Engine problem - '85 Mercruiser 170

[spareparts]

try a remote tank just to eliminate fuel supply as an issue. Take a volt meter with you, when it shuts down, check voltage at the + terminal on teh coil, it should be above 8 volts, if it won't start back up, run a jumper wire from the + terminal on teh coil to the + termoinal on teh bagttery, if it runs then, you're resistor wire(purple/white stripe) is breaking down. Cut the harness back till you can find a purple wire, splice a new purple wire intoit and repalce the purple/white with the new wire to the coil. Also, make sure the wires to the pertronix didn't get chafed when you installed it, make sure the black wires runs to the - terminal on the coil is good and secure. Is that a new coil? Two more things, disconect the tach wire at the coil(grey)and see if it runs better. If that doesn't help, disconect teh shift assist wire at the shift switch(white/green stripe). Becarefull if you disconect the shift switch, it will be difficult to get it to come out of gear. You may have to cut teh switch off to get it to shift. Stay out in open water doing this test(away from docks and other boats)

If that doens't get the job done or if youhave any questions, call me next time your on the boat, I'll walk you thru a few things. David Hall (843) 532-9148

[scook]

Thanks David - I'll try all that stuff before bothering you. I really appreciate your generosity - you saved my sanity a few years ago when I was fixing the water pump and it looks like you may do it again.

Thanks again - Scott

[bradford]

Originally Posted by spareparts

If that doens't get the job done or if youhave any questions, call me next time your on the boat, I'll walk you thru a few things. David Hall (843) 532-9148

That's gold right there.

[THEFERMANATOR]

Doesn't the PERTRONIX need a full 12 volts to work? I thought when you went to a PERTRONIX, it is reccomended to go to a matching coil and do away with the resistor.

[twhrider2]

Ferm is spot on... that's the way mine is set up

[spareparts]

been a while since Ive done one, but they used to require a minimum of 7 volts. I always bypassed the resistor regardless just to eliminate it causing issues. I haven't done one recently, but 12 volts is better than < 12 any day

[scook]

I got their flame thrower coil with it and cut out the resister wire. I've got 12 V plus. I read Spare's suggestion that I should check it right when it pooped out to be sure something wasn't changing as a result of operating the engine - temperature or some other cause. Intuitively, I don't see what would cause the voltage to drop and if it did, would it cause RPMs to decrease as opposed to just dropping off suddenly,to zero. Of course, my intuition hasn't got the problem fixed either.