1989 Mariner 25 Won't Start

Last year, my motor would run fine at mid to high speed. It was hard to start and stalled at low speed. I replaced the spark plugs. I replaced the stator because it has a low speed output and I hoped that would solve the problem.

While I was at it, I replaced the trigger. No change, still hard to start and would not idle. I properly winterized the motor, including burning up the gas in the carb.

This spring, I can't even get it to sputter. I cleaned the carb again. When I pulled a spark plug and held it against the block to see if there was a spark, I got zapped while I was holding onto the boot. I replaced both wires with automotive wires because they were available. I got zapped again. Using a spark tester, there is a spark. There are no external sparks when cranking the motor in the dark. The only thing that ever happens is that it will have one backfire POP every now and then. Spraying starting fluid (ether) into the carb does nothing.

The resistances for the coils are good. One cylinder is at 130 psi and the other is at 135 psi. The motor turns over with plenty of speed.

I just ordered a DVA adapter.

I'm lost. Please help.
TIA,
Ed_M

Re: 1989 Mariner 25 Won't Start

Sounds like what just happened to my Merc 25. While I was running though. You see my threads on here under "Need help fast!". What I ended up doing was fixing any little hint of a leak on the fuel system and it did'nt help. I adjusted the carb and it runs great now. My problem was it was running too lean (would run with the enricher / choke). I put the motor in water (river on the trailer), started it and put it in forward. While it was running I turned the idle screw counterclockwise a fraction of a inch at a time until it evened out. Turned it til it began to die and turned it clockwise about a 8th of a turn. Thats all I needed to do. Worth a try...took me all of about 20 minutes.

The carb only uses that idle screw at idle. When it hits about 1,200 RPM's it runs off the high speed jet on the bottom of the carb and the idle jet pretty much does nothing until you return to idle.

Re: 1989 Mariner 25 Won't Start

Choking doesn't make any difference, but I'll give the idle screw a try. When I put the carb back together I set it at 1.5 turns. What should the setting be?
Thanks,
Ed_M

Re: 1989 Mariner 25 Won't Start

1 1/4 from lightly seated when you start. Than 1/4 turn either direction from that point. Clockwise is lean and counterclockwise is rich. Set it, start it, put it in gear (in water) and turn it clockwise til it begins to die, then counterclockwise til it begins to die, then about 1/8 turn clockwise. Want it on the rich side. If you set it at 1 1/2 at start then it's probably WAY lean and most likely won't start.

Re: 1989 Mariner 25 Won't Start

Weather permitting, I'll try it tonight as you stated and keep you posted. If turning counterclockwise makes it richer then 1 1/2 turns would be too rich.
Thanks,
Ed _M

Re: 1989 Mariner 25 Won't Start

I adjusted the idle screw and nothing happened.

My DVA adapter arrived yesterday so I checked the ignition system. This is what I found:

Stator:
Low speed; Black/Yellow to ground: 3160 ohms (spec 3250-3650), 6 volts (spec 180V+). The resistance is a little below spec. The 6V is way below spec.
High speed; Black/White to ground: 7.2 Megaohm = 7,200,000 ohms (spec 200-250), 31 volts (spec 25V+). The resistance is way above spec.
This was just replaced last fall. I threw the old one out. The spark plugs are sparking. I get a shock when I hold onto the spark plug boot. Is this defective? Could something else be causing this? Could I be doing something wrong?

I just looked at the ignition: http://www.boats.net/parts/search/M...2PD/Ignition-Electrical Components/parts.html
I replaced the 86617A13 Stator assembly. What is the 86704A2 Stator Assembly, Auxiliary? How can this be checked? What are the chances that this is the problem?

Trigger:
Brown/Yellow to Brown/White: 730 ohms (spec 750-1400), 9.2 volts (spec 4V+). The resistance is a little low.
Brown/Yellow to ground: Open resistance (spec is open), 3.7 volts (spec 1V+)
Brown/White to ground: Open resistance (spec is open), 3.1 volts (spec 1V+)
This was also replaced last year. How much does the low resistance concern you?

Left coil: + terminal to - terminal: 3.0 volts (spec 150V+)
Right coil: + terminal to - terminal: 3.5 volts (spec 150V+)
Both voltages are way too low. The spark plugs are sparking. I get a shock when I hold onto the spark plug boot. Are these defective? Could something else be causing this? Could I be doing something wrong?

Both coils, + terminal to + terminal: 155 volts

I have the 745A15 Switch Box. Does this mean that I have the 332-7452 Switch Box that is commonly referred to? If not, then are the specs the same? If not, then what are the specs?

How can I check the Switch Box?

TIA,
Ed_M