Running at 75%, engine dies and wont restart (VRO pulse line leak?)

[guitman32]

Motor: 88-91 Evinrude 175 with VRO2 (w/oil delete; running premix)

Issue: Ran at about 75% for roughly 25 mins absolutely no issues. Anchored at a reef for about 45mins, restarted and continued to the inlet.

All of a sudden, running at about 75%, she just dies. Sounded like I either ran out of gas or spark. Cranked fine, and would fire up intermittently with the choke open and throttle advanced in neutral to various points (sometimes close to wide open, sometimes only about 25% advanced) - but only after primer bulb is pumped hard. No amount of pumping keeps the engine running any longer.

Either way, when she does fire she would run then slowly sputter and die after a few seconds. The starter cranks fine and when it does fire up (with the ball primed hard), it sounds like its running on all cylinders so it seems spark is ok as well.

Changed battery and ran on an external tank with no improvement. Still the same issue so I assume its on the motor side. Fuel filter looks clear.

Noticed the pulse hose going into the block is a little worn and when I wiggle the hose the whole things moves up to the top of the nipple.

Could a vacuum leak from the block to the VRO pump (pulse line) cause a terminal fuel restriction and the symptoms I describe?

Other factors to consider (may or may not be related): There is a fuel starvation issue that was causing a temp alarm at WOT and just under WOT, but this goes away when I run on an external tank.

Also, charging system is weak and battery drains after 3ish outings. Suspect the rectifier/regulator and/or stator. My tach is pegged always, battery connected or not.

 

[ezeke]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

The pulse line has to be airtight or (1), air will enter the engine causing it to run lean, and (2). The fuel pump cannot operate correctly.

You have a vacuum switch that sounds a constant alarm just like the overheat alarm when there is a fuel obstruction. You should test your fuel system, especially the anti-siphon valve and any fuel filter(s).

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

The pulse line has to be airtight or (1), air will enter the engine causing it to run lean, and (2). The fuel pump cannot operate correctly.

You have a vacuum switch that sounds a constant alarm just like the overheat alarm when there is a fuel obstruction. You should test your fuel system, especially the anti-siphon valve and any fuel filter(s).

I have a single alarm with two connecting wires (one to the ignition, the other to the engine - obviously aftermarket), which gives me either an intermittent beep at slow intervals or a constant alarm. Problem is I do not know if the wire going to the block goes to the temp or the vacuum switch. I will check today, along with the vacuum lines.

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

Also, in pondering the vacuum switch operation in the event of a vacuum leak on the VRO pulse line - since it is connected between the fuel filter and the pump, if the pump wasn't sucking fuel, the switch won't notice a vacuum...is my logic sound?

 

[jonesg]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

Sounds like you have a few problems, if running on a temporary tank stops the alarm then theres an obvious plumbing problem to fix first.
You would do well to get the shop manual so you'd know what each alarm sounds like and how to test them.
www.outboardbooks.com

Put a meter across the battery termials and see whats its putting out, with all the other problems it might be corroded battery cables or loose terminals.

 

[ezeke]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

Also, in pondering the vacuum switch operation in the event of a vacuum leak on the VRO pulse line - since it is connected between the fuel filter and the pump, if the pump wasn't sucking fuel, the switch won't notice a vacuum...is my logic sound?

The vacuum switch is only on the incoming gasoline line. It senses a blockage, not a leak, and sounds a constant alarm.

When the fuel obstruction alarm sounds, it's to let you know that the fuel pump is not capable of overcoming the obstruction so that you can correct the problem.

 

[d.boat]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

This is just a hit and run comment/suggestion because I once had similar, frustrating symptoms. I had sheared my flywheel key and of course that messed up the ignition/timing thing.

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

Sounds like you have a few problems, if running on a temporary tank stops the alarm then theres an obvious plumbing problem to fix first.
You would do well to get the shop manual so you'd know what each alarm sounds like and how to test them.
www.outboardbooks.com

Put a meter across the battery termials and see whats its putting out, with all the other problems it might be corroded battery cables or loose terminals.

Thanks, have a shop manual. Reason I had no idea about the alarm is that the wiring is completely modified from the manual; eg VRO delete, the buzzer is aftermarket and only has one lead as described earlier, etc

I tested today and confirmed it is connected to the vacuum switch. There are no wires connected to the temp sensors.

I would love to test the plumbing, but cant as the motor wont start. Thus I need to get it running before I can diagnose the fuel starvation at high RPMs issue.

The pulse line has to be airtight or (1), air will enter the engine causing it to run lean, and (2). The fuel pump cannot operate correctly.

You have a vacuum switch that sounds a constant alarm just like the overheat alarm when there is a fuel obstruction. You should test your fuel system, especially the anti-siphon valve and any fuel filter(s).

