check or replace your igntion switches. Check every connection from your battries, to the alternators to starters. sometimes they loosen and will throw it off.

Loose kill switch?

[QUOTE=zx14k;3409867]i have about the same problem with 2 different boat.first one was a bad connection behind the dash for the ignition switch as soon as i give some thhrottle engine die cause of more vibrations.second one, moisture in the fuse box,voltage was fine at the ignition switch at 650 rpm but lose it at 1200 rpm.all new fuses and contact cleaner at the fuse box and all is fine.

note in both case it appen to me early in the spring.[/QUOTE

i think you did not read my post but anyway try this it is the way i find my problems:take a long wire direcly from the battery to the ignition switch and bypas the kill switch this way you will see if you have something bad in the dash or in the fuse box.

[QUOTE=zx14k;3412808]Ok, thanks, yes I read your post, and I'm going in that direction now. Thanks for your tips, will try that.

ok, I have checked the fuel, it was OK. I have checked all the wiring and found two things. One thing was poor connection at one of the batteries (+). The other was the port ignition switch, but it worked, just the spring broken, i.e. have to manually turn back the key one step after engine started.

Anyway, i can't understand how these defects can make BOTH engines behave like this at the same time!?!

As I described earlier, both engines starts and runs excellent in neutral, all the time. Then when engaging drive on one of the engines, that engine dies. The other still running steady in neutral. Then trying to engage the other drive, it also dies. And stop instantly. The props just makes 1/8 turn. I have tried everything, for example engaging both drives at the same time, also with increased idle, also with only one engine running. Also tried reverse, but no difference.

AND suddenly it works again. I mean BOTH engines works again.

So, what except the fuel tank is common for both engines? Is there a vibration switch, or any other electrical system? Checked the kill switches, they are OK.

dont know if its possible but maybe when you switch into gear it throws the throttle cables off because they are loose. I would put muffs on it and start here up and have somebody switch it into gear and watch the throttle cables and everything and see if anything is happening. That ignition switch could be the culprit, I would change it. Before you start replacing parts I would try these things. Put some fuel treatment in it, if its a carbed engine spray out the carbs with cleaner, because maybe they are dirty. Take your batteries out and have them checked at autzone, maybe once you put a load on them they die out. If none of that works im out of ideas.

I had a similar issue and it ended up being the carb was to lean at idle, I backed my screws out a 1/4 turn to richenn it up a little and it was fine after that

Ok, but my problem comes and goes. And at exactly the same time for both engines. Engines runs perfect, very good low-end torque. So it hasn't anything with engine setting to do. The problem seemes "digital". When applying drives engines just dies. Instantly. Then putting shift in neutral and engines starts immediately which means engine has perfect mixture when killed, i.e. seemes like something makes the ignition fail...

Please test the shift interrupt switches that MustangMark commented on above. The interrupts could be corroded/failing causing a problem now and then.

What these switches do is turn off the engine for just a moment in time when the shifter is pushed into gear. These are nothing more than tiny micro limit switches that do have a life, and once the number of cycles is hit and/or corrosion gets to the internal contacts it is done. Could be your moment in time is quite lengthy. For a test, just bypass the interrupt on one engine to see if the problem is solved, be very careful the idle speed on that engine is as low as it will go to avoid hurting the drive when doing the test. Or if you would trust a voltmeter, connect it across the contacts and see if the voltage is interrupted only shortly when shifting from neutral to drive with the key in the on position but the engine not running. This test with the voltmeter would work best with one the old school simpson analog meter where you can watch the needle move, as the interrupt may be too quick for a digital display to catch clearly.

Ok, but since I have Bravo's, there are no shift interruptor switches, right? I do have some micro-switches, but I think they just prevents from starting the engines with drives forward (or reverse).