No start 2.5 efi 200

[Whaaaaat]

Gonna start this thread since I won't get a chance to diagnose the boat for a week at least. Something for us to ruminate on outside the politics section.

Background. For about a year I've been chasing a Intermittent no start condition. I could never replicate in the shop until recently. I found that my engine side harness had gone bad and voltage was bleeding across the pins. This was acting as a kill switch. I replaced the engine and the boat harnesses. Used the boat a few times with no trouble. Think it's fixed.

Sunday I put it in for a afternoon cruise. Run a little bit probably less than an hour, I notice the tach is acting funny, bouncing some and seemed to be off by my ear. I can't be sure it was off as I was testing a different prop.

Stop at the sandbar for maybe an hour or so. Then try to start, just spins. Spinning plenty strong. No coughing no sputtering, just spinning. Pull the cowl, fuel pump runs like it should when key is cycled. I didn't notice a sheen but my buddy that was with me said he could smell fuel while cranking. I very timidly grabbed a plug wire with wet hands standing in saltwater knee deep. I wasn't zapped.

Went under dash and disconnected kill wire. Still nothing just cranking. Wiggled all the grounds, everything nice and tight. While cranking my tach is reading 3k, I know something's not right. At this point I'm thinking stator is hot and failing. I grabbed a water bottle and sprayed the stator from under the flywheel to see if I could cool it. [Should have gotten water from cooler]. Anyway nothing. I give up and get a tow. Takes a couple hours until it's back in my yard.

I put the hose to it just to see if I could get some fresh water thru it to rinse. Turn the key. She coughs once fires up perfect second try.

I'm still leaning toward stator as my first thing to check when I have room in the garage. Will use a heat gun to try and replicate symptoms. Other than that I'll have to open the manual.

Also trigger is new in the last year.

200 efi with switchbox ignition no idle stabilizer boxes.

[mach351]

How old is the harness/keyswitch? Try unplugging the cannon plug next time it won’t start and jump it at the solenoid to see if it runs?

40amp or 16?

[Whaaaaat]

Boat Harness, key switch, and engine harness all new. Writing to ecm and related efi still original but look good.

Didn't think efi would run with cannon plug disconnected. But I've never tried.

40 amp. Black flywheel. No stabilizer boxes.

[JR IN JAX]

The bouncing tach sounds like a rectifier/harness problem.

[Whaaaaat]

I'm with you on that. I lost tach signal out of one rectifier a couple years ago and put the grey wire to the other. Been fine ever since. 2 bad rectifiers wouldn't cause no start, not that I'm aware of. I suppose they could hurt the stator
Charge windings.
The bouncing was fairy minimal but definitely there. Glitchy might be a better description. It's the tach reading 3k at cranking speed when it wouldn't start that points me at the stator.

[Whaaaaat]

If it is stator. I really don't need the 40 amps. Only draws I have are the gps and trim. Can't hear the radio while running and plenty boats at the sandbar with monster stereo systems.

Anybody got a cherry lightweight flywheel there tired of looking at?

[David - WI]

2 bad rectifiers wouldn't cause no start, not that I'm aware of.

Depends if the diode fails "open" or "shorted"... you're supposed to check voltage while cranking, I think. https://www.cdielectronics.com/wp-co...th-Edition.pdf

On p68 or 70 maybe?

[mach351]

If it is stator. I really don't need the 40 amps. Only draws I have are the gps and trim. Can't hear the radio while running and plenty boats at the sandbar with monster stereo systems.

Anybody got a cherry lightweight flywheel there tired of looking at?

go see Ed

[Whaaaaat]

Yes stock laser injection. I would think 16 amp would keep up. That's how 260 are correct? I could always keep one of those lightweight roll up solar panels on board for when it's resting at the sandbar.

[mach351]

A good charged battery will last all day on a 16amp laser motor as long as you are smart with it.

[David - WI]

Anybody know what rpm they actually hit the rated amps at... 16 or 40-amp; they don't make that at idle?

[Whaaaaat]

Had a chance to look at it today. Tearing my hair out.

Started fine in the morning and ran on the hose for 30 minutes. Shut it down took a break found an umbrella( felt like a 100 today no wind)

Tested after about 15 minutes. No start.

I think great its finally broken where i have tools. I put spark gap tester on it. Spark on #3 intermittent on #2 even less intermittent on #1. I'm lost now this makes no sense. Out comes the DVA and meters.
Voltage and ohms test good on stator.

Ohms test good on trigger. cdi has a spec to test 2 wires for voltage from trigger. Spec is 4volts. I have 1.5volts. Each lead from trigger to ground is .5 volts. Mercury specs 1-4 at cranking. Can a trigger be weak and not dead?

Swapped 1 switch box for used spare with no change.

Swapped flywheel with used spare no change.

Boxes ohm 14.1k on bias to case.

Test for voltage at kill post on boxes was way low. Mercury wants 200volt. I have 4volts.

I either have a bad 10 hour old trigger or 3 bad switch boxes.

I'm going to double check some things tomorrow before it gets 100 degrees outside.

[Smalltownbassin]

Ohms test good on trigger. cdi has a spec to test 2 wires for voltage from trigger. Spec is 4volts. I have 1.5volts. Each lead from trigger to ground is .5 volts. Mercury specs 1-4 at cranking. Can a trigger be weak and not dead?

*copied from archives*

all tests need to be done with a DVA
the DVA will let you read AC volts on a dc scale without the voltage jumping all over the place
The trigger voltage with a DVA should read 4 v at cranking speed
across the 2 corrosponding wires
( the same wires you would do the resistance test on)
When testing the trigger ...grounding the meter lead will not help you at all because the trigger is not grounded to anything its emitting AC volts!

the trigger trips a SCR in the switch box when the AC volts are +
the trigger is connected to cyls 1+4...2+5....3+6
when + voltage is applied to #1 post on the switch box #1 coil will fire
#4 switch box post gets negative voltage which does not trip the SCR but gets re directed to the charge capacitor and gets stored as negative voltage to be stored until the coil fires

when the voltage flips + voltage goes to #4 and trips that SCR and fires that coil #1 post gets negative voltage and redirects the negative voltage to the charge capaciter.

All the switch box inputs are ACvolts
the out puts are DC volts

Test Bias circuit
DVA red wire to ground
DVA black wire to WHT/BLK
1-6v@cranking speed


Test stop circuit
DVA red to BLK/YEL
DVA black to ground
200-400 v @ cranking speed

test High speed stator
DVA red to red/wht stator wire
DVA blk to ground
25-50 v@ cranking speed

Test Stator low speed
DVA red to blu/wht stator wire
DVA blk to ground
100-265 v @ cranking speed

test for coil
DVA red to coil+
DVA blk to coil-
90-145 @ cranking speed

if the trigger test is ok and the bias test fails its the switchboxes
if the trigger test is good and the stop circuit test fails its the switch boxes

Maybe this will help.

[XstreamVking]

I have had intermittent triggers before. Run fine, shut down and re-start after a while would lose fire on 3 cyls.

[Whaaaaat]

Everything passes mercury test procedures. Next step replace switch boxes and test again.

Trigger passes mercury test. Low voltage according to cdi test procedures.

Going to replace all 3

Will blue racing boxes work on 40amp system, and are they worth the extra$ ? Difference not that much.