350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

[dolemite_1]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

I will definitely try that tmrw.

I'm not sure but for some reason I think the black wire went to the halon light in the dash.

The l&m jumper line = cranked engine i was talking about it is in section 6 the last 2 lines. Maybe I read it wrong

Brian

 

[Don S]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

I will definitely try that tmrw.

I'm not sure but for some reason I think the black wire went to the halon light in the dash.

The l&m jumper line = cranked engine i was talking about it is in section 6 the last 2 lines. Maybe I read it wrong

Brian

Nope, you didn't read it wrong, it says that. Going to delete it and fix it. If you already downloaded it, delete it. I will post the new corrected version soon.

EDIT: Fixed the troubleshooting file. Here is the new version.

View attachment Troubleshooting a mercruiser Starting system rev1.pdf

 

[dolemite_1]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

So I had my brother go to boat and he said when he jumped j and m that it did crank.
Question in steps 6 and 10 when you state turn the ignition to start and run, you mean the same thing right? I have been turning the key to get power but not so far as to try and crank the engine.
With that being said he also tried the second to last step in section 10 to see if there was power with the ignition turned to give it power while touching the m terminal with the test lead. He said there was no power on either engine when he did this. She he have been trying to crank the engine?

 

[Don S]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

when you state turn the ignition to start and run, you mean the same thing right?

NO! Not the same. Your ignition switch should have 3 positions. Off, Run, Start.
Start is where the starter is engaged and turning the engine over. When you let off the key, it returns to the run position automatically. You have to turn the key manually to off.

Some switches may have an accessory position where you turn the switch CCW from off. That position should never have anything on it.

 

[dolemite_1]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

Ok so I went back and retested everything with the correct usage of the start and run directions. Still no luck. The engine does crank when jumping J and M but there is no power on M when the ignition is turned to start position.

I also rechecked the ignition switch. The one thing that stands out is the I terminal only having 2 volts when ignition turned to run on the bad engine but 12 volts on the good engine.

Additionally, when I had the test lead hooked up to the positive on the battery to check the negative bus under the dash I found something interesting. Everything tested out fine with the negative bus but not really with the switch. With the ignition turned to run on the bad swicth the test lead showed 12v at the I,B and S terminals. at the I and B terminalsHowever on the good switch it showed 0.13v at the I and B terminals and 12v at the S terminal. I don't know if these means anything but thougth I would add it in.

I have not been able to jump the neutral safety swicth terminals as i can't seem to find it. I know what it looks like and am pretty sure it is on the transmission but if anyone can point me in its exact location I would greatly appreciate it.

Thx

Brian

 

[Bt Doctur]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

thinking there velvet drives the neutral switch should be right on top of the housing and will have 2 yellow wires or 2 yellow/red stripe wires.

 

[Don S]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

Your neutral safety switch should be inside the throttle/shift control.

Additionally, when I had the test lead hooked up to the positive on the battery to check the negative bus under the dash I found something interesting. Everything tested out fine with the negative bus but not really with the switch. With the ignition turned to run on the bad swicth the test lead showed 12v at the I,B and S terminals. at the I and B terminals However on the good switch it showed 0.13v at the I and B terminals and 12v at the S terminal. I don't know if these means anything but thougth I would add it in.

Something is seriously wrong if you show voltage on those terminals with the test light wire attached to the positive battery cable.

Do tests 8-9-10-11 and post your results.

 

[Bt Doctur]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

350 Mag Horizons .Never mentioned drive or transmissions.Could he have inboards?

 

[dolemite_1]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

So I won't be able to get to the boat today but will check tmrw. I will check steps 8-11 again. Just to verify that I am doing step 8 correct; I am attaching my long lead directly to the batteries positive terminal and the positive side of my multi meeter. Then using the ground lead on my multi meter as the test lead on the negative bus bar terminal looking for a good ground; correct?

Also would using one of the wires of the good switch hooked up to the bad switch help narrow things down?

Lastly the drives are bravo 3's

 

[Don S]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

350 Mag Horizons .Never mentioned drive or transmissions.Could he have inboards?

His engine serial number shows it's a sterndrive engine, not MIE.

EDIT: Started typing then stopped to watch the race.

 

[Don S]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

I will check steps 8-11 again. Just to verify that I am doing step 8 correct; I am attaching my long lead directly to the batteries positive terminal and the positive side of my multi meeter.

Start with item 7 instead of 8 and don't go blindly moving wires around unless you know what you are doing and why.

 

[dolemite_1]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

Here are the results.

I cleaned all the terminals on the ground and positive bus bar. With my long lead connected to the battery I tested the ground bus bar and got 11.22 v with batteries turned off and 12.66 with batteries turned on.

Next the ignition switch was tested with my long lead now connected to the ground bus bar per the instructions

B- 12.66v
I- 2.23v while in run position (pretty sure should be 12v)
S- .14v. While in the start position

Also when I test the M terminal in step 12 it shows .16v while the ignition is in the start position


What do you guys think.