The vacuum switch is only on the incoming gasoline line. It senses a blockage, not a leak, and sounds a constant alarm.

When the fuel obstruction alarm sounds, it's to let you know that the fuel pump is not capable of overcoming the obstruction so that you can correct the problem.

I confirmed the alarm is connected to the vacuum switch, but never sounded or gave any warning before she cut. I replaced the worn looking pulse hose to no avail. After some cranking, I found that if I would fiddle with the throttle in neutral, at certain settings it would fire and sound somewhat erratic, then die. Basically the same thing it was doing when I would try to restart her in the water.

So, I reverted to the standard diagnosis procedure:

1) Compression is good
2) NO SPARK ON ANY CYLINDERS as measured at the plugs.

So, alas it was not a fuel issue, I simply lost all spark.

Was only able to test the rectifier, tested the yellow to yellow leads, reversed them, got the same reading both ways. Does this mean my rectifier is shot? Can a blown rectifier cause me to lose all spark?

I have the diagnosis procedure to test the ignition, but I am wondering if anything jumps out as the culprit (running and then suddenly losing all spark)?

 

[emdsapmgr]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

The ignition on that engine is separate from battery charging. You may have a charging issue, based upon your tach readings, but it is hard to work on that issue if the engine won't run. Unlikely all 6 coils went out all at once. That leaves you with 3 expensive items, the stator, timer base and the power pack. If you have a peak-reading voltmeter, it is worth your time to compare the voltage readings on those components with the specs in your factory manual's ignition troubleshooting section.

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

The ignition on that engine is separate from battery charging. You may have a charging issue, based upon your tach readings, but it is hard to work on that issue if the engine won't run. Unlikely all 6 coils went out all at once. That leaves you with 3 expensive items, the stator, timer base and the power pack. If you have a peak-reading voltmeter, it is worth your time to compare the voltage readings on those components with the specs in your factory manual's ignition troubleshooting section.

Hey, thanks for chiming in on my new issue...really appreciated the tip on the loose magnets. Looks like there may have been more damage than originally anticipated.

Will do re: the test procedure. As you may have noticed, there was some confusion on the model number from my previous thread (with the magnet issue)...I now confirmed its an 89. This was causing me great confusion with the test procedures in the manual. Now I have the correct test procedures printed and going to try and catch some daylight and run the tests tonight. Ill let you know how it goes.

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

Test procedures performed so far (before getting rained out - 2 days running):

1) Killswitch has been deleted so no need to perform the killswitch delete procedure

2) Rectifier test:

-Tested using multimeter on resistance: ground to yellows then reversed leads from yellows to ground:
Have readings going both ways - does this indicate blown diodes?

-Now tested red to yellows and reversed leads from yellows to red: Have reading going one way, the other the multimeter flickers from OL to a reading:
Doesn't settle on a resistance - is this normal?


3) Sensor coil resistance (readings taken from 4-wire plugs coming from the timer base):

-Starboard D-to-Port D wires: Resistance in spec
-Port and Starboard side D-to A,B and C connectors: Resistance NOT in spec
-Ground check on all wires: Passed (no grounds)

Does this mean the timer base is blown?? (note that I still need to perform the sensor coil output test)

4) Charge coil resistance test:

-Resistance between A-to-B and C-to-D: Resistance in spec
-Ground check on all wires: Passed (no grounds)

Charge coil resistance check OK


Tests outstanding:
Charge coil output
Sensor coil output
Power pack output

Questions:
Does it look like I can safely say I need a regulator/rectifier and a timer base?
Will an out-of-spec timer base cause all cylinders to loose spark?

 

[emdsapmgr]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

I prefer to condemn the timer base,power pack and stator based on their voltage outputs when cranking, rather than the resistance checks shown in the factory manual. Yes, a bad timer base will kill your ignition.

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

I prefer to condemn the timer base,power pack and stator based on their voltage outputs when cranking, rather than the resistance checks shown in the factory manual. Yes, a bad timer base will kill your ignition.

Performed the following tests today:

1) Charge coil output test:

-Cranking grounding test:
Get readings on all leads when cranking, per manual this means there is a short to ground somewhere

-Cranking output test:
Get readings of 140VAC for both tests, recommended spec is 200 or above.

2) Sensor coil output test:

-Cranking sensor coil grounding test:
Get readings on all leads when cranking, per manual this means there is a short to ground somewhere

-Output test 1:
Get readings of .15-.16VAC average for each test, though get a spike on initial crank, then reading settles on .15-.16. Recommended spec is 0.2VAC or higher

-Output test 2:
Get readings of ~0.4VAC for each lead, though several read in the .35VAC range, and one reads .55VAC. Recommended ranges are 1.2VAC or higher.

