Resealing ECU Black Box

[svana]

Well, a day on the water got scrapped today due to (I believe/hope) a starter solenoid crapping out. I’ve cracked open the black box behind the motors to get to it, breaking a few seals of RTV. Should I try and clean all the old stuff off and reseal wherever I’m seeing remnants of it? Doesn’t particularly clean off easily and I don’t want to tear the rubber gaskets.

 

[Beachbummer]

What boat? No RTV on mine only a gasket. Pictures?

 

[svana]

What boat? No RTV on mine only a gasket. Pictures?

08 SX230HO.

 

[Beachbummer]

I agree with your assessment. Worst case add a little rtv if you think it needs it. The gasket should be plenty to seal it. I've sealed it dry and re examined after 24 months and it was dry as a bone

 

[Bruce]

I would focus on making sure the top edges have a good seal.

The 2006 and older MR-1s are known for water intrusion causing injector(s) to stick open. Not sure if Yamaha knew that before 2008 but it might have motivated the addition of the RTV.

 

[svana]

I would focus on making sure the top edges have a good seal.

The 2006 and older MR-1s are known for water intrusion causing injector(s) to stick open. Not sure if Yamaha knew that before 2008 but it might have motivated the addition of the RTV.

What are you referring to by top edges? Figured the bottom would be more susceptible to water intrusion although drainage would be positive as well - maybe not on a sealed unit though lol. FWIW it’s bone dry on the inside.

 

[Bruce]

@svana, I certainly am no expert on this but I would think that water would be most likely to intrude by splashing or raining in through the rear seal of the engine hatch then dripping down onto the control box. I would not expect it to rise up from below.

 

[svana]

@svana, I certainly am no expert on this but I would think that water would be most likely to intrude by splashing or raining in through the rear seal of the engine hatch then dripping down onto the control box. I would not expect it to rise up from below.

This is true, I hadn’t considered that.

 

[Beachbummer]

You need to be overly careful on this year model, as Bruce says, water seeps in from the top rear of the hatch, and then remains inside the "sealed" box, ruining the ECU. If It was me I would also apply a single strip of duct tape starting on the bottom vertical corner at either side, to the seam at the top and all the way to the other vertical line, leaving only the bottom seam without tape. This might be total overkill and unneeded, but if you search for wet ECUs on the board you might see some pictures of what Bruce is referring too.

Best of Luck! Did you confirm it was the relay? Hopefully ready to go out soon!

 

[svana]

You need to be overly careful on this year model, as Bruce says, water seeps in from the top rear of the hatch, and then remains inside the "sealed" box, ruining the ECU. If It was me I would also apply a single strip of duct tape starting on the bottom vertical corner at either side, to the seam at the top and all the way to the other vertical line, leaving only the bottom seam without tape. This might be total overkill and unneeded, but if you search for wet ECUs on the board you might see some pictures of what Bruce is referring too.

Best of Luck! Did you confirm it was the relay? Hopefully ready to go out soon!

Not confirmed but when I jumped the two terminals/cables it cranked, so I’m hoping that’s the case. New part comes tomorrow but not sure when I’ll get to it. Got a fence knocked over and lower control arms on the truck that need new bushings that are pulling me in all sorts of directions.

 

[Beachbummer]

If you jumped it and it engaged, 99.9% it's the solenoid. The window let's you jump it in an emergency and still get it started. If you ever need it. (If you were very desperate to go out, for example . )

 

[svana]

If you jumped it and it engaged, 99.9% it's the solenoid. The window let's you jump it in an emergency and still get it started. If you ever need it. (If you were very desperate to go out, for example . )

Ya…I came across that video after I had taken the engine bay apart lol.

 

[svana]

Well…I’ve now swapped 2 starter solenoids (first one was seemingly DOA so I went and bought an OEM one). The second one briefly started cranking but was still blowing my 20a starter fuse every time. Any ideas on what else to chase down? Nothing seems obviously burnt out or out of place.

 

[Bruce]

Is the starter the issue?

Anything stuck in the jet pump making it more difficult to spin the motor?

Does it really only take 20 amps to spin our starters?

 

[svana]

Is the starter the issue?

Anything stuck in the jet pump making it more difficult to spin the motor?

Does it really only take 20 amps to spin our starters?

I’m not sure on the first 2 questions, but ya they’re a 20a fuse (you can see it noted on the first photo in my post above)

As for finding the issue, I’m going to do my best to trace where the grounds and other connections are (kind of in the dark there) and check the pump as well. If neither of those are successful, I guess I’ll have to look at replacing the starter.

 

[Beachbummer]

I think the starter draws way more than 20 amps and it's not fused. That fuse might be for something else, not just the starter for sure.

 

[svana]

I think the starter draws way more than 20 amps and it's not fused. That fuse might be for something else, not just the starter for sure.

Maybe, but it’s definitely wired to the solenoid at least. And whatever it is it’s tripping it lol

 

[svana]

Additional data point from this morning: I turned the key switch to ON only (didn’t try and crank) and the 20a fuse popped again. This leads me to believe it might not be the starter since it wasn’t even engaged?

My next thought would lead me to believe it’s some type of short somewhere, no? I’ve so far checked the connections on the main lugs positive and negative (the only ground I could find sits low on the stbd side of the engine and goes straight to the batt terminal). Any other places to immediately check? I’m gonna keep disconnecting till it doesn’t pop I suppose. Might need more 20a fuses lol

Edit: Upon working on further isolation, disconnecting the main harness eliminates the short. I guess theoretically that means it’s one of the 7 wires connected to it? Could also be a short from the dash from when I replaced the switches, but that doesn’t seem correlated at first thought.

 

[Brad_Ct]

Maybe, but it’s definitely wired to the solenoid at least. And whatever it is it’s tripping it lol

The fuse wire is connected to the same lug on the starter relay as the positive cable from the battery not the starter side.

 

[svana]

Well, much to the surprise of absolutely no one, the short was caused through 100% my fault, when replacing all of the switches on the dash, there were 2 ends of a perfectly matched barrel connector that even had the proper matching heat shrink that naturally must have been disconnected at some point! Nope...So of course you just smile and laugh at the fact that the whole back of the boat was torn apart for my own stupid reason...

On the subject of the thread, I ran a bead of liquid electrical tape along the top of the ECU box to help further keep any water that may fall on it, I think it's the best option for the situation. Of course I forgot to take a picture though, but this is the stuff.