2003 Utopia 205 - Mercury 240EFI blowing fuses

[M3Man03]

Had a problem this weekend - the boat under power would sputter and die almost like I ran out of gas. Then it would not restart again.

After checking the engine over, it appears a fuse blew on the starboard side in a block of 4 fuses.

I kept blowing a 20A fuse over and over again, primarily when it was a cold startup (not been running for a couple hours).

I'm not sure why it's blowing - any suggestions?

Here's the fuse block location:

Here's the fuse block in question:

Here's the fuse that's blowing:

 

[Dr Honda]

I'm confused......


the "K" in the diagram only has one fuse in it. The block with 4 fuses is on the Starboard side. Please post a picture, of the actual fuse that's popping.


But regardless... if you are popping the fuse for the lift pump... I'd say the pump is shorted out.

 

[M3Man03]

You're right, it's the starboard side, with the fuse holder with 4 fuses in it. I'm pretty sure if the clip is at the bottom, it's the lower right fuse that is blowing.

What is the lift pump? How can I check to see if it's shorting?

I don't have a good picture of the engine because the manual only seems to have the older 240EFI diagrams - not the newer one. My engine is slightly different than the image.

 

[M3Man03]

My engine looks like this:

But I can't seem to find a clear starboard side image.

 

[Dr Honda]

I know what the different engines look like, so I don't need generic pictures. I want a REAL picture of YOUR fuse that is popped.

I'm not trying to be harsh... but since you gave me wrong info on the first post... I don't want to be guessing about want may be wrong. Once you post it... I will be more than happy to answer your questions.

 

[M3Man03]

I will get you one in a couple hours. I understand what you mean. Please check this thread again in a bit. Thanks!

 

[M3Man03]

Dr Honda, here's the pictures you requested:

Here's the fuse block location:

Here's the fuse block in question:

Here's the fuse that's blowing:

Any help would be greatly appreciated! Even just knowing what that fuse is for, if you don't have a solution.

 

[M3Man03]

Found a manual for my engine online - says that fuse is "Ignition Coil Circuit". Why would that blow? Could that have something to do with my loss of power on the top end? I only get to about 4800rpm lately but still can get to about 40mph with 2 people in the boat.

 

[Dr Honda]

OK... great. That's exactly why I wanted the real pic. Now we know it's not the pump. Give me a few minutes to dig into the schematic on that engine... and I'll be back.

 

[Dr Honda]

OK... great. That's exactly why I wanted the real pic. Now we know it's not the pump. Give me a few minutes to dig into the schematic on that engine... and I'll be back.

 

[Dr Honda]

OK......


The coils on the newer 240 are DC... and that fuse is all the power to the coil packs.

So... either there's a short in a wire somewhere... or one of the coil packs is going bad. I would start with a good de-greasing of the engine, and then run your hands over the red/yellow wires, and look for a spot that may be chaffed.

If the wires look ok... then grab a meter and start checking the coil packs.

 

[M3Man03]

What readings should I take/get from the coil packs? Am I measuring resistance or?

 

[M3Man03]

Any suggestions on how to "test" the coil packs?

 

[Dr Honda]

On that coil pack... there's a big chart on what to expect between the pins. Do you have the manual for the info? If not... you really need it with this engine.

 

[M3Man03]

On that coil pack... there's a big chart on what to expect between the pins. Do you have the manual for the info? If not... you really need it with this engine.

What page? I found it online. Are you taking about page 2A-24 & 2A-25 in the manual?

 

[Dr Honda]

Sorry I didn't et back to you sooner on this one. I was flying back from Boston.


The chart for your engine is on page 2A-2 and on 2A-24 of the 2002 engine book. Page 2A-25 is the MAP sensor.

It will take a little time... but check each coil, for each of the combinations.