 

[Don S]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

Here are the results.

I cleaned all the terminals on the ground and positive bus bar. With my long lead connected to the battery I tested the ground bus bar and got 11.22 v with batteries turned off and 12.66 with batteries turned on.

Next the ignition switch was tested with my long lead now connected to the ground bus bar per the instructions

B- 12.66v
I- 2.23v while in run position (pretty sure should be 12v)
S- .14v. While in the start position


What do you guys think.

Assuming you had the long test lead hooked to the positive battery terminal (You just said battery, and there are 2 choices), you are showing a volt and a half drop when there should have been none.
You need to start checking ground cables and missing ground wires at the batteries.
Also make sure all your cables are shiny clean and tight (with a wrench), and that the cables are good.
With those numbers on the ignition switch I would say you had a bad switch, but since you swapped them at one point, that's probably not it.
Something is either wired wrong, missing, or a poor connection.

 

[dolemite_1]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

Yes, I had the long lead hooked up to the positive terminal on the battery. Concernin the 1 1/2 v drop in the ground, what would allow the other engine to start? Also why does the voltage go up to 12.66v when I have the battery turned on to check it?

I have cleaned all the battery terminals and grounds coming off of them but will start following up on the other areas.

Lastly I took apart my gear shift looking for the neutral safety switch. Is this it in the pic? It has 2 yellow / red wires going to it. I didn't want to jump them yesterday to test it out in case it wasn't.

 

[Fun Times]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

View attachment 190508Lastly I took apart my gear shift looking for the neutral safety switch. Is this it in the pic? It has 2 yellow / red wires going to it. I didn't want to jump them yesterday to test it out in case it wasn't.

Yes, the two yellow/red wires are for the neutral safety switch in your picture.

 

[Don S]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

Yes, I had the long lead hooked up to the positive terminal on the battery. Concernin the 1 1/2 v drop in the ground, what would allow the other engine to start? Also why does the voltage go up to 12.66v when I have the battery turned on to check it?

I don't have a clue why, but it's time to find out.
Here is where we go first.

Take one battery, make sure it's fully charged. Hook it directly to the to the engine, no battery switch or anything. Hook a red cable from the starter to the + terminal of the battery, and a black cable from the ground terminal on the engine hooked to the - battery terminal.
Nothing else on that battery. See if it will crank over.

 

[dolemite_1]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

So I started to clean more terminals today to no avail. I also jumped what I presume is the neutral safety switch in the above picture with an allen key but nothing at the ignition. I couldn't test the M terminal on the slave solenoid per the attachment while it was jumped since I had no helper.

Finally I still couldn't get past the 2.23 v on the I terminal of the switch (purple only wire). So I jumped a wire from the I terminal of the good switch to the I terminal of the bad switch and the engine cranked when I turned it to start. however there was no fuel pump priming noise or buzz when the key was in the run position. I have no clue what this tells me if anything.

Where does the I terminal (purple wire) go? Can I run a wire directly to were it needs to go from the ignition?

Tmrw I will swap the slave solenoids from the good engine to the bad engine and see if that helps.

As for running a ground from the battery to the starter; I can't get to it without removing the manifold and risers from both engines so leaving that until last resort. I can feel the solenoid on top of the starter but can't tell what I'm feeling.

Thx for all the help so far.

Brian

 

[Don S]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

 

[Fun Times]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

X 2 Don, i'm kind of lost myself.

I know the Purple wire is supposed to get power from the key switch B side and go through pin 5 of the boat/engine harness to wake up the ECM. I don't have time to look right now but Don you may recall the tahoe boats have a separate fuse somewhere around the engine harness buried & if blown, the engine did nothing. The guy posted a photo of it, Maybe he has something like that. I recall the formula boats doing something different with wiring vs normal boat, lol. Thats all just a guess at this point.

dolemite_1, Have you checked all the fuses on the engine itself by the ecm? Also try following the wiring harnesses between the helm and engine looking for relay type boxes, modules, etc.

 

[Don S]

Re: 350 Mag -Wont't start - No buzzer or guages working but has power to keyswitch

X 2 Don, i'm kind of lost myself.

I know the Purple wire is supposed to get power from the key switch B side and go through pin 5 of the boat/engine harness to wake up the ECM. I don't have time to look right now but Don you may recall the tahoe boats have a separate fuse somewhere around the engine harness buried & if blown, the engine did nothing. The guy posted a photo of it, Maybe he has something like that. I recall the formula boats doing something different with wiring vs normal boat, lol. Thats all just a guess at this point..

Didn't even think about that fuse. Thanks for coming up with that possibility. I thought that was only on the newer models (08 and above) I still have info on the 06 and that fuse isn't mentioned, but since this is a replacement engine, who knows.
Here is the thread. Start with post 65 and look at the pictures of that hidden fuse. http://forums.iboats.com/mercruiser...den-fuse-4-3-tahoe-q4-please-help-554420.html