Mercruiser MPI Won't Start

[r2d2a]

I don't have the model number but have I think enough info about the engine for what is going on. It is a 2002 MPI v-8 Bravo with an ECM 555. I let it sit for a few weeks and when I came back it wouldn't start. It will crank and crank and when I let go of the ignition switch it almost sounds like it has a little kick at the end but not close enough to start. I've done a few things so far:
Batteries are good, I checked spark which is good on all cylinders, replaced cap and rotor anyway, checked fuel filters for water but there was none, checked fuel pressure at the schrader valve which was fine. Not sure what test I should do next, plus I thought I would check to see if anyone has had this happen to them, thanks.

 

[Bondo]

Re: Mercruiser MPI Won't Start

It will crank and crank

Ayuh,.. Is the injector spraying at that time,..??

 

[Fun Times]

Re: Mercruiser MPI Won't Start

It will crank and crank and when I let go of the ignition switch it almost sounds like it has a little kick at the end but not close enough to start. thanks.

Sounds like you may have a bad ignition key switch.

Does the dash power up like normal?

Double check your safety ignition kill switch.

 

[r2d2a]

Re: Mercruiser MPI Won't Start

I didn't check anything with the injectors, I did try to feel them as I was cranking and I did feel clicks. I felt most of them but not all. There is fuel in the water though like it is going into the cylinders and out the exhaust but not being burned, if that helps. As far as the switch, I'll disconnect the harness tomorrow and see if I can get it to run just at the engine side and not the boat side. I do have a computer I can hook up so maybe I'll try that and see if it tells me anything about the injectors.

 

[r2d2a]

Re: Mercruiser MPI Won't Start

I got it. A little over a month ago I put in 8 new plugs, used it a couple of times and haven't touched it for a few weeks. Two out of the eight plugs were bad. I pulled each one and tested each one with a meter, two of them had continuity from the tip of the plug to the thread when it should only have continuity from the tip to the spark gap section (don't know the name). I guess this is why I was able to have spark too since it was still grounding at the threads. I find it a little odd that this happened to brand new and expensive plugs but I guess anything is possible. After I switched the plugs it started right up.
Thanks for the help.

 

[ChrisCraftJohnny]

Re: Mercruiser MPI Won't Start

Define: "New and expensive plugs"

The PO of my craft had BOSH 4 electrodes in the engine. Very expensive. Very fancy. And Very wrong. Engine ran like crap on them.

I changed them with the correct NGK's that are listed in the Merc. manual and presto-chango, perfection! To me, all those nonsence multi electrode spaahk-plugs are gimicks!

CCJohnny

 

[r2d2a]

Re: Mercruiser MPI Won't Start

It sounds like they weren't nearly as expensive as yours so I shouldn't complain, just glad it is all fixed.

 

[Fun Times]

Re: Mercruiser MPI Won't Start

Thanks for the update.

Kind of curious, What brand name & part number plugs did you install?

 

[r2d2a]

Re: Mercruiser MPI Won't Start

The plugs were AC Delco 41-993. This is the newer number, they were another number until pretty recently.

 

[Fun Times]

Re: Mercruiser MPI Won't Start

The plugs were AC Delco 41-993. This is the newer number, they were another number until pretty recently.

Did you re adjust the gap while checking the gap? Or did you leave them pre gapped from new?

 

[r2d2a]

Re: Mercruiser MPI Won't Start

The gap came just under the spec of .060. I still did it but the difference was so small I don't think it would have mattered if I left it alone.

 

[Fun Times]

Re: Mercruiser MPI Won't Start

The gap came just under the spec of .060. I still did it but the difference was so small I don't think it would have mattered if I left it alone.

You might want to read this older thread about about Re gapping those style plugs, It's not recommended to re gap them, just carefully check them to see if they are still within a reasonable amount of range from new.

Re Gapping them could lead to a damaged spark plug.

http://forums.iboats.com/showthread.php?t=386927

 

[r2d2a]

Re: Mercruiser MPI Won't Start

Haha, good to know. Thanks for that post, I think they were in a reasonable spot so I guess I should have just left them. : )