3) Ignition coil resistance test: Passed both tests on all coils

I wanted to perform the power pack output test, but have no idea what a "Stevens load adapter" is, so Ill do my research and perform the test when I get the chance.


So, does anyone want to take a stab at whats going on?

Per the manual, both my stator and timer base are out of spec. This plus my rectifier diodes look like they are blown. Do the readings above indicate any particular cascade of failure? I find it hard to believe that one minute shes running fine and the next both components are fried. Is it possible one faulty component is throwing off the other readings (eg fried stator throwing off the time base readings??). Do the grounding tests point to a particular point of failure (eg stator coil wire insulation melted causing a short??)

 

[emdsapmgr]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

Yes, both your stator and sensor coil outputs are low, esp the stator. Prior to replacing both of them make sure you are getting the proper rotation on the starter for your measuremets. The tach should indicate the starter is rotating the crank at least 250 rpm while you are taking measurements. If you have a weak battery, any slow spinning of the crank could affect your test results. If the starter cranking rpm checks out, looks like you have two components that are out of factory spec.

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

Yes, both your stator and sensor coil outputs are low, esp the stator. Prior to replacing both of them make sure you are getting the proper rotation on the starter for your measuremets. The tach should indicate the starter is rotating the crank at least 250 rpm while you are taking measurements. If you have a weak battery, any slow spinning of the crank could affect your test results. If the starter cranking rpm checks out, looks like you have two components that are out of factory spec.

Unfortunately I don't have a working tach so I can't verify cranking RPMs. Is it reasonable to assume that even if she was cranking at less than 250-300 RPMs, I should at least be getting a weak spark on some cylinders, versus NO spark on ANY cylinders?

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

Bit the bullet and ordered new timer base, stator and rectifier. At the very least I am going to change the battery-engine connections and check all harnesses and wiring for issues before installing the new parts.

I tested the ignition coil resistance, all passed, but I read that they can be an issue even if the resistance is in spec. Now I am just banking on the power pack being ok.

Do I run a risk of damaging the new components if I run it a defective power pack?

Basically I'm considering new coils and possibly a power pack as preventative maintenance, and having the old ones as spares...

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

UPDATE: Have a new stator, timer base and rectifier waiting to be put on. In the meantime I re-ran new 4ga battery cables, cleaned all terminals, etc. and am in the process of verifying the instrument wiring.

I observed two issues which I need some advice on:

1) It seems that the grey tach sense wire is not connected to the tach at all (no continuity on any of the tach wires - though the grey wire does get continuity on the ignition 12v). This doesn't make any sense, and maybe I am missing something, but it concerns me that the wiring from the rectifier to the console could be suspect.

2)I am getting voltages (~7.5VDC) on both black/yellow killswitch wires coming from the ign switch. I read that this is a sure fire way to kill the power pack. Is this a cause for concern? Is the ignition switch suspect?

Its gonna be a real PIA to trace back all the wiring under the console, but if it what I have to do, then so be it...advice welcome.

 

[ezeke]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

The gray wire should lead through the main harness to the terminal block on the engine. It should have no connections at the helm except to the tachometer. Any external voltage applied to the gray wire will instantly destroy your rectifier.

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

The gray wire should lead through the main harness to the terminal block on the engine. It should have no connections at the helm except to the tachometer. Any external voltage applied to the gray wire will instantly destroy your rectifier.

Confirmed all instrument-harness-engine wiring, mapped all connections. Gray lead was corroded at tach causing no signal. I dont think any voltage was seeing this wire. The rest of the wiring looks ok minus corrosion and the like, purple was not used at just sitting under the console.

I am installing a new ign switch today, since I pulled the old one and though it looks ok visually the connections are intermittent for the choke and run positions. Not sure whats going on, but its a cheap part and worth the savings in headache.


Now my only concern is the voltage at the killswitch wires (A+D) at the power pack. Could this have possibly fried the pack?

 

[guitman32]

Re: Running at 75%, engine dies and wont restart (VRO pulse line leak?)

So in the spirit of education, developments are as follows:

In the process of waiting for my new parts I decided to address the wiring in the boat. Ended up diagnosing a faulty ignition switch which might have been causing rogue voltage on my killswitch leads.

Also built a DVA adapter and purchased a Stevens Load adapter and re-ran all tests (what the hell right)...

Stator: checks out OK
Timer Base: checks out OK
Power pack: low voltage output on primary wires of all cylinders (varies from 90-145 on one)
Retested spark: No spark on starboard cyl bank. Either extremely weak or no spark on port (saw weak spark on cylinder with highest reading from power pack- 145v)

Moral of the story: dont skip the DVA meter bit...

Putting the new power pack on tomorrow.