boat wont start

[ussoldier_1984]

mercruiser 4.3 wont start its a 1995 model. got closer to the answer today.... I was told if I run a wire from the postive terminal of the battery to the coil see if it starts. it sure does but when the jumper is not there it doesnt start what would be the cause of this..... somthing is steeling power when im cranking. or maybe the shift interupter switch is bad? I have no clue please please help

[ss3964spd]

Possibly the starter. Specifically, the starter solenoid.

You'll need the wiring diagram to confirm because I'm not positive if the ignition circuit goes through the starter solenoid on a 1995 engine.

[ed & inge]

when you turn on the key....do you hear the alarm for just a few seconds..........if not... problems with wires.......is the starter engine working take a take an AC/DC tester, and try to find the leak........

tell us what's working and what's not than we can think with you

greatz, ed

[ussoldier_1984]

well I think my coil bit the dust it seems I have a week red spark coming from the coil. Yes the alarm sounds when i turn the key on the ignition/electric fuel pump go through the starter but I didnt like that so I eliminated it from the starter when I replaced my starter with a standard chevy starter so now it gets the power from the ignition switch to the oil pressure switch to the coil then it goes to the fuel pump. but If it is the coil bad I think I still have an issue with a bad wire. I know from the ignition switch to the 10 pin connector is good its after the 10 pin connector where im leaking power. Like I said when i jump the ignition coil to the batter it started up. but now my coil I think is bad. It will not start at all now. they say a mans happiest 2 moments in his life are 2nd best is when he gets his boat 1st best is when he sells it. I really am starting to understand that saying now haha

[ussoldier_1984]

ok update it turns out it was just a bad oil pressure switch went bad. I jumped it and everything works great except my timing i turned the dist a little prior to see if bumping the timing would help. now i have it back approx running smooth but I cant figure out where the 8 deg btdc is because i only have a v mark above the crank pully no deg marks soooo how do i get it timed properly or should I time it how it runs out on the water?

[ussoldier_1984]

Think i found out the answer to my question myself. I read online that the thunderbolt IV ignition has a mbt (mean best timing circuit) and that purple wire i was asking what it was is called wire 13 which needs to be grounded out to disable the mean best timing circuit to get a baseline timing of 8 deg btdc. does this sound correct to you guys?

[Watered down]

Originally Posted by ussoldier_1984

when I replaced my starter with a standard chevy starter

I hope it is a marine grade starter, or you will be replacing you boat!

[ussoldier_1984]

nope not a marine starter been working great all season and its not gonna blow the boat up, you have a better chance of blowing your boat up with all mercruiser parts and not turning on the blower then using a chevy starter

[seapuppy]

the coast guard doesn't authorize the use of a standard chevie starter due to it not being explosively protected....doesn't matter that a standard car starter will do the job....if by some strange reason you do get an explosive event on your boat...insurance won't pay up.....plus the fact that you maybe endangering others lives.....
just my suggestion..but I'd replace it with a marine unit before next season.....


SP

[TonyA]

grounding that wire is only one part of setting the timming at 8dge you need to bring the idel up to I think 1300 rpm then set youy timming at the 8 dge ( timming marks are on the harmanic balancer.) after seting the timming shut the engine down,remove the shorting out wire, restart the engine and bring the rpm back to its 650 rpm. or what ever your setting are