225X fuse blowing???

[tozlakes]

On the side next to the Motorola ECU is a small box containing 2 10amp and 2 15amp fuses. I've blown 3 of the 15amp guys over the last few times out which does not allow the motor to start. It will still turn over but that is it. Once replaced it fires right up and runs fine. Seems like it blows when taking off out of the hole and once when I was idling and the motor bumped a sandy bottom. Vibration related maybe?
Can anyone tell me what these fuses are for. Thanks John

[WATERWINGS]

I had that happen a few times on my older 2.4's, and thought it was a loose connection causing it, but not sure.

It hasn't done it in a long time.

[David L]

This is what the 225X Shop Manual Says.

Looking at the 4 fuse block with the release snap facing at 6 o’clock or down position:


Top left: Smart Craft Data Bus Circuit: 15 amp for SN OT851950 and below. 5 amp for OT851951 and above

Bottom Left: Fuel Injectors, Fuel Pump, ECM Driver Power, Oil Pump Circuit, 20 Amp

Top Right: Main Power Relay, Ignition Key Switch, Cowl Trim Switch: 20 Amp

Bottom Right: Ignition Coil Circuit: 20 Amp

[C-Webb]

Blowing it repeatedly is not a good sign, I wouldn't think it's a coincidence..

[tozlakes]

David, Thanks for the all important feedback. After reading this I now believe that the blown fuses were actually two different blown fuses over three incidents. The first time when I dug the skag in the sand at idle the complete helm power, trim and starter was dead. (top right fuse) I replaced the 15amp fuse with a spare 15 amp fuse. Being that my serial is OT 652024 I read that it should have a 20 amp in it. Is this correct? The last two times were a different story with the power to the helm still good, the starter engaging but no fuel or ignition to start. (bottom left & bottom right) These both also have 15amp fuses.
Sounds like if I were to install the three 20 amps and the one 15 amp for the smartcraft it may put it back to normal without damaging any of the electronics. This would give me the chance to test and safely if I read your response correct. Any opinions?

[tozlakes]

March 09 update: I have a 225X that blew the 20 amp fuse 3 or 4 times over a couple week period. Got help from a few guys on S&F to determine what fuse was what. Seemed to be intermittant. Did not do it for a while then all of a sudden today I go to put the boat in the water and no power to fire the ignition. Went straight to the fuse that supplies the fuel Inj, pump, ECM, oil pump and sure enough it was blown. Last time out had no problem but after sitting for 4-5 months it not only blew the fuse but continues now to do so. Looked at all connections and they seem to be fine. Could the fuel pump be locking up? two leads to it looking like a positive and a negative, could I put 12 volts to it to turn it over to determine its condition? ECM issues to check? Oil pump? I think it is vacuum operated not electric is this the case? Any feedback appreciated.
Got some feedback on another persons thread taalking about loose grounding connections. Checked all positives and negatives yet still blowing fuses. JG

[tozlakes]

Just went through the process of elimination by disconnecting the fuel pump leads, oil pump leads and the main 12 wire plug coming from the ECU going to the injectors (all tied into this faulty fuse). I then turned on the key and the fuse held. I plugged both pumps back in and tried to turn the engine over and the fuse held. When I went to plug in the injectors the fuse instantly blew. I then went through the process again in a different order and each time I plugged in the injectors the fuse would blow. Could this be an issue with the Motorola ECU, injectors or ignition switch? What are some steps to perform at this point as to pin point the fault within the injection system? Thanks, JG

[tozlakes]

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[tozlakes]

Need any help I can find!

[tozlakes]

The issue ended up being a stripped wire within the air inlet plenum that feed each of the injectors. Strange deal but there are some 24 wires or so that run within the plenum and have a couple hold downs for the harness. Tight fit and one of the wires wore through at the point of the hold down creating an intermittent ground causing the fuses to blow. Not long after this the motor did not start again so I went directly to the fuses but found them to be good. After more distress found out that the Motorola ECU was the issue. Was told by Rapare that this is a common issue and had them make me up another ECU unit at a cost of $1200. Ouch.



Need any help I can find!