillyBWright]

Re: Blown Engine?

My guess ... the fuel pump failed due to varnish and one or more injector is suffering from the same malady. Stuck open.

 

[dfaulk]

Re: Blown Engine?

The pump did fail due to varnish. Why would fuel oil mixture be leaking from the lower unit exhaust?

 

[dfaulk]

Re: Blown Engine?

The pump did fail due to varnish. Why would fuel oil mixture be leaking from the lower unit exhaust?

 

[rodbolt]

Re: Blown Engine?

if its running rich due to a stuck VST needle or a bad low pressure pulse pump diaphram or anyother reason then yep your gonna flood the motor and all kinds of black nasties will come out the exhaust. however none of it indicates a blown motor or not, just indictes unburned fuel in the exhaust

 

[dfaulk]

Re: Blown Engine?

How invloved or costly is the repair that you are describing? As you probably are already aware, the fuel pump replacement was pretty costly with the fuel pump alone costing $650. Was this something that the dealer should have checked when he replaced the fuel pump?

 

[rodbolt]

Re: Blown Engine?

the low pressure pump kit costs maybe 15 dollars or so and can be done in 30 min or so, the rest wil require a fuel rail pressure gauge and a spark tester.<br /> if you have an injector leak a fuel pressure test will find it. merc has a tester for EFI to give a pulse to each injector to test pressure drop across the rail to look for clogged injectors as well. does your dealer have the merc EFI test box ?<br />its a simple system but requires some EFI basic knowledge a service manual and some test equipment. without it your shooting blind.there are some ign failures that will cause loss of spark but not loss of injection that will cause your symptoms as well.<br /> Time to break out the diagnostic equipment.

 

[Big T Bassman]

Re: Blown Engine?

Check the float in the VST. I went through de gumming an EFI. I had to soak the electric fuel pump and finally got it free. The float stuck and gas would overflow. Take off the cowl and pump the ball. If you see gas pouring out the float is probably stuck. The last time mine was stuck I pumped the ball and raised and lowered the motor and she broke loose.

 

[mistylady]

Re: Blown Engine?

and i thought i was the only one that had problems with merc efi. i have blown 2 powerheads on a 2001 merc 200efi. from what you said i doubt you blew yours up. good luck<br /><br /> mistylady