mercruiser 454 MPI starting problem

[msramsey]

1999 454 MPI with Bravo III. First time out this year. Normal winterization service at end of last season. Motor will turn over, sounds fine, but won't start. Checked everything I can think of; kill switch in run and enough, new gas. Never had a problem like this before at beginning of season. Came close to catching once early, but then nothing close after. Seems like no gas or kill is on. Fuel filter? Fuel pump? Any other thoughts that I can check/change myself before waiting weeks for a service visit?

 

[Bob_VT]

Re: mercruiser 454 MPI starting problem

Welcome to iboats!!

Take a look in the ADULTS ONLY section and there are mercruiser manuals available online to diagnos problems. http://forums.iboats.com/showthread.php?t=288430

 

[Fun Times]

Re: mercruiser 454 MPI starting problem

1999 454 MPI with Bravo III. First time out this year. Normal winterization service at end of last season. Motor will turn over, sounds fine, but won't start. Checked everything I can think of; kill switch in run and enough, new gas. Never had a problem like this before at beginning of season. Came close to catching once early, but then nothing close after. Seems like no gas or kill is on. Fuel filter? Fuel pump? Any other thoughts that I can check/change myself before waiting weeks for a service visit?

First pull the fuel filter off and see if there is any gas in there, It really should be full, And if it dose poor it in to a clean coffy can or something see thur and see if you see any thing in the fuel like water or dirt then poor new gas in the filter "new or old" right now it don't matter to much for a quick test right now, but do change it out real soon, put the filter back on and try turning the key switch on and off 3-4 times and wait 5 seconds between key ups then try to start it and see what happens. You may need a fuel PSI gauge to install on the fuel rail to see what it will read, Also if you have a timing light hook it up to the coil wire and crank it over and watch the light at crank to see if it lights up at a fast pace if yes then move it to a few plug wires and see if you get some flashes. I think you will see a flash because you said it tryed one time to start telling me you have some spark right now but you are better off knowing you have a lot of spark. [FYI] If you move the throttle handel to 75% open it will tell the ecm to stop fireing the injectors while cranking, Do that if you think for some reason it is flooding out.This is just a starting point for you Good luck.

 

[msramsey]

Re: mercruiser 454 MPI starting problem

Thanks for replying. Well seems to be a fuel or fuel system problem. Pulled fuel filter (was full) emptied and put in clean gas. Gas that was pored out was very brown, almost like coke. Could this be the stabilizer? Any way, that did not help. Against my better judgment shot starter fluid in the intake and the engine would catch, then quit as soon as the fluid was gone. Did this probably too many times, but to no avail. Fuel pump comes on for several seconds when ignition is keyed on. Now wondering if gas is bad (20 gallons of new mixed with 1/8 tank of old) or there is no fuel system pressure as you suggested, but I don't have the tools to measure it. Now beyond my capability so to the mechanic we go. No boating this hot memorial weekend. I think I'll have a beer and take a nap.

 

[Don S]

Re: mercruiser 454 MPI starting problem

NEVER, NEVER, EVER, Reuse a fuel filter after you dump it out. Always put on a new one. You will contaminate the filtered side with dirty residue.
Are you sure it's fuel and not brown nasty water with a thin layer of gas on top?
When you turn the ignition switch on, do you hear the electric fuel pump run for 2 seconds?

 

[BAYLINER185]

Re: mercruiser 454 MPI starting problem

I think you can dump out your fuel filter and put it back on empty and if you turn your key a few times to run the fuel pump to fill the filter then remove the filter to see if its full again that will be a quick easy way to tell if the fuel pump is working. It dees sound like a fuel delivery problem.

As for mixing that much new gas with old gas id say your good, I doubt that its bad gas. You say the gas is brown like coke...Normally gas is pretty clear even with staybil in it I doubt it would look like coke.

 

[msramsey]

Re: mercruiser 454 MPI starting problem

Fuel pressure is 24 psi vs. minimum required of 43 psi. running pump backwards didn't help. checking anti-siphon value on tank and if that is good its on to a new pump. apparently this pump is no longer available separately, only as a very expensive kit.

Is it common for these electric fuel pumps to fail? in the spring after storage?

 

[msramsey]

Re: mercruiser 454 MPI starting problem

I almost forgot, the gas was definitely brownish throughout. there is no water or otherwise in it.

 

[fisherman73]

Re: mercruiser 454 MPI starting problem

My guess is that the plugs are fouled. you initial shot of fuel that may have been largly stabilizer or if you had used an engine fogger, may have fouled the plugs. That would be why it will light on starting fluid and it may have tried to fire once or twice initially before the plugs became too fouled to fire. I would pull them out and heat them up with a propane torch or put your spares in and give it another try. Another note is that if your fuel is contaminated it will just refoul instead of firing.

 

[Fun Times]

Re: mercruiser 454 MPI starting problem

Fuel pressure is 24 psi vs. minimum required of 43 psi. running pump backwards didn't help. checking anti-siphon value on tank and if that is good its on to a new pump. apparently this pump is no longer available separately, only as a very expensive kit.

Is it common for these electric fuel pumps to fail? in the spring after storage?

If your fuel is brown and old with any type of varinsh like you said it lookes like and has then yes your fuel pump will go bad in no time at all. And yes the anti-siphon valve will get cloged up also and need to be looked at. And look at the spark plugs to be safe, And also change that fuel filter now.:redface: