Electrical Issues - Help?

[BioChemLab]

Hey guys,
So after my engine swap and break-in, the boat is running great, apart from some strange electrical issues.

Every now and then (usually when the bilge blower is on...) some of the gauges will max out and stick there - sometimes toggling the bilge blower on/off will fix it, sometimes it won't. While checking for good grounds today, I noticed that with the bilge blower on (and the engine off, not in the water, etc) the note of the blower changes every now and then. It seems to be getting an intermittent bad ground - or something along those lines, and I'm not sure what to do next.

I've verified good low impedance ground on all of the connections on the back side of the helm plate, and I've unplugged and replugged every connector I can find, checking for corrosion and such, and found nothing. I've also unplugged all the other aftermarket stuff I've added (light bar, aftermarket stereo, amp etc) to make sure none of that is causing an issue. So far, nothing has changed.

I did notice when I was putting the engine back together that I guess at some point I smacked the oil pressure sensor (the three-wire one down by the oil filter), it looks like just the plastic that cracked but messing with that plug seems to sometimes rectify the problem, but I can't be sure if that's coincidence or has something to do with it. I can't imagine that the ground for the entire switch panel/helm runs through the oil pressure switch - right...?

Thanks.
Jon

 

[BioChemLab]

I guess I misspoke - the oil pressure sensor I was talking about is a two wire unit, not three wires.

I've been out there going through it all again trying to get the boat ready for the fourth, but I've found no change. I did notice that the ground spot on the fuse box under the driver's side kick panel had a very high resistance to ground, so I added a jumper wire to that connector pad straight to the battery, and although it sparked a little bit when I hooked it up (which speaks of a bad ground wire in the harness, no..?) it didn't seem to help.

When you turn on the blower, the oil pressure gauge moves a little bit. I'm not sure if that helps a diagnosis or not, but it looks like the main gauges that have issues are the oil pressure, water temp and fuel gauges.

 

[dingbat]

A change in blower speed would suggest a voltage drop.

Put a meter on the supply to the fan to look for a voltage drop. If you don’t find a voltage drop, I’d be looking at the blower motor for worn brushes, bearings hanging up.

Would affect everything wired that circuit.

If nothing else, unplug the oil sensor and see if everything clears up

What do you consider a “low impedance” ground?

Ideally should be as close to zero as possible.

 

[BioChemLab]

A change in blower speed would suggest a voltage drop.

Put a meter on the supply to the fan to look for a voltage drop. If you don’t find a voltage drop, I’d be looking at the blower motor for worn brushes, bearings hanging up.

Would affect everything wired that circuit.

If nothing else, unplug the oil sensor and see if everything clears up

What do you consider a “low impedance” ground?

Ideally should be as close to zero as possible.

Thanks for the reply! All the grounds behind the dash were less than an ohm to the ground post on the battery - .2 and .3 mostly.

I hadn't thought of the blower itself being bad, I really wish I still had my power probe to measure current draw to the blower while it's running. I did test battery voltage (at the dash) while running the blower, and it dropped to 10.6ish from 12.6 when I turned it on. The battery is a brand new optima blue top with a fresh charge, as I was cranking for a while before I got the new engine started the first time. My battery charger says 98% charge on the battery.

However, after running the blower on and off and testing and unplugging stuff and etc etc, now the blower doesn't work at all. It makes a lot of sense that the blower was packing up, drawing a whole bunch of power and overwhelming the gauges on the same power circuit. It also explains the intermittent nature of the fault - I would assume.

I'm gonna get the dash cleaned up and reinstalled, connect everything back together then try it again. If the blower is still buggered, I'll replace and report back.

I appreciate your thoughts!
Jon

 

[achris]

This is what happens when you hang all your accessories off the engine circuit. Accessory decides to act up and it affects the engine.You really need to get items that are not part of the engine, off the engine electrical system.

This is how my boat is set up and I rarely have electrical issues, and when I do, the accessories don't 'contaminate' the engine.

 

[BioChemLab]

This is what happens when you hang all your accessories off the engine circuit. Accessory decides to act up and it affects the engine.You really need to get items that are not part of the engine, off the engine electrical system.

This is how my boat is set up and I rarely have electrical issues, and when I do, the accessories don't 'contaminate' the engine.
View attachment 344448

Man that's funny - I actually think I saw you reply to someone else who had asked a gauges question on another forum (or maybe just a different board on this one). I thought... HM, that's a damn good idea. I need to just re-wire the entire boat minus the engine on its' own circuit, that way I know all the connections are done right, and also that you don't get this stupid horseshit about a blower motor making your gauges read wrong.

I am constantly blown away by just how janky the factory wiring is on this entire vessel. The engine wiring is better, but I honestly think they just have orangutans at the Sea Ray factory. Most of the butt connectors aren't even heat shrunk, just those shitty plastic "insulators".

This picture is FACTORY wiring. This boat hadn't even had an oil change done in at least five years when I got it, so I know for a fact that the dash wiring has never been touched. This buzzer was butt connected to the power post on the back of the tach, and then grounded through a daisy chain to the same ground that runs the depth finder. Absolutely asinine.

 

[achris]

Man that's funny - I actually think I saw you reply to someone else who had asked a gauges question on another forum (or maybe just a different board on this one). I thought... HM, that's a damn good idea. I need to just re-wire the entire boat minus the engine on its' own circuit, that way I know all the connections are done right, and also that you don't get this stupid horseshit about a blower motor making your gauges read wrong.

I am constantly blown away by just how janky the factory wiring is on this entire vessel. The engine wiring is better, but I honestly think they just have orangutans at the Sea Ray factory. Most of the butt connectors aren't even heat shrunk, just those shitty plastic "insulators".

This picture is FACTORY wiring. This boat hadn't even had an oil change done in at least five years when I got it, so I know for a fact that the dash wiring has never been touched. This buzzer was butt connected to the power post on the back of the tach, and then grounded through a daisy chain to the same ground that runs the depth finder. Absolutely asinine.
View attachment 344449

Yeah, that's pretty crappy. My boat wasn't much better when I got it... Now the back of my dash looks like this....



I've also replaced the poxxy glass fuse Merc supply for a mini-blade fuse and holder (highlighted). Never going to suffer from the common problem of corrosion on the ends of the fuse, like a lot of people have.

Can't see it here, but I have also added diodes across all the solenoids (starter and 2 trim) to stop contacts burning. MadProps did a great post about that nasty little issue!

This thread -> Solenoids 'hack'

Chris........

 

[BioChemLab]

Yeah, that's pretty crappy. My boat wasn't much better when I got it... Now the back of my dash looks like this....

View attachment 344451

I've also replaced the poxxy glass fuse Merc supply for a mini-blade fuse and holder (highlighted). Never going to suffer from the common problem of corrosion on the ends of the fuse, like a lot of people have.

Can't see it here, but I have also added diodes across all the solenoids (starter and 2 trim) to stop contacts burning. MadProps did a great post about that nasty little issue!

This thread -> Solenoids 'hack'

Chris........

Nice! Mine has mini-blade fuses in it from factory, but the box is a bit cheap and flimsy and I'll probably pull it out and replace it with the re-wire. Since you seem to have a fairly strong grasp of the electronics on these boats...

The previous engine did quite a bit of dieseling when it was turned off. I always just assumed it was ten years of build up and leaking fuel and probably ethanol-induced rot, and didn't think much about it. On the first trip out the new engine didn't do it once, but on the second and third trips (when I was working the engine a bit harder..) it does diesel for approximately 10 seconds after switching the engine off.

The carb is brand new, was jetted properly for the engine/intake manifold I am using, and all the fuel in the boat now is ethanol free. Some documentation on the MSD box I'm using says I can add a diode to the power in wire for the box which should solve any dieseling issues, but I figured I'd ask here before futzing with it. I've also seen that people are putting diodes in the field exciter circuit on the alternator, but I'm not sure which one would actually work. Any ideas? I'm fairly convinced it's not fuel leaking from the carb - it's brand new and marine rated.

Thanks!

 

[achris]

Doesn't matter what you do to the electricals, you're not going to stop the dieseling. Dieseling is a mechanical/fuel issue. Once you turn that key OFF, there are no sparks!

You didn't list what your engine is, but there are a few things that will be common to all engines.
1. idle speed too high (leaves the throttle open too far and enough fuel is getting in to spontaneously combust).
2. engine very hot on shutdown (allowing the engine to cool before shutting off after a hard run often stops dieseling.)
3. carbon build up on piston crowns glowing (See #2)

Chris...........

 

[BioChemLab]

Doesn't matter what you do to the electricals, you're not going to stop the dieseling. Dieseling is a mechanical/fuel issue. Once you turn that key OFF, there are no sparks!

You didn't list what your engine is, but there are a few things that will be common to all engines.
1. idle speed too high (leaves the throttle open too far and enough fuel is getting in to spontaneously combust).
2. engine very hot on shutdown (allowing the engine to cool before shutting off after a hard run often stops dieseling.)
3. carbon build up on piston crowns glowing (See #2)

Chris...........

You know, after typing all that out and thinking for a bit, I realized that the fucking great whacking carb on the top wipes out any electrical possibilities for diseling. I was typing my edit to my post when you replied - I feel dumb! I'm a long time mechanic but this is absolutely the first carb'd engine (and my first American designed engine) so please excuse my profound ignorance.

I also realized I haven't adjusted my throttle cable since I built the bracket for the new carb/throttle linkage, so it's probably something in there. Or I've got the idle set too high - I haven't played with the carb at all yet because I can't find anyone local to go to the lake with me and teach me how to tune it. I've learned a lot from YouTube, but I've found there is a lot of lost knowledge that only the old greybeards mutter to themselves. I've yet to find my greybeard vein.

Thanks for all your help. I've got the wiring behind the dash panel cleaned up and ready to go back in in the morning - hopefully the new blower will solve my issue.

 

[achris]

...I am constantly blown away by just how janky the factory wiring is on this entire vessel. The engine wiring is better, but I honestly think they just have orangutans at the Sea Ray factory. ...

Don't get 'boat wiring' confused with 'engine wiring'. The engine wiring is done by the engine supplier (in your case, Mercury) and the boat wiring is done by whoever is fitting out the boat. Might be factory, might be a dealer or reseller. But almost never is engine wiring done by a boat builder. All the wiring is done in the Mercruiser factory and the dealer/builder just drop that engine is, run the instrument harness up the side of the boat and plug the instrument panel into the harness. Where it gets messy is when the guy doing the fit out just pulls power off the back to the instrument panel, because it's quicker and (sl)easier than running a proper independent system.

Chris.....

 

[achris]

...I feel dumb!

Don't.

I'm a long time mechanic but this is absolutely the first carb'd engine (and my first American designed engine) so please excuse my profound ignorance.

There aren't many people left who properly understand carbs, but here's a video that will help you understand them...
See-thru carb

Chris.....
(Grey-beard)

 

[BioChemLab]

Don't.

There aren't many people left who properly understand carbs, but here's a video that will help you understand them...
See-thru carb

Chris.....
(Grey-beard)

That's funny. I watched that video last night. Definitely helped with some things I didn't know, but I really wish he had just filmed that 40 minutes of his dad just talking him through it!

I knew the engines and boats were built in different places, but I didn't know it then went to a separate "fitter" - I assumed sea ray bought the engines and harnesses, built the boat then put it together. Weird theyd involve more people. I get that the dealers may install like satellite radio or aftermarket sound system or whatever, but no boat is being sent out regardless of spec without alarms. Idk why they'd leave critical stuff like that to people who do jobs like this. I mean I guess it isn't really a safety issue but still.. it certainly will make me think twice about just buying another sea ray in the future.

 

[achris]

... but I really wish he had just filmed that 40 minutes of his dad just talking him through it!

He did...

 

[BioChemLab]

He did...

That's awesome! I didn't even think to search for it, I was just disappointed while I was watching it. Thanks again!

 

[nola mike]

Yeah, that's pretty crappy. My boat wasn't much better when I got it... Now the back of my dash looks like this....

View attachment 344451

I've also replaced the poxxy glass fuse Merc supply for a mini-blade fuse and holder (highlighted). Never going to suffer from the common problem of corrosion on the ends of the fuse, like a lot of people have.

Can't see it here, but I have also added diodes across all the solenoids (starter and 2 trim) to stop contacts burning. MadProps did a great post about that nasty little issue!

This thread -> Solenoids 'hack'

Chris........

You did that diode mod? I remember that thread, so cool

 

[achris]

You did that diode mod? I remember that thread, so cool

Yes, both trim solenoids and the starter solenoid. Look at the thread (link a few posts back in this thread), I posted pictures.

I have also added a 15A (double throw momentary) switch to the pump (mounted on the bracket) that powers the pump motor directly (no solenoids), so if a solenoid does crap out, I can raise or lower the drive by just reaching in and flicking the switch.

Chris.

 

[nola mike]

I have also added a 15A (double throw momentary) switch to the pump (mounted on the bracket) that powers the pump motor directly (no solenoids), so if a solenoid does crap out, I can raise or lower the drive by just reaching in and flicking the switch.

Chris.

I have a large screwdriver that serves that purpose on all solenoids and it's versatile enough to work on oil pressure switch as well. I have been thinking about throwing a relay somewhere on my ignition circuit. Rewiring the helm isn't going to happen, but there's so much potential for voltage drop. Your wiring still has power coming all the way through the ignition switch before returning to the engine harness, right?

 

[achris]

... Your wiring still has power coming all the way through the ignition switch before returning to the engine harness, right?

Yes, but being an MPI engine, it's already has relay switching for engine power.

Chris.

 

[BioChemLab]